Revista y Edición

Volumen 71 (2022): Edición 1 (January 2022)

Volumen 70 (2021): Edición 1 (January 2021)

Volumen 69 (2020): Edición 1 (January 2020)

Volumen 68 (2019): Edición 1 (January 2019)

Volumen 67 (2018): Edición 1 (February 2018)

Volumen 66 (2017): Edición 1 (December 2017)

Volumen 65 (2016): Edición 2 (December 2016)

Volumen 65 (2016): Edición 1 (December 2016)

Volumen 64 (2015): Edición 1-6 (December 2015)

Volumen 63 (2014): Edición 1-6 (December 2014)

Volumen 62 (2013): Edición 1-6 (December 2013)

Volumen 61 (2012): Edición 1-6 (December 2012)

Volumen 60 (2011): Edición 1-6 (December 2011)

Volumen 59 (2010): Edición 1-6 (December 2010)

Volumen 58 (2009): Edición 1-6 (December 2009)

Volumen 57 (2008): Edición 1-6 (December 2008)

Volumen 56 (2007): Edición 1-6 (December 2007)

Volumen 55 (2006): Edición 1-6 (December 2006)

Volumen 54 (2005): Edición 1-6 (December 2005)

Volumen 53 (2004): Edición 1-6 (December 2004)

Detalles de la revista
Formato
Revista
eISSN
2509-8934
Publicado por primera vez
22 Feb 2016
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

Volumen 62 (2013): Edición 1-6 (December 2013)

Detalles de la revista
Formato
Revista
eISSN
2509-8934
Publicado por primera vez
22 Feb 2016
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

35 Artículos
Acceso abierto

Genetic characteristics reflecting the population size and disturbance regime of Siebold’s beech (Fagus crenata Blume) populations at the northernmost distribution

Publicado en línea: 01 Jul 2017
Páginas: 1 - 6

Resumen

Abstract

To understand the population dynamics of tree populations at the range limit of a species’ range, it is important to determine which population size and disturbance regime are critical to genetic diversity. Siebold's beech (Fagus crenata Blume) is a major canopy tree species of cool-temperate forests in Japan, with the northernmost distribution reaching the Kuromatsunai Depression in southwestern Hokkaido, Japan. We examined the genetic variation and dynamics of three beech forests, with different disturbance history and population attributions in the northernmost population. The Tsubamenosawa (TSU) and Sannosuke (SAN), both natural forest, have historically experienced little artificial disturbance, whereas the Soibetsu (SOI), a secondary forest, was intensively logged, and thus strongly disturbed in the past. In total, 35 alleles were detected among 12 loci, encoding 9 enzyme systems. At TSU, He and RS were 0.141 and 2.280, respectively. At SAN, He and RS were 0.142 and 2.604, respectively. At SOI were 0.182 and 2.628, respectively. Parameters of genetic diversity changed with population size, small isolated population indicated low values. Gene flow distance for low density mature trees in the natural forests was greater than that for high-density secondary forest. However, effective population sizes (Ne) were 34.7, 64.3 and 60.3 in TSU, SAN and SOI, respectively, reflecting differences in the density of mature individuals. The results suggested that the population with the low density of mature trees kept genetic diversity through long distance gene flow. The mature tree density affected the effective population size in the northernmost beech populations.

Palabras clave

  • allozyme
  • population size
  • disturbance regime
  • Fagus crenata
  • range limit
Acceso abierto

Age Trends in Genetic Parameters for Growth and Resin-Yielding Capacity in Masson Pine

Publicado en línea: 01 Jul 2017
Páginas: 7 - 17

Resumen

Abstract

Masson pine (Pinus massoniana Lamb) has long been employed as a main source of pine resin in China. To get a better understanding of genetic regulation of resinyielding capacity (RYC), a total of 50 open-pollinated families of masson pine were planted at three testing sites for progeny testing. Investigation was conducted at ages 7, 9, 11, 13, 15, 20, 24 and 26 years to study inheritance, age-age genetic correlation, and early selection efficiency for RYC, height (HT), diameter at breast height (DBH) and volume of individual tree (VOL). Growth characteristics increased gradually with age. RYC had a rapid increase at early ages (before age 15) ficients of variations (CV) for four traits showed a decreasing trend with age and the decreasing rate was rapid at early ages and minor at later ages. Heritability for four traits was relatively stable with minor fluctuation. For across-age classes, heritability was the highest for height, intermediate for RYC, and lowest for volume and DBH. RYC had highly positive genetic correlations with three growth characteristics. Genotype-by-environment interaction for four traits was stronger at Yunan than at other testing sites. Age-age genetic correlations were high for four traits studied, reaching 0.7 after age 9 for most analyses. Early selection at age 13 was highly effective for height, age 15 for DBH and volume, and age 11 for RYC.

Palabras clave

  • Pinus massoniana
  • resin-yielding capacity
  • progeny trial
  • age-age correlation
  • early selection efficiency
Acceso abierto

Mendelian segregation in eight microsatellite loci from hand- and open-pollinated progenies of Araucaria angustifolia (Bert.) O. Kuntze (Araucariaceae)

Publicado en línea: 01 Jul 2017
Páginas: 18 - 24

Resumen

Abstract

In order to use molecular markers in population genetics studies, it is important to confirm that the molecular markers used present a Mendelian segregation. The aim of this paper was to investigate the genetic segregation of eight microsatellite loci of Araucaria angustifolia (Bert.) O. Kuntze (Araucariaceae). The study was carried out comparing genetic segregation in hand- and open-pollinated progenies of maternal dioecious and monoecious trees. The Mendelian segregation was confirmed for all eight loci studied (Ag20, Ag23, Ag45, Aang01, Aang14, Aang28, As90 and CRCAc1), as no deviation from the expected segregation hypothesis was detected in the studied progenies. Therefore, these eight loci can be used for further population genetics studies of A. angustifolia.

Palabras clave

  • Brazilian pine
  • artificial pollination
  • open pollination
  • monoecy
Acceso abierto

Different diversity measures and genetic traits reveal different speciesgenetic diversity relationships: A case study in forest tree communities

Publicado en línea: 01 Jul 2017
Páginas: 25 - 37

Resumen

Abstract

Relationships between species diversity and genetic diversity, the two most important elements of biodiversity, have recently attracted considerable interest in the field of community genetics. The present study contributes to this issue by addressing three questions that seem to have been ignored so far, namely whether the use of (a) different diversity measures, of (b) different components of diversity, and of (c) different genetic traits may lead to different assessements of speciesgenetic diversity relationships. For this purpose, data on species composition and genetic traits were collected from the natural regeneration of nine forest communities, which consist of three pure and six mixed tree stands located in the Thuringian forest area. The genetic traits comprised one DNA (AFLP) and five isozyme traits all of which were determined in all species. In contrast to other studies, the species diversity was determined for two components, SD (species diversity) and NeS (effective number of genetically distinct species), and the genetic diversity was determined for three components, TSGD (the transspecific genetic diversity taken over all species of a community), ISGD and NGS (each describing a special average of intraspecific genetic diversity). Each component was quantified by measures of diversity representing four orders of the Renyi/Hillfamily. The orders correspond to the degree to which prevalence of types is considered in the diversity measure (at the lowest order, known as richness, prevalence is disregarded, with increasing order, the diversity measure reports prevalent types only). In our data, the diversity measured for each genetic trait separately showed a great range of variation across traits and components of diversity even in the same stand. The choice of the diversity component thus turned out to have a substantial effect on the assessment of the level of genetic diversity within stands. This prompted more detailed studies of the relationships between species and genetic diversity. Relationships were quantified with the help of the coefficient of co-variation, and the statistical significance of the co-variations was verified through permutation tests. The co-variations between SD and TSGD were found to be generally positive and in most cases significant, but the co-variation declined with increasing orders of diversity for most of the genetic traits. In contrast, the co-variation between SD and ISGD was not consistent for the four orders of diversity. In particular, the co-variations for the highest order were found to be negative for all traits. The results of our explorative study thus demonstrate that the assessment of levels of genetic diversity within stands as well as species-genetic interrelations critically depend on the choice of the diversity component, of the order of diversity, and of the genetic trait. These observations lend support to different and even opposing hypotheses on the processes potentially generating species-genetic relationships. Therefore, strategies in the conservation of biodiversity, for example, are suggested to be related more specifically to the components and orders of diversity to be safegarded and to consider the functions of genetic traits in relation to adaptationally relevant environmental factors.

Palabras clave

  • co-variation
  • community genetics
  • diversity components
  • genetic diversity
  • genetic traits
  • orders of diversity
  • species diversity
  • forest tree species
Acceso abierto

Genetic Variation and Correlation among Resin Yield, Growth, and Morphologic Traits of Pinus massoniana

Publicado en línea: 01 Jul 2017
Páginas: 38 - 43

Resumen

Abstract

In breeding programs, the variations and relationships among main traits need to be understood to develop selection and breeding strategies. Resin is considered as one of most important non-timber production of P. massoniana which can privides terpenes used in the chemical industry. The present study assessed the genetic variations in growth, morphologic traits, and resin yield, as well as the phenotypic and genetic correlations between these traits of 45 half-sib families of eight-year-old Pinus massoniana trees. All traits show highly significant family effects. The individual heritability for diameter at breast height (DBH) was the highest (hi2=0.55). Heritabilities for resin yield, tree height, crown depth, and the height to the live crown were slightly lower than DBH, ranging from 0.32 to 0.45. The other traits were under weak genetic control and heritabilities ranged from 0.17 to 0.20. All growth and morphologic traits were significantly correlated genetically with resin yield. Number of living branches had the highest genetic correlation with resin yield (rg=0.99), followed by DBH and number of living whorls (rg=0.73 and 0.70). Only a moderate positive genetic correlation with resin yield was found with the other traits (rg=0.47-0.57), except for height under the living branches (rg=-0.45). The results of this study indicate that both resin yield and growth can be improved simultaneously in the next generation. Of the traits assessed DBH was the optimum trait for indirectly selecting high-yielding resin trees.

Palabras clave

  • resin yield
  • growth
  • morphologic traits
  • heritability
  • genetic correlation
  • Pinus massoniana
Acceso abierto

Provenance variation in height development of Albizia falcataria under three levels of spacing in East Java, Indonesia

Publicado en línea: 01 Jul 2017
Páginas: 44 - 51

Resumen

Abstract

Nine provenances of Albizia falcataria were planted at three square spacing levels (2, 3, and 4 m) in a split-plot design at Jember in East Java, Indonesia and measured annually for six years, which is three quarters of its rotation age. The effect of spacing on mean height development became progressively evident, due to the decline in growth at closer spacing caused by intensified competition, in six provenances, i.e., three provenances each from Java and East Indonesia, which were considered better adapted to the site because of their better growth and higher survival. On the contrary, the height growth curves of two provenances from New Guinea were almost identical, irrespective of spacing, indicating a lack of plasticity to the favorable environment at wider spacing. Dominant height was defined as the average of the five tallest trees per sub-plot (350 stems/ha), the growth curves at the three spacing levels were similar in the above-mentioned six provenances and were regarded as a single curve according to AIC-values. In contrast, dominant height growth curves of the New Guinea provenances were differentiated in the order of 2, 3, and 4 m spacing, approximately proportional to the intensity of choosing dominant trees per sub-plot. These results suggest that provenance variation exists for mean and dominant height and their response to different spacing. The cause of this variation was presumably attributable to the difference in competitive ability as well as the plasticity to the given environment. The use of dominant height for growth modeling of A. falcataria was found to be the most suitable for the adapted provenances.

Palabras clave

  • Albizia falcataria
  • height growth curve
  • provenance spacing trial
Acceso abierto

Selection of Poplar Hybrid Clones (Populus ssp.) from Backcrossed Progenies of the Aigeiros Section for Industrial Purpose

Publicado en línea: 01 Jul 2017
Páginas: 52 - 60

Resumen

Abstract

As one of the fast-growing tree species, hybrid poplar (Populus ssp.) has been widely planted in Shandong Province, China. While poplar tree breeding program in the past few decades focused on the development of poplar clones with fast growth rate and disease resistance, little attention was paid to the tree traits of these clones in relation to industrial uses i.e. pulpwood as well as veneer. In this paper, growth performance of hybrid poplar clones from backcrossedprogenies obtained from cross fertilization within the Poplar Aigeiros Section was evaluated and stem traits as well as wood properties in relation to industrial use of some selected clones were assessed. Of the 40 hybrid poplar clones tested in the study, A50 and B69 were prominent in growth rate at three trial sites in Shandong Province, China.Wood properties in relation to industrial uses of the two clones were also better than or comparable to the control clone. It was concluded that A50 is more suitable for pulpwood production while B69 is suitable for a wide range of high value added application such as veneer and plywood. Further research is needed to evaluate the changes of some tree traits in relation to industrial raw materials through time.

Palabras clave

  • Populus
  • Aigeiros
  • controlled pollination
  • growth rate
  • stem traits
  • wood property
  • veneer
  • pulpwood
Acceso abierto

Crossability of Pinus sibirica and P. pumila with their hybrids

Publicado en línea: 01 Jul 2017
Páginas: 61 - 67

Resumen

Abstract

Crossability of Pinus sibirica and P. pumila hybrids and their parental species was studied using the controlled pollination method. Pinus sibirica and its hybrids were represented by grafts at the “Kedr” field station southeast of Tomsk Oblast, Russia; the parental species was of local provenance, with its hybrids obtained from the Southern Baikal region. In the case of P. pumila, trees were pollinated in a wild stand located in the Upper Angara River delta. Parental species had the highest number of filled seeds under open pollination. When they were pollinated with hybrid pollen, the trees showed nearly two-fold reductions in the number of filled seeds. Hybrids tended to abort most ovules during the first year of female cone development, resulting in a high seed abortion rate and consequent low seed production. The number of filled seeds obtained from hybrids was low, with levels ranging from 8.2 to 24.3%. Because of weak reproductive isolation between hybrids and parental species, crosses are inevitable and lead to species introgression. The hybrids probably contribute to interspecies genetic exchange both through hybrid seed production following pollination by parental species and by hybrid pollen distribution.

Palabras clave

  • hybridization
  • Pinus sibirica
  • P. pumila
  • controlled pollination
  • reproductive isolation
Acceso abierto

Computer Simulation for the Evaluation of Recombination Strategies in Intrapopulation Recurrent Selection in Eucalyptus

Publicado en línea: 01 Jul 2017
Páginas: 68 - 79

Resumen

Abstract

Intrapopulation recurrent selection (IRS) has proven to be a promising breeding method in eucalyptus, mainly through being easier to carry out when compared to reciprocal recurrent selection (RRS). However, the recombination strategies in IRS that have not yet been compared. Thus, the purpose of this study was to verify the efficiency of different recombination methods in IRS. To do so, computer simulation was used considering different heritabilities (0.1, 0.5, 1.0), different initial allelic frequencies (0.2, 0.8) and allelic interactions without dominance and with complete dominance. The initial population consisted of 1000 individuals, which were selected at random for the beginning of cycle zero. These individuals were interbred two by two. Three selection strategies were carried out and, consequently, three recombination methods: recombine the best individuals selected within the best progenies; the best individuals phenotypically selected regardless of their genealogy; or selection in the mean value of the best progenies selected. It was observed that recombination of the best individuals regardless of their genealogy and of the best individuals within the best progenies provided for gains superior to recombination having only the mean of the progenies as reference. The average degree of dominance and the heritability of the trait should be considered at the time of choosing the method of selection followed by recombination.

Palabras clave

  • Forest breeding
  • Quantitative Genetics
  • Monte Carlo
  • Breeding Strategies
  • Genetic Gain
Acceso abierto

Variability in Wild Germplasm of Natural Rubber (Hevea brasiliensis Muell. Arg.)

Publicado en línea: 01 Jul 2017
Páginas: 81 - 85

Resumen

Abstract

Para rubber (Hevea brasiliensis), a native of the Amazon forests of South America, is the chief source of natural rubber in the world. With the objective of broadening the original gene pool collected by Sir Henry Wickham in 1876, the International Rubber Research and Development Board (IRRDB) made a large collection of wild germplasm from Acre, Rondonia and Mato Grosso states of Brazil in 1981, which was distributed to various member countries including India for conservation and evaluation. In the present study, variability was assessed in a set of 195 Hevea accessions belonging to the wild gene pool in India, using 22 characterization descriptors and eight quantitative growth characters in the juvenile stage. The Shannon-Weaver diversity indices worked out for each of the 22 qualitative traits indicated a high level of diversity in the collection. The range of variation for quantitative traits viz., plant height (0.43 to 3.16 m), basal diameter (0.81 to 2.52 cm), number of whorls (1.23 to 5.48), inter-node length (4.11 to 45.26 cm), number of leaves (11.44 to 91.26), single leaf area (80.22 to 223.57 cm2), total leaf area (2356.00 to 14660.50 cm2) and leaf area index (0.24 to 1.47), also represented wide variability in the collection. The accessions were ranked for overall performance and top 10% were selected for early growth vigour. The high level of variability observed in this germplasm indicates its potential use in crop improvement programmes and for broadening the genetic base of Hevea.

Palabras clave

  • Hevea brasiliensis
  • Shannon-Weaver diversity index
  • wild rubber germplasm
Acceso abierto

Clinal variation in Pinus hartwegii populations and its application for adaptation to climate change

Publicado en línea: 01 Jul 2017
Páginas: 86 - 95

Resumen

Abstract

In order to determine the genetic variation among populations of Pinus hartwegii along altitudinal gradients, and the possible adaptive decoupling due to climatic change, a common garden test was set up with 13 provenances collected along an altitudinal transect (3150 to 3750 masl; collection sites were every 50 m of altitudinal difference) from Pico de Tancítaro, Michoacán, west-central Mexico. The test evaluated trees aged 4.5 to 5.5 years, and contemporary and future (year 2030; six model-emission scenarios) climate variables were estimated. We found significant (P<0.005) differences among populations in total elongation, final seedling height, basal diameter, rate of elongation, dry weight of needles, branches and stem, total dry weight and first principal component. We found a significant association between population performance, expressed as first principal component values, and their climate, where the best climatic predictor was the frost free period (r2=0.90, P<0.0001). This result indicates that the patterning of genetic differentiation among populations is strongly associated with a climatic and altitudinal gradient. We propose a re-delineation of fixed climatic and altitudinal seed zoning for seed and seedling movement, based on intervals of 26 days of difference of frost free period: Zone 1, from 240 to 214 days of frost free period or 12 to 11°C or 3150 to 3350 masl; Zone 2, 214 to 188 days or 11 to 10°C or 3350 to 3550 masl; and Zone 3, 188 to 162 days or 10 to 9°C or 3550 a 3750 masl. Projecting at what altitude will occur the same frost free period values by year 2030, we suggested that populations should be shifted 400 m attitudinally upward, through a program of assisted migration, aiming to realign the populations to the climate for which they are adapted. Seedling deployment should use future (year 2030) fixed seed zones, with the same projected climatic interval values than contemporary climate, although at the following altitudinal limits: Zone 12030, from 3550 to 3750 masl; Zone 22030, 3750 to 3950 masl; and Zone 32030, 3950 to 4150 masl.

Palabras clave

  • Pinus hartwegii
  • provenance
  • altitudinal genetic variation
  • seedling height
  • shoot elongation
  • dry weight
  • climatic change
  • zoning
  • assisted migration
Acceso abierto

Anatomical and Physiological Effects of Phytohormones on Adventitious Roots Development in Larix kaempferi × L. olgensis

Publicado en línea: 01 Jul 2017
Páginas: 96 - 103

Resumen

Abstract

Adventitious root development is crucial for cutting propagation in hybrid larch. In the present study, semilignified cuttings of Larix kaempferi × L. olgensis clones were used to study the morphological and anatomical changes during the different development stages and compare the changes in contents of endogenous phytohormone in two clones with evidently different rooting capacity (25-5 and 23-12), and the effects of exogenous Indole-3-Butyric Acid (IBA) on phytohormone content of a very low native rooting capacity clone (8-9) during the development of adventitious roots. The results showed that the development of adventitious root in semi-lignified cuttings involves three key stages: root cell dedifferentiation and division (14-18 DAC); meristem formation and development (25-35 DAC); root formation and elongation (50-55 DAC). The endogenous phytohormones play a key role during adventitious root development. For 25-5 and 23-12, the level of endogenous phytohormones, especially the ABA content, has an important effect on rooting capacity. For the effects of IBA on 8-9, except lower ABA content, the temporary peak of IAA on the 1 DAC was important for initiating the rooting process. The ratio of (IAA + GA3 + ZR)/ABA can be used as an indicator of rooting capacity. The anatomical and physiological data described here for semi-lignified cuttings of L. kaempferi × L. olgensis clones improves our knowledge of adventitious roots development. Our study will also benefit future research on examining the molecular mechanisms of the adventitious roots development in hybrid larch.

Palabras clave

  • anatomy
  • IBA
  • phytohormone ratio
  • adventitious roots
  • rooting capacity
  • Larix kaempferi × L. olgensis
Acceso abierto

Primer Note: A novel set of EST-SSR markers in Tamarix: a resource to characterize this genus

Publicado en línea: 01 Jul 2017
Páginas: 104 - 109

Resumen

Abstract

Both the negative and positive ecological impact of Tamarix plants is controversial, and thus a more comprehensive understanding is necessary. Tamarisks are invasive in many countries but the inter-specific transferability that characterizes simple sequence repeats (SSRs) could be harnessed to track the spread of specific genotypes or to study invasive populations. Thirteen polymorphic SSR markers, derived from expressed sequence tag (EST), were identified by first screening 26 samples of T. aphylla, T. jordanis, T. nilotica, and T. tetragyna and then 33 unidentified tamarisks from Yotvata, Israel. The mean number of alleles per locus ranged from two to 14 and the mean expected heterozygosity was 0.415. These EST-SSR markers will undoubtedly be useful in the genetic characterization of the genus Tamarix due to their high cross-species transferability which enables the estimation of the genetic diversity among and within different species, that are adapted to the same desert habitat under severe environmental constraints.

Palabras clave

  • Tamarisk
  • species identification
  • microsatellite
  • Bayesian assignment method
Acceso abierto

Genetic parameters for early growth and biomass traits of Pinus radiata D. Don under different water regimes

Publicado en línea: 01 Jul 2017
Páginas: 110 - 116

Resumen

Abstract

In Chile, genetic improvement of Radiata pine has been directed towards characters such as volume, form and wood density. Estimation of genetic parameters for growth and biomass traits in young seedlings, as a tool for early indirect selection in the P. radiata breeding program, has not been explored yet. We aimed to estimate genetic parameters for growth and biomass traits. Five-month-old P. radiata seedlings grown under wellwatered (WW) and water stress (WS) regimes were evaluated. Root collar diameter, height, shoot dry weight, root dry weight, total dry weight, height/diameter ratio and root/shoot ratio were analyzed in both treatments. Trait with the highest heritability was root/shoot ratio in WW and WS regime (h2 = 0.80 and 0.63 respectively). The highest genetic correlation was between height and shoot dry weight (rg = 0.90), under WW regime. In contrast, there were negative genetic correlations between root collar diameter and height/diameter ratio under WS regime. To breed for drought tolerance, traits such as height and root collar diameter would be effective targets for indirect selection since estimated heritabilities are high, there is sizable genetic variation, they are easily assessed, they can be measured non-destructively and they have a high genetic correlation with root/shoot ratio, a trait related to drought tolerance. The measurement of dry weights for early selection purposes is not recommended.

Palabras clave

  • heritability
  • genetic and phenotypic correlation
  • Type B correlation
  • Pinus radiata
  • water stress
  • biomass
Acceso abierto

Aspects of sexual reproduction in rare monoecious Populus nigra var. nigra trees

Publicado en línea: 01 Jul 2017
Páginas: 117 - 123

Resumen

Abstract

Individuals of the genus Populus are mostly dioecious, although deviations from strict dioecism occasionally occur. The aim of this study was to determine whether six, rare monoecious Populus nigra var. nigra trees, identified in trial plots, were fertile and capable of sexually reproducing. Controlled pollinations were carried out and compared with the results of open pollination. Viable seeds were obtained from all combinations of pollination possibilities, suggesting these monoecious trees could be used as either male or female parent and were self-fertile. However, no individuals produced by selfpollination were found among the offspring from openpollinated, monoecious trees. The parentage of some of the crosses was verified using microsatellite markers. The germination energy (GE) and germination capacity (GC) were in most cases higher for seeds produced from controlled pollinations than from open pollination. Furthermore, GE and GC were both higher when pollen from the monoecious trees was used. An association between GE and GC rates on the one hand, and the pollination method and year it took place on the other, was found in most crosses made. This study extends knowledge of the reproductive biology of P. nigra that could be utilized in conservation genetic of this endangered allogamous species.

Palabras clave

  • Black poplar
  • germination capacity
  • germination energy
  • microsatellite markers
  • monoecism
  • paternity
  • controlled pollination
Acceso abierto

Short Note: Development and characterization of 16 new polymorphic microsatellite loci for Schima superba (Theaceae)

Publicado en línea: 01 Jul 2017
Páginas: 124 - 126

Resumen

Abstract

Schima superba is a common dominant tree species in evergreen broad-leaved forest in subtropical China. Despite its multiple usages in wood industry, reforestation and traditional Chinese medicine, its genetic diversity is poorly studied. To help studying its genetic diversity and structure in the future, after microsatellite enrichment and screening, we identified 16 microsatellites in S. superba. These markers showed polymorphism in three populations. The number of alleles per locus ranged from 3 to 32 with a mean of 14. Within populations, the observed and unbiased expected heterozygosities ranged from 0.048 to 0.926 and from 0.048 to 0.949, respectively. The newly developed 16 microsatellites will be useful for investigating the genetic diversity and structure from large scale patterns to fine-scale structures in this species.

Palabras clave

  • DHS plot
  • DNA enriched libraries
  • genetic marker
  • genetic variation
  • Hardy-Weinberg equilibrium
  • linkage disequilibrium
  • marker development
  • microsatellite
  • population genetics
  • reforestation
  • spatial genetic structure
  • subtropical China
Acceso abierto

Genetic status of Norway spruce (Picea abies) breeding populations for northern Sweden

Publicado en línea: 01 Jul 2017
Páginas: 127 - 136

Resumen

Abstract

Efficient use of any breeding resources requires a good understanding of the genetic value of the founder breeding materials for predicting the gain and diversity in future generations. This study evaluates the distribution of genetic variation and level of relatedness among and within nine breeding populations of Norway spruce for Northern Sweden using nuclear microsatellite markers. A sample set of 456 individuals selected from 140 stands were genotyped with 15 SSR loci. Over all loci each individual was identified with unique multilocus genotype. High genetic diversity (average He=0.820) and low population differentiation (FST=0.0087) characterized this material. Although low in FST, the two northernmost populations were clustered as a distinct group diverged from the central populations. The population differentiation pattern corresponds well with the post glacial migration history of Norway spruce and the current gene flow and human activity in the region. The average inbreeding coefficient was 0.084 after removal loci with high frequency of null alleles. The estimated relatedness of the trees gathered in the breeding populations was very low (average kinship coefficient 0.0077) and not structured. The high genetic variation and low and not structured relatedness between individuals found in the breeding populations confirm that the Norway spruce breeding stock for northern Sweden represent valuable genetic resources for both long-term breeding and conservation programs.

Palabras clave

  • breeding stock
  • genetic diversity
  • long-term breeding
  • population subdivision
  • relatedness
Acceso abierto

Development and characterization of 28 polymorphic EST-SSR markers for Cunninghamia lanceolata (Taxodiaceae) based on transcriptome sequences

Publicado en línea: 01 Jul 2017
Páginas: 137 - 141

Resumen

Abstract

The Chinese fir (Cunninghamia lanceolata) is a very important plantation species that is mainly distributed in Southern China. However, genomic analyses of C. lanceolata have lagged significantly behind those of other conifer species due to a lack of suitable markers. To address this issue, we examined 27,666,670 reads from C. lanceolata transcriptome sequences recorded in the SRA database. Assembly produced 35,633 contigs, 1,822 (5.11%) of which contained one or more SSRs. In total, 2,156 SSRs were identified, giving an average SSR density of 68.4 SSRs/Mb. The most common SSR types were tri-SSRs (41.7%), followed by hexa-(29.8%), penta- (12.7%), di-(11.1%) and tetra-(4.7%) SSRs. EST-SSR markers based on the 1,822 SSR-containing contigs were developed using the CMiB pipeline and primer pairs were designed to target 35 loci. Polymorphism was observed in 28 of these loci, for which the number of alleles per locus ranged from 3 to 12 over 16 plus-tree individuals. The observed heterozygosity (Ho), expected heterozygosity (He) and fixation index (FIS) values for the targeted loci ranged from 0.125 to 0.938, 0.225 to 0.891 and -0.368 to 0.456, respectively. The corres - ponding PIC values ranged from 0.210 to 0.881, with an average of 0.573. Some of these markers have since been used in our ongoing genetic diversity analyses of C. lanceolata. To our knowledge, this is the first analysis of SSRs and EST-SSR markers in C. lanceolata, and the identified EST-SSR markers will be useful in future genetic analyses of C. lanceolata and related species.

Palabras clave

  • Cunninghamia lanceolata
  • expressed sequence tag
  • microsatellite markers
  • de novo assembly
  • transcriptome sequences
Acceso abierto

Wood physical properties, color, decay resistance and stiffness in Tectona grandis clones with evidence of genetic control

Publicado en línea: 01 Jul 2017
Páginas: 142 - 152

Resumen

Abstract

Tectona grandis (teak) plantations are being produced with trees from genetic improvement programs, including clonal selection. However, limited information about inheritance of wood properties is available. For studying genetic parameters of T. grandis wood properties and stem diameter two 10-yr-old trials were studied involving nominally 2 sites × 20 clones × 3 replicates × 1 ramet. Clonal variation was observed in: heartwood (HWP), pith (PP) and bark (BP) percentages; green moisture content (IMC) and density (GD); tangential (TS), radial (RS) and volumetric (VS) shrinkage and ratio tangential/radial: shrinkage (ratio T/R); L*a*b* color parameters; and stiffness and specify gravity (SG). Some wood properties evidenced strong across-sites genotypic control. The higher broad-sense heritability estimates (over 0.36) were for PP, IMC, SG, TS, VS and L*, a*, and b* color coordinates and stiffness. Low and non-significant values were estimated for HWP, BP, GD, RS, ratio T/R and decay resistance of sapwood and heartwood to Trametes versicolor and Pycnoporus sanguineus. However, HWP showed marked clone x site interaction. Phenotypic and tentatively estimated genotypic correlations indicate that selecting faster-growing clones will improve some important wood properties, such as increasing HWP, and decreasing PP and BP, without affecting other wood properties. Selecting clones for denser wood, as expected, improved stiffness, should decrease IMC and affect negatively b* (yellow/blue) color. Clone selection with lower L* values could increase redness (a*) of wood.

Palabras clave

  • teak
  • genetic parameters
  • broad-sense heritability
  • genotypic correlations
  • wood properties
  • heartwood color
  • wood decay
Acceso abierto

Growth and breeding of aspen in Russia

Publicado en línea: 01 Jul 2017
Páginas: 153 - 160

Resumen

Abstract

Researches results are presented that describe variation in natural aspen stands and hybrid collections in Central European Russia. The subject of the study was the selection of the most productive and resistant to heart rot caused by fungus Phellinus tremulae (Fomes

igniarius) stands. Mechanical wood properties, fodder values and other valuable characteristics of aspen are also shown. The valuable stands and hybrids which require conservation were selected for breeding and practical use.

Palabras clave

  • aspen
  • heart rot resistant
  • breeding
  • hybrids
  • forms
  • mechanical properties
  • fodder value
Acceso abierto

Characterization of genes expressed in Casuarina equisetifolia in response to elicitation by cell wall components of Trichosporium vesiculosum

Publicado en línea: 01 Jul 2017
Páginas: 161 - 172

Resumen

Abstract

Casuarina equisetifolia has the widest distribution of all Casuarina species and is a nitrogen-fixing tree planted in tropical/subtropical littoral zones of Asia, the Pacific and Africa for coastal reclamation, charcoal making, pulp and timber. Trichosporium vesiculosum, the causal agent of blister bark disease, is a serious pathogen of C. equisetifolia. The present study was undertaken to understand the molecular mechanisms involved during pathogen cell wall elicitation in this hardy tree species. Transcript profiling during elicitation induced by cell wall components of T. vesiculosum revealed expression of resistance genes; cytochrome oxidase; trans membrane proteins; genes involved in programmed cell death like 26S proteasome and ubiquitin activating enzyme; early nodulin gene, wound inducible metallocarboxy peptidase inhibitor, glucanase, metal binding protein and signal recognition particle. The fold expression of selected transcripts including glucanase, 26 S proteasome, signal recognition particle, cytochrome oxidase and the metal binding protein using RT-qPCR revealed 12-59 fold increase in expression after 48 hours of elicitor treatment. The expression of these transcripts during abiotic stresses like heat, mechanical wounding, salt (NaCl) and drought (PEG) was also analyzed. Glucanase was up-regulated significantly during wounding and heat stress while proteasome was up-regulated 1-4 fold during NaCl, PEG and wounding stress. The novel transcript CeHMA was up-regulated under all the stress conditions. This is the first report on molecular defense in C. equisetifolia and has provided a pool of candidate genes for detailed molecular dissection to further broaden the knowledge on the response of woody perennials during pathogen cell wall elicitation.

Palabras clave

  • Abiotic stress
  • elicitor treatment
  • transcript profiling
  • tree defense
Acceso abierto

Genetic analysis and clonal stability of two yellow cypress clonal populations in British Columbia

Publicado en línea: 01 Jul 2017
Páginas: 173 - 186

Resumen

Abstract

Genetic analysis of height and form at age 12 years of 697 yellow cypress (Callitropsis nootkatensis [D. Don] Oerst.) clones tested across seven sites in coastal British Columbia (BC) were explored in populations: Population 1 - No Pedigree and Population 2 - Reconstructed Pedigree. Genetic variances were statistically significant but generally higher σ̂g2 was observed for Population 2. Height and form were under low to moderate genetic control as indicated by clonal repeatability and estimates were relatively similar between populations. For example, average Ĥ2 in Population 2 was 0.31 for height (range: 0.18-0.45) and 0.22 for form (range: 0.06-0.32). While average Ĥ2 in Population 1 was 0.25 for height (range: 0.19-0.35) and 0.18 for form (range: 0.09-0.27). The reconstructed pedigree in Population 2 allowed partitioning the genetic variance (σ̂g2) into component parts of additive (σ̂a2), specific combining ability (σ̂s2 ), and clone (σ̂c2 ); however, general lack of structure within the population resulted in variance components to be estimated with little precision for additive and specific combining ability. The majority of genetic variation was associated with clone for both traits. For example, σ̂c2 accounted for 57.6% and 62.5% of the total genetic variance for height and form, respectively. Growth and form responses of clones across test environments were relatively stable and overall type-B genetic correlations were in excess of 0.8 for both traits implying clones selected for production populations should respond favorably across the seed planning zone for yellow cypress in coastal BC.

Palabras clave

  • Yellow cypress
  • clones
  • genetic testing
  • genotype x environment
  • clonal repeatability
Acceso abierto

Analyses of Genotypic Variation in White Poplar Clones at Four Sites in China

Publicado en línea: 01 Jul 2017
Páginas: 187 - 195

Resumen

Abstract

Growth characteristics have a complex inheritance pattern, and the gene-environment interaction makes predicting tree responses to environmental change difficult. The primary goals of this study are to evaluate the variation in growth traits of different white poplar clones and to measure the inter-site variation and ecological sensitivities. In the experiment, a total of 30 white poplar clones were planted and measured over 5 years for height (H) and diameter at breast height (DBH) at four different sites in North China. ANOVA results showed that there were significant differences in H and DBH between clones at each site (P<0.01). Phenotypic and genotypic variation, and the repeatability of H and DBH, increased with the tree growth, which suggested that the inter-clone variation became gradually larger under the control of genetic factors. Under a selection ratio of 20%, the genetic gains of H and DBH also increased with the tree growth at the same site. Correlation analysis showed a significantly positive association between H and DBH both at the same age and sites, but the correlation coefficients decreased with increasing age. In conclusion, genetic gains were not equal between different sites, indicating differences in the influence of environment on the poplar genotype. Further investigations may be able to determine the role of environment for tree breeding programs and genetic selection.

Palabras clave

  • poplar
  • variation
  • repeatability
  • genetic gain
Acceso abierto

Growth differences and genetic parameter estimates of 15 teak (Tectona grandis L.f.) genotypes of various ages clonally propagated by microcuttings and planted under humid tropical conditions

Publicado en línea: 01 Jul 2017
Páginas: 196 - 206

Resumen

Abstract

Fifteen clones of teak (Tectona grandis) produced by micropropagation from 0.5 to more than 60 yr-old selected ortets were established in a clonal test in Sabah (East Malaysia) under 2500 mm of annual rainfall to compare their growth performances during the first 7 years of development. Field establishment was good with average mortality less than 10%. The clones developed rapidly true-to-type with significant between-clone differences in growth. Ranges of clone means were 13.6 to 19.3 m in height, 16.3 to 23.4 cm in diameter at breast height (DBH) and 129 to 264 dm3 in volume. Broad sense heritability estimates for these growth traits were lower overall for single trees (H2i) than for clone means (H2c) (H2i ≤ 0.257 vs H2c ≤ 0.634 for height, H2i ≤ 0.120 vs H2c ≤ 0.383 for DBH and H2i ≤ 0.125 vs H2c ≤ 0.364 for volume). The highest genetic gain that could be expected from the best three clones out of the fifteen compared was at age 2 for height (+0.66 m, or +11.7%), and age 3 for DBH (+0.87cm, or +10.4%) and volume (+4.65 dm3, or +15.7%). Age-related phenotypic correlation values were reliably (P < 0.0001) higher and more consistent for DBH (rP ≥ 0.61) than for height (0.37 ≤ rP ≤ 0.69), or than between DBH and height, except for height at 3 (0.51 ≤ rP ≤ 0.63) and 6 (0.55 ≤ rP ≤ 0.69) years. Height and DBH were moderately to highly genetically correlated (0.54 ≤ rG ≤ 0.90).

Palabras clave

  • broad sense heritability
  • clone
  • genetic correlations
  • genetic gain
  • growth
  • maturation
  • rejuvenation
  • vegetative propagation
Acceso abierto

Isolation and characterization of chloroplast microsatellite markers in the invasive tree species Robinia pseudoacacia L.

Publicado en línea: 01 Jul 2017
Páginas: 207 - 209

Resumen

Abstract

Robinia pseudoacacia is one of the most problematic invasive alien species in Japan. Information on genetic diversity and population structure is urgently required in order to generate effective management strategies. To assist such efforts we have identified five chloroplast microsatellite (cpSSR) markers for R. pseudoacacia by amplifying noncording regions of chloroplast DNA (cpDNA) using universal chloroplast primers. Among 857 individuals these cpSSR markers showed substantial polymorphism, with three to eight alleles per locus and gene diversity ranging from 0.387 to 0.713. These cpSSR makers will be useful for analyzing maternal lineages and population genetic structure of R. pseudo - acacia.

Palabras clave

  • cpSSR
  • Maternal lineage
  • Black locust
Acceso abierto

Induction of Quercus ilex L. haploid and doubled-haploid embryos from anther cultures by temperature-stress

Publicado en línea: 01 Jul 2017
Páginas: 210 - 217

Resumen

Abstract

This paper describes a method to obtain haploid and doubled-haploid (DH) embryos using anther cultures of holm oak (Quercus ilex L.). The production of haploids and DH through gametic embryogenesis provides an attractive biotechnological tool for developing homozygous lines from heterozygous parents, which is important in breeding programs, as well as in genetic studies. As a consequence, protocols to produce homozygous plants have a significant impact on forest tree improvement. Anthers were subjected to different temperature treatments for embryo induction: a cold pre-treatment (4°C) from 3 to 7 days was carried out at the beginning, followed by a heat shock (33°C) from 2 to 5 days. Most anthers responding to these stress treatments contained vacuolated microspores, indicating that this developmental stage is responsive to embryogenesis induction in holm-oak microspores. In all cases, embryos grew from the interior of the anthers, breaking through the degenerating anther walls. Under these conditions, embryo formation occurred in 31 anthers between 46 and 95 days after culture initiation. Embryo analysis performed with flow-cytometry and DNA-microsatellite markers showed haploid profiles and/or spontaneous doubling of the chromosomes during early regeneration stages. This is, to our knowledge, the first published report on gametic embryogenesis in holm oak.

Palabras clave

  • anthers
  • holm oak
  • microsatellite DNA-markers
  • pollen embryogenesis
  • Quercus ilex
Acceso abierto

Genetic variation and genetic gain in growth traits, stem-branch characteristics and wood properties and their relationships to Eucalyptus urophylla clones

Publicado en línea: 01 Jul 2017
Páginas: 218 - 231

Resumen

Abstract

Growth traits, wood properties, stem-branch characteristics and bark percentage were assessed for 60 Eucalyptus urophylla S.T. Blake clones in southern China measured at age 21, 52, 71 and 96 months. Analysis of variance showed that there were significant differences on growth traits, wood properties and individual tree wood weight among clones. Coefficients of genotypic variation ranged from 12.12% to 53.16% for growth traits, 9.02% to 20.18% for wood properties, 21.75% to 22.71% for stem-branch characteristics, 28.31% for bark percentage and 51.20% for individual tree wood weight. Repeatability ranged from 0.36 to 0.53 for growth traits, 0.35 to 0.51 for wood properties, 0.21 to 0.24 for stembranch characteristics, 0.07 for bark percentage and 0.31 for individual tree wood weight. The strongly negative genotypic correlations suggesting that selection on growth traits at 21 months can not be effective to predict growth traits at 96 months whereas it could be used to predict growth traits at 52 and 71 months. The genotypic correlations between growth traits and basic density were ranged from -0.78 to 0.28 and weakly positive phenotypic correlations were found between growth traits and basic density, ranging from 0.03 to 0.09. The selection gain on diameter at breast height over bark by different selection proportions at 21, 52, 71 and 96 months old expressed that selection gain at 71 months was some what higher than that at other ages during 10% to 30% selection proportion, while selection gain at 52 months was some what higher than that at other ages during 60% to 90% selection proportion. Wood properties and individual tree wood weight which are strongly related to end production and economically important in pulp production should be studied extensively especially for pulp breeding.

Palabras clave

  • multiple traits
  • nondestructive evaluation
  • individual tree wood weight
  • repeatability
  • age trend
  • simple weighting coefficient method
Acceso abierto

Using portfolio theory to improve yield and reduce risk in black spruce family reforestation

Publicado en línea: 01 Jul 2017
Páginas: 232 - 238

Resumen

Abstract

Family forestry, defined as the deployment of families in mixture into plantations, is becoming an attractive option for black spruce (Picea mariana (Mill.) BSP) in New Brunswick, Canada. With many elite families of black spruce being available, there is a knowledge gap regarding how to compose a mixture of families that optimally balances the objectives of increased yield and reduced risk. This study, based on real field test data, investigates the application of a model based on the modern portfolio theory to optimally balance yield and risk when selecting a portfolio (mixture) of black spruce families to deploy in reforestation. The risk was expressed as the variance of the family portfolio, an effective indicator of yield stability. This is an innovative approach in forestry and it is compared to the currently used method, truncation-deployment, defined as the equal deployment of seed of selected families. Results show that the portfolio theory searched for the combination of yield and stability and produced family portfolios maximizing yield at a given stability or minimizing yield instability at a given yield. The portfolio theory was never inferior in maximizing yield to the truncation- deployment approach when yield stability is a concern. We recommend using portfolio theory to determine family portfolios for family forestry. While this study targets to family forestry, the results may be relevant to other deployment strategies where stability is a concern, such as clonal forestry.

Palabras clave

  • family forestry
  • portfolio theory
  • yield stability
  • tree improvement
  • black spruce
Acceso abierto

Identification of upregulated genes in laminarin-treated poplar (Populus alba × P. tremula var. glandulosa) suspension cells by suppression subtractive hybridization and cDNA microarray

Publicado en línea: 01 Jul 2017
Páginas: 239 - 245

Resumen

Abstract

Elicitors trigger defence responses in plant cells through signal transduction pathways, leading to accumulation of pathogenesis-related (PR) proteins and, eventually, pathogen resistance. To understand defence responses of hybrid poplar (Populus alba × P. tremula var. glandulosa), we isolated and characterized upregulated genes in poplar cells by laminarin-induced elicitation using suppression subtractive hybridization (SSH) and cDNA microarray approaches. A total of 1,269 clones in the SSH library were sequenced and a cDNA microarray, containing 265 unique subtracted clones, was fabricated. From the microarray results, 37 clones were found to be upregulated by laminarin treatment and their putative functions are discussed. Genes involved in signal transduction, transcriptional regulation, and phytohormone biosynthesis were upregulated. Other genes encoding PR proteins, peptidases, and an ABC transporter, as well as genes involved in lignification and protein synthesis and turnover, were also identified. Our results suggest that well-organized defence responses, from signal transduction to accumulation of PR proteins, are activated in poplar cells by laminarininduced elicitation and could contribute to resistance against pathogens.

Palabras clave

  • Elicitor
  • Gene expression
  • Laminarin
  • Microarray
  • Poplar
Acceso abierto

Microsatellite markers for Eucalyptus pilularis (Subgenus Eucalyptus); sourcing genetic markers outside the subgenus

Publicado en línea: 01 Jul 2017
Páginas: 246 - 255

Resumen

Abstract

Microsatellite markers remain the most broadly used molecular marker in eucalypt genetics. A major advantage of microsatellite markers is that they often transfer readily between related taxa circumventing the need to develop new markers de novo in each species. Markers have been developed for a number of species of major economic importance, mainly from the Subgenus Symphyomyrtus, but these may also be available for use in species of lesser economic importance from other subgenera. Here we report on the sourcing of microsatellite markers for E. pilularis (Subgenus Eucalyptus (Formerly Monocalyptus)) from species outside the subgenus. Ninety-seven precent (60 out of 62) of loci that amplified in the source taxon (E. grandis) also amplified in the target taxon E. pilularis. By characterising them on a diversity panel (n=24) and a pedigree, a subset of 41 loci were distilled out that could be scored reliably and were polymorphic (Mean unbiased heterozygosity= 0.81). Predictions of efficient microsatellite marker transfer among eucalypts based on low evolutionary divergence have largely been borne out and are congruent with accumulating evidence of low sequence divergence within Eucalyptus. Upon this favourable background for microsatellite marker transfer, this study indicates highly efficient transfer is possible by identifying loci with broad PCR optima and adoption of approaches that favour cross-species transfer.

Palabras clave

  • Monocalyptus
  • Eucalyptus
  • Symphyomyrtus
  • genetic diversity
  • microsatellite marker
  • internal transcribed spacer
  • ITS CCR
Acceso abierto

Variation in seed traits and oil content in 24 Jatropha curcas L. seed sources from Asia, Africa and Papua New Guinea

Publicado en línea: 01 Jul 2017
Páginas: 257 - 264

Resumen

Abstract

This study was carried out to determine the extent of variation in seed traits and oil content among 24 seeds sources of Jatropha curcas from 8 countries in Asia, Africa and Papua New Guinea. There were marked differences in the length (range 15.88-19 mm), breadth (10.20-11.71 mm), thickness (7.95-9.37 mm) and volume index of seed (1337-2000 mm3), weight of seed (42.67-80.20 g) and kernel (18.44-51.04 g), kernel/seed ratio (0.43-0.66), and oil content in seed (18.08-37.89%) and kernel (34.02-59.09%). In general, seeds from Laos, Mali, Papua New Guinea, Philippines and Thailand were larger and heavier than sources from China and India, but contained lower oil content in seed and kernel. Principal component analysis revealed that seed and kernel weight and oil content in whole seed and in kernel were useful characteristics in explaining the variation pattern among seed sources. Seven out of the 24 seed sources investigated in this study are considered promising for planting for oil-seed production. This study underpins the importance of selecting suitable seed sources for commercial plantation establishment of J. curcas.

Palabras clave

  • Jatropha curcas L.
  • biofuel
  • seed size parameters
  • seed oil content
  • principal component analysis
Acceso abierto

Genetic Variation in Wood Property and Growth of Taiwania (Taiwania cryptomerioides Hayata)

Publicado en línea: 01 Jul 2017
Páginas: 265 - 276

Resumen

Abstract

The genetic variation in wood property and growth of Taiwania (Taiwania cryptomerioides) was investigated at two test sites in the same general location, but one at 1200 m (LK20) and another at 1900 m (LK24). A rangewide sample of 48 open-pollinated families in Taiwan was involved. The test plantations were 16 years old when the wood property data were collected. Traits studied include wood specific gravity, tracheid length, ring width. DBH at ages13, 16, and 22 and height at age 13 were also analyzed. Site environment had a dominant effect on growth and wood density, but showed little interaction with family. The site effect was evident in large between-site differences in means, range of family means, and size of family variance components and heritability estimates. These differences are attributable to the site characteristics of LK24 (high elevation, upper slope near a mountain crest) and an unfavourable local climate. Taiwania is fast growing and produces quality wood, and is also an interesting species from the perspective of evolutionary biology. Protection of its genetic variability should be a priority to be managed. We propose that the existing five progeny tests be protected since these tests well-represent the genetic variability of the species in Taiwan.

Palabras clave

  • Taiwania cryptomerioides
  • genetic variation
  • site effect
  • Taiwan
Acceso abierto

Genetic parameters and efficiency of early selection for half rotation-aged growth and form traits in Pinus taeda in China

Publicado en línea: 01 Jul 2017
Páginas: 277 - 284

Resumen

Abstract

Genetic parameters for height (H), diameter at breast height (DBH), stem straightness (STR), and under crown clear bole height (CH) of loblolly pine (Pinus taeda L.) were estimated for 255 families (209 open pollinated (OP) and 46 controlled pollinated (CP) families) using a family model and an individual tree model at age 1, 2, 3, 5, 11, and 15 years. Heritability estimates for growth traits of individual trees at age 11 years were the highest (0.17-0.78), and those at age 15 years were the lowest (0.05-0.74). Heritability estimates for DBH, STR, and CH were lower than those for H. Genetic correlations between H and DBH were generally strongly positive, attained a maximum values at age 2 to 3, and declined slightly thereafter. The genetic correlations between CH at age 11 and both H and DBH at different ages were moderate. Age-age genetic correlations for growth traits were moderate to high (0.56-0.91) at age 5 for half-rotation age (15 years), indicating the opportunity exists for early selection. Indirect selection from the age 5 to 11 years for H and DBH could be expected to produce gains of over 50% and 35% respectively, for these two ages, relative to direct selection at age 15. Efficiencies of early selection for H and DBH indicated that growth at maturity could be improved by early selection.

Palabras clave

  • age-age correlation
  • genetic correlation
  • genetic gain
  • height
  • heritability
  • Pinus taeda
Acceso abierto

Occurrence and cytological mechanism of numerically unreduced pollen in diploid Populus euphratica

Publicado en línea: 01 Jul 2017
Páginas: 285 - 291

Resumen

Abstract

Unreduced gametes are the driving force for the polyploidizaiton of plants in nature, and are also an important tool for breeding of triploid individuals. The final heterozygosity of a 2n pollen grain depends on the cytological mechanism behind 2n pollen formation. In this study, meiotic abnormalities were analysed using fluorescent chromosome staining and indirect immunofluorescence during the microsporogenesis of 18 genotypes of diploid P. euphratica Oliv. (2n = 2x = 38). Among the 18 genotypes, 16 genotypes produce 2n pollen and two genotypes produce only normal n pollen. In all 2n pollen producers, we found that the first meiotic division was normal but that the second division was characterized by frequent abnormal spindle orientation (parallel, tripolar, and fused spindles) and premature cytokinesis. The parallel, fused spindles and premature cytokinesis were considered to be leading dyad formation, and tripolar spindles seemed to be causing triad formation at the tetrad stage. There was a higher frequency of parallel spindles than other spindle forms, but no significant correlations between parallel spindles and dyads were observed. However, a significant association (r = 0.68, P < 0.05) between the tripolar spindles and dyads was found. In some Microspore mother cells (MMCs), an indirect immunofluorescence examination of meiosis II revealed that the parallel spindles led to the gathering of one or two non-sister groups of chromosomes, causing an incorporation of RMSs from two daughter nuclei. Therefore, the incorporated RMSs established two nuclear cytoplasmic domains for the control of division plane, resulting in either triad or dyad formation.

Palabras clave

  • Populus euphratica
  • Unreduced pollen
  • Spindle orientation
  • Cytokinesis
  • Triploid breeding
Acceso abierto

Current plantation practices have negligible genetic effects on planted dipterocarps in the tropical rainforest

Publicado en línea: 01 Jul 2017
Páginas: 292 - 299

Resumen

Abstract

Dipterocarp trees are ecologically and commercially important in Southeast Asian tropical rainforests. For sustainable management of forest ecosystems and conservation of biodiversity, it is essential to establish plantation methods ensuring that genetic variation of the planted trees is equivalent to that in natural forests. The genetic diversity and differentiation of Shorea leprosula and Shorea parvifolia on plantations managed by a private-sector forestry company in Indonesia and those in natural populations were compared using microsatellite markers. Genetic diversity in the planted populations was as high as that in the natural populations. No clear genetic differences between each planted population and the natural forest populations were found. The genetic variation present in planted S. leprosula and S. parvifolia populations did not appear to deteriorate in the planting system implemented in Indonesia, known as Tebang Pilih Tanam Jalur (TPTJ). These results indicate that the current plantation method practiced in the region is suitable for maintaining the original genetic composition and achieving sustainable use of tropical rainforests.

Palabras clave

  • genetic diversity
  • plantation
  • Shorea
  • Southeast Asia
  • tropical rainforest
35 Artículos
Acceso abierto

Genetic characteristics reflecting the population size and disturbance regime of Siebold’s beech (Fagus crenata Blume) populations at the northernmost distribution

Publicado en línea: 01 Jul 2017
Páginas: 1 - 6

Resumen

Abstract

To understand the population dynamics of tree populations at the range limit of a species’ range, it is important to determine which population size and disturbance regime are critical to genetic diversity. Siebold's beech (Fagus crenata Blume) is a major canopy tree species of cool-temperate forests in Japan, with the northernmost distribution reaching the Kuromatsunai Depression in southwestern Hokkaido, Japan. We examined the genetic variation and dynamics of three beech forests, with different disturbance history and population attributions in the northernmost population. The Tsubamenosawa (TSU) and Sannosuke (SAN), both natural forest, have historically experienced little artificial disturbance, whereas the Soibetsu (SOI), a secondary forest, was intensively logged, and thus strongly disturbed in the past. In total, 35 alleles were detected among 12 loci, encoding 9 enzyme systems. At TSU, He and RS were 0.141 and 2.280, respectively. At SAN, He and RS were 0.142 and 2.604, respectively. At SOI were 0.182 and 2.628, respectively. Parameters of genetic diversity changed with population size, small isolated population indicated low values. Gene flow distance for low density mature trees in the natural forests was greater than that for high-density secondary forest. However, effective population sizes (Ne) were 34.7, 64.3 and 60.3 in TSU, SAN and SOI, respectively, reflecting differences in the density of mature individuals. The results suggested that the population with the low density of mature trees kept genetic diversity through long distance gene flow. The mature tree density affected the effective population size in the northernmost beech populations.

Palabras clave

  • allozyme
  • population size
  • disturbance regime
  • Fagus crenata
  • range limit
Acceso abierto

Age Trends in Genetic Parameters for Growth and Resin-Yielding Capacity in Masson Pine

Publicado en línea: 01 Jul 2017
Páginas: 7 - 17

Resumen

Abstract

Masson pine (Pinus massoniana Lamb) has long been employed as a main source of pine resin in China. To get a better understanding of genetic regulation of resinyielding capacity (RYC), a total of 50 open-pollinated families of masson pine were planted at three testing sites for progeny testing. Investigation was conducted at ages 7, 9, 11, 13, 15, 20, 24 and 26 years to study inheritance, age-age genetic correlation, and early selection efficiency for RYC, height (HT), diameter at breast height (DBH) and volume of individual tree (VOL). Growth characteristics increased gradually with age. RYC had a rapid increase at early ages (before age 15) ficients of variations (CV) for four traits showed a decreasing trend with age and the decreasing rate was rapid at early ages and minor at later ages. Heritability for four traits was relatively stable with minor fluctuation. For across-age classes, heritability was the highest for height, intermediate for RYC, and lowest for volume and DBH. RYC had highly positive genetic correlations with three growth characteristics. Genotype-by-environment interaction for four traits was stronger at Yunan than at other testing sites. Age-age genetic correlations were high for four traits studied, reaching 0.7 after age 9 for most analyses. Early selection at age 13 was highly effective for height, age 15 for DBH and volume, and age 11 for RYC.

Palabras clave

  • Pinus massoniana
  • resin-yielding capacity
  • progeny trial
  • age-age correlation
  • early selection efficiency
Acceso abierto

Mendelian segregation in eight microsatellite loci from hand- and open-pollinated progenies of Araucaria angustifolia (Bert.) O. Kuntze (Araucariaceae)

Publicado en línea: 01 Jul 2017
Páginas: 18 - 24

Resumen

Abstract

In order to use molecular markers in population genetics studies, it is important to confirm that the molecular markers used present a Mendelian segregation. The aim of this paper was to investigate the genetic segregation of eight microsatellite loci of Araucaria angustifolia (Bert.) O. Kuntze (Araucariaceae). The study was carried out comparing genetic segregation in hand- and open-pollinated progenies of maternal dioecious and monoecious trees. The Mendelian segregation was confirmed for all eight loci studied (Ag20, Ag23, Ag45, Aang01, Aang14, Aang28, As90 and CRCAc1), as no deviation from the expected segregation hypothesis was detected in the studied progenies. Therefore, these eight loci can be used for further population genetics studies of A. angustifolia.

Palabras clave

  • Brazilian pine
  • artificial pollination
  • open pollination
  • monoecy
Acceso abierto

Different diversity measures and genetic traits reveal different speciesgenetic diversity relationships: A case study in forest tree communities

Publicado en línea: 01 Jul 2017
Páginas: 25 - 37

Resumen

Abstract

Relationships between species diversity and genetic diversity, the two most important elements of biodiversity, have recently attracted considerable interest in the field of community genetics. The present study contributes to this issue by addressing three questions that seem to have been ignored so far, namely whether the use of (a) different diversity measures, of (b) different components of diversity, and of (c) different genetic traits may lead to different assessements of speciesgenetic diversity relationships. For this purpose, data on species composition and genetic traits were collected from the natural regeneration of nine forest communities, which consist of three pure and six mixed tree stands located in the Thuringian forest area. The genetic traits comprised one DNA (AFLP) and five isozyme traits all of which were determined in all species. In contrast to other studies, the species diversity was determined for two components, SD (species diversity) and NeS (effective number of genetically distinct species), and the genetic diversity was determined for three components, TSGD (the transspecific genetic diversity taken over all species of a community), ISGD and NGS (each describing a special average of intraspecific genetic diversity). Each component was quantified by measures of diversity representing four orders of the Renyi/Hillfamily. The orders correspond to the degree to which prevalence of types is considered in the diversity measure (at the lowest order, known as richness, prevalence is disregarded, with increasing order, the diversity measure reports prevalent types only). In our data, the diversity measured for each genetic trait separately showed a great range of variation across traits and components of diversity even in the same stand. The choice of the diversity component thus turned out to have a substantial effect on the assessment of the level of genetic diversity within stands. This prompted more detailed studies of the relationships between species and genetic diversity. Relationships were quantified with the help of the coefficient of co-variation, and the statistical significance of the co-variations was verified through permutation tests. The co-variations between SD and TSGD were found to be generally positive and in most cases significant, but the co-variation declined with increasing orders of diversity for most of the genetic traits. In contrast, the co-variation between SD and ISGD was not consistent for the four orders of diversity. In particular, the co-variations for the highest order were found to be negative for all traits. The results of our explorative study thus demonstrate that the assessment of levels of genetic diversity within stands as well as species-genetic interrelations critically depend on the choice of the diversity component, of the order of diversity, and of the genetic trait. These observations lend support to different and even opposing hypotheses on the processes potentially generating species-genetic relationships. Therefore, strategies in the conservation of biodiversity, for example, are suggested to be related more specifically to the components and orders of diversity to be safegarded and to consider the functions of genetic traits in relation to adaptationally relevant environmental factors.

Palabras clave

  • co-variation
  • community genetics
  • diversity components
  • genetic diversity
  • genetic traits
  • orders of diversity
  • species diversity
  • forest tree species
Acceso abierto

Genetic Variation and Correlation among Resin Yield, Growth, and Morphologic Traits of Pinus massoniana

Publicado en línea: 01 Jul 2017
Páginas: 38 - 43

Resumen

Abstract

In breeding programs, the variations and relationships among main traits need to be understood to develop selection and breeding strategies. Resin is considered as one of most important non-timber production of P. massoniana which can privides terpenes used in the chemical industry. The present study assessed the genetic variations in growth, morphologic traits, and resin yield, as well as the phenotypic and genetic correlations between these traits of 45 half-sib families of eight-year-old Pinus massoniana trees. All traits show highly significant family effects. The individual heritability for diameter at breast height (DBH) was the highest (hi2=0.55). Heritabilities for resin yield, tree height, crown depth, and the height to the live crown were slightly lower than DBH, ranging from 0.32 to 0.45. The other traits were under weak genetic control and heritabilities ranged from 0.17 to 0.20. All growth and morphologic traits were significantly correlated genetically with resin yield. Number of living branches had the highest genetic correlation with resin yield (rg=0.99), followed by DBH and number of living whorls (rg=0.73 and 0.70). Only a moderate positive genetic correlation with resin yield was found with the other traits (rg=0.47-0.57), except for height under the living branches (rg=-0.45). The results of this study indicate that both resin yield and growth can be improved simultaneously in the next generation. Of the traits assessed DBH was the optimum trait for indirectly selecting high-yielding resin trees.

Palabras clave

  • resin yield
  • growth
  • morphologic traits
  • heritability
  • genetic correlation
  • Pinus massoniana
Acceso abierto

Provenance variation in height development of Albizia falcataria under three levels of spacing in East Java, Indonesia

Publicado en línea: 01 Jul 2017
Páginas: 44 - 51

Resumen

Abstract

Nine provenances of Albizia falcataria were planted at three square spacing levels (2, 3, and 4 m) in a split-plot design at Jember in East Java, Indonesia and measured annually for six years, which is three quarters of its rotation age. The effect of spacing on mean height development became progressively evident, due to the decline in growth at closer spacing caused by intensified competition, in six provenances, i.e., three provenances each from Java and East Indonesia, which were considered better adapted to the site because of their better growth and higher survival. On the contrary, the height growth curves of two provenances from New Guinea were almost identical, irrespective of spacing, indicating a lack of plasticity to the favorable environment at wider spacing. Dominant height was defined as the average of the five tallest trees per sub-plot (350 stems/ha), the growth curves at the three spacing levels were similar in the above-mentioned six provenances and were regarded as a single curve according to AIC-values. In contrast, dominant height growth curves of the New Guinea provenances were differentiated in the order of 2, 3, and 4 m spacing, approximately proportional to the intensity of choosing dominant trees per sub-plot. These results suggest that provenance variation exists for mean and dominant height and their response to different spacing. The cause of this variation was presumably attributable to the difference in competitive ability as well as the plasticity to the given environment. The use of dominant height for growth modeling of A. falcataria was found to be the most suitable for the adapted provenances.

Palabras clave

  • Albizia falcataria
  • height growth curve
  • provenance spacing trial
Acceso abierto

Selection of Poplar Hybrid Clones (Populus ssp.) from Backcrossed Progenies of the Aigeiros Section for Industrial Purpose

Publicado en línea: 01 Jul 2017
Páginas: 52 - 60

Resumen

Abstract

As one of the fast-growing tree species, hybrid poplar (Populus ssp.) has been widely planted in Shandong Province, China. While poplar tree breeding program in the past few decades focused on the development of poplar clones with fast growth rate and disease resistance, little attention was paid to the tree traits of these clones in relation to industrial uses i.e. pulpwood as well as veneer. In this paper, growth performance of hybrid poplar clones from backcrossedprogenies obtained from cross fertilization within the Poplar Aigeiros Section was evaluated and stem traits as well as wood properties in relation to industrial use of some selected clones were assessed. Of the 40 hybrid poplar clones tested in the study, A50 and B69 were prominent in growth rate at three trial sites in Shandong Province, China.Wood properties in relation to industrial uses of the two clones were also better than or comparable to the control clone. It was concluded that A50 is more suitable for pulpwood production while B69 is suitable for a wide range of high value added application such as veneer and plywood. Further research is needed to evaluate the changes of some tree traits in relation to industrial raw materials through time.

Palabras clave

  • Populus
  • Aigeiros
  • controlled pollination
  • growth rate
  • stem traits
  • wood property
  • veneer
  • pulpwood
Acceso abierto

Crossability of Pinus sibirica and P. pumila with their hybrids

Publicado en línea: 01 Jul 2017
Páginas: 61 - 67

Resumen

Abstract

Crossability of Pinus sibirica and P. pumila hybrids and their parental species was studied using the controlled pollination method. Pinus sibirica and its hybrids were represented by grafts at the “Kedr” field station southeast of Tomsk Oblast, Russia; the parental species was of local provenance, with its hybrids obtained from the Southern Baikal region. In the case of P. pumila, trees were pollinated in a wild stand located in the Upper Angara River delta. Parental species had the highest number of filled seeds under open pollination. When they were pollinated with hybrid pollen, the trees showed nearly two-fold reductions in the number of filled seeds. Hybrids tended to abort most ovules during the first year of female cone development, resulting in a high seed abortion rate and consequent low seed production. The number of filled seeds obtained from hybrids was low, with levels ranging from 8.2 to 24.3%. Because of weak reproductive isolation between hybrids and parental species, crosses are inevitable and lead to species introgression. The hybrids probably contribute to interspecies genetic exchange both through hybrid seed production following pollination by parental species and by hybrid pollen distribution.

Palabras clave

  • hybridization
  • Pinus sibirica
  • P. pumila
  • controlled pollination
  • reproductive isolation
Acceso abierto

Computer Simulation for the Evaluation of Recombination Strategies in Intrapopulation Recurrent Selection in Eucalyptus

Publicado en línea: 01 Jul 2017
Páginas: 68 - 79

Resumen

Abstract

Intrapopulation recurrent selection (IRS) has proven to be a promising breeding method in eucalyptus, mainly through being easier to carry out when compared to reciprocal recurrent selection (RRS). However, the recombination strategies in IRS that have not yet been compared. Thus, the purpose of this study was to verify the efficiency of different recombination methods in IRS. To do so, computer simulation was used considering different heritabilities (0.1, 0.5, 1.0), different initial allelic frequencies (0.2, 0.8) and allelic interactions without dominance and with complete dominance. The initial population consisted of 1000 individuals, which were selected at random for the beginning of cycle zero. These individuals were interbred two by two. Three selection strategies were carried out and, consequently, three recombination methods: recombine the best individuals selected within the best progenies; the best individuals phenotypically selected regardless of their genealogy; or selection in the mean value of the best progenies selected. It was observed that recombination of the best individuals regardless of their genealogy and of the best individuals within the best progenies provided for gains superior to recombination having only the mean of the progenies as reference. The average degree of dominance and the heritability of the trait should be considered at the time of choosing the method of selection followed by recombination.

Palabras clave

  • Forest breeding
  • Quantitative Genetics
  • Monte Carlo
  • Breeding Strategies
  • Genetic Gain
Acceso abierto

Variability in Wild Germplasm of Natural Rubber (Hevea brasiliensis Muell. Arg.)

Publicado en línea: 01 Jul 2017
Páginas: 81 - 85

Resumen

Abstract

Para rubber (Hevea brasiliensis), a native of the Amazon forests of South America, is the chief source of natural rubber in the world. With the objective of broadening the original gene pool collected by Sir Henry Wickham in 1876, the International Rubber Research and Development Board (IRRDB) made a large collection of wild germplasm from Acre, Rondonia and Mato Grosso states of Brazil in 1981, which was distributed to various member countries including India for conservation and evaluation. In the present study, variability was assessed in a set of 195 Hevea accessions belonging to the wild gene pool in India, using 22 characterization descriptors and eight quantitative growth characters in the juvenile stage. The Shannon-Weaver diversity indices worked out for each of the 22 qualitative traits indicated a high level of diversity in the collection. The range of variation for quantitative traits viz., plant height (0.43 to 3.16 m), basal diameter (0.81 to 2.52 cm), number of whorls (1.23 to 5.48), inter-node length (4.11 to 45.26 cm), number of leaves (11.44 to 91.26), single leaf area (80.22 to 223.57 cm2), total leaf area (2356.00 to 14660.50 cm2) and leaf area index (0.24 to 1.47), also represented wide variability in the collection. The accessions were ranked for overall performance and top 10% were selected for early growth vigour. The high level of variability observed in this germplasm indicates its potential use in crop improvement programmes and for broadening the genetic base of Hevea.

Palabras clave

  • Hevea brasiliensis
  • Shannon-Weaver diversity index
  • wild rubber germplasm
Acceso abierto

Clinal variation in Pinus hartwegii populations and its application for adaptation to climate change

Publicado en línea: 01 Jul 2017
Páginas: 86 - 95

Resumen

Abstract

In order to determine the genetic variation among populations of Pinus hartwegii along altitudinal gradients, and the possible adaptive decoupling due to climatic change, a common garden test was set up with 13 provenances collected along an altitudinal transect (3150 to 3750 masl; collection sites were every 50 m of altitudinal difference) from Pico de Tancítaro, Michoacán, west-central Mexico. The test evaluated trees aged 4.5 to 5.5 years, and contemporary and future (year 2030; six model-emission scenarios) climate variables were estimated. We found significant (P<0.005) differences among populations in total elongation, final seedling height, basal diameter, rate of elongation, dry weight of needles, branches and stem, total dry weight and first principal component. We found a significant association between population performance, expressed as first principal component values, and their climate, where the best climatic predictor was the frost free period (r2=0.90, P<0.0001). This result indicates that the patterning of genetic differentiation among populations is strongly associated with a climatic and altitudinal gradient. We propose a re-delineation of fixed climatic and altitudinal seed zoning for seed and seedling movement, based on intervals of 26 days of difference of frost free period: Zone 1, from 240 to 214 days of frost free period or 12 to 11°C or 3150 to 3350 masl; Zone 2, 214 to 188 days or 11 to 10°C or 3350 to 3550 masl; and Zone 3, 188 to 162 days or 10 to 9°C or 3550 a 3750 masl. Projecting at what altitude will occur the same frost free period values by year 2030, we suggested that populations should be shifted 400 m attitudinally upward, through a program of assisted migration, aiming to realign the populations to the climate for which they are adapted. Seedling deployment should use future (year 2030) fixed seed zones, with the same projected climatic interval values than contemporary climate, although at the following altitudinal limits: Zone 12030, from 3550 to 3750 masl; Zone 22030, 3750 to 3950 masl; and Zone 32030, 3950 to 4150 masl.

Palabras clave

  • Pinus hartwegii
  • provenance
  • altitudinal genetic variation
  • seedling height
  • shoot elongation
  • dry weight
  • climatic change
  • zoning
  • assisted migration
Acceso abierto

Anatomical and Physiological Effects of Phytohormones on Adventitious Roots Development in Larix kaempferi × L. olgensis

Publicado en línea: 01 Jul 2017
Páginas: 96 - 103

Resumen

Abstract

Adventitious root development is crucial for cutting propagation in hybrid larch. In the present study, semilignified cuttings of Larix kaempferi × L. olgensis clones were used to study the morphological and anatomical changes during the different development stages and compare the changes in contents of endogenous phytohormone in two clones with evidently different rooting capacity (25-5 and 23-12), and the effects of exogenous Indole-3-Butyric Acid (IBA) on phytohormone content of a very low native rooting capacity clone (8-9) during the development of adventitious roots. The results showed that the development of adventitious root in semi-lignified cuttings involves three key stages: root cell dedifferentiation and division (14-18 DAC); meristem formation and development (25-35 DAC); root formation and elongation (50-55 DAC). The endogenous phytohormones play a key role during adventitious root development. For 25-5 and 23-12, the level of endogenous phytohormones, especially the ABA content, has an important effect on rooting capacity. For the effects of IBA on 8-9, except lower ABA content, the temporary peak of IAA on the 1 DAC was important for initiating the rooting process. The ratio of (IAA + GA3 + ZR)/ABA can be used as an indicator of rooting capacity. The anatomical and physiological data described here for semi-lignified cuttings of L. kaempferi × L. olgensis clones improves our knowledge of adventitious roots development. Our study will also benefit future research on examining the molecular mechanisms of the adventitious roots development in hybrid larch.

Palabras clave

  • anatomy
  • IBA
  • phytohormone ratio
  • adventitious roots
  • rooting capacity
  • Larix kaempferi × L. olgensis
Acceso abierto

Primer Note: A novel set of EST-SSR markers in Tamarix: a resource to characterize this genus

Publicado en línea: 01 Jul 2017
Páginas: 104 - 109

Resumen

Abstract

Both the negative and positive ecological impact of Tamarix plants is controversial, and thus a more comprehensive understanding is necessary. Tamarisks are invasive in many countries but the inter-specific transferability that characterizes simple sequence repeats (SSRs) could be harnessed to track the spread of specific genotypes or to study invasive populations. Thirteen polymorphic SSR markers, derived from expressed sequence tag (EST), were identified by first screening 26 samples of T. aphylla, T. jordanis, T. nilotica, and T. tetragyna and then 33 unidentified tamarisks from Yotvata, Israel. The mean number of alleles per locus ranged from two to 14 and the mean expected heterozygosity was 0.415. These EST-SSR markers will undoubtedly be useful in the genetic characterization of the genus Tamarix due to their high cross-species transferability which enables the estimation of the genetic diversity among and within different species, that are adapted to the same desert habitat under severe environmental constraints.

Palabras clave

  • Tamarisk
  • species identification
  • microsatellite
  • Bayesian assignment method
Acceso abierto

Genetic parameters for early growth and biomass traits of Pinus radiata D. Don under different water regimes

Publicado en línea: 01 Jul 2017
Páginas: 110 - 116

Resumen

Abstract

In Chile, genetic improvement of Radiata pine has been directed towards characters such as volume, form and wood density. Estimation of genetic parameters for growth and biomass traits in young seedlings, as a tool for early indirect selection in the P. radiata breeding program, has not been explored yet. We aimed to estimate genetic parameters for growth and biomass traits. Five-month-old P. radiata seedlings grown under wellwatered (WW) and water stress (WS) regimes were evaluated. Root collar diameter, height, shoot dry weight, root dry weight, total dry weight, height/diameter ratio and root/shoot ratio were analyzed in both treatments. Trait with the highest heritability was root/shoot ratio in WW and WS regime (h2 = 0.80 and 0.63 respectively). The highest genetic correlation was between height and shoot dry weight (rg = 0.90), under WW regime. In contrast, there were negative genetic correlations between root collar diameter and height/diameter ratio under WS regime. To breed for drought tolerance, traits such as height and root collar diameter would be effective targets for indirect selection since estimated heritabilities are high, there is sizable genetic variation, they are easily assessed, they can be measured non-destructively and they have a high genetic correlation with root/shoot ratio, a trait related to drought tolerance. The measurement of dry weights for early selection purposes is not recommended.

Palabras clave

  • heritability
  • genetic and phenotypic correlation
  • Type B correlation
  • Pinus radiata
  • water stress
  • biomass
Acceso abierto

Aspects of sexual reproduction in rare monoecious Populus nigra var. nigra trees

Publicado en línea: 01 Jul 2017
Páginas: 117 - 123

Resumen

Abstract

Individuals of the genus Populus are mostly dioecious, although deviations from strict dioecism occasionally occur. The aim of this study was to determine whether six, rare monoecious Populus nigra var. nigra trees, identified in trial plots, were fertile and capable of sexually reproducing. Controlled pollinations were carried out and compared with the results of open pollination. Viable seeds were obtained from all combinations of pollination possibilities, suggesting these monoecious trees could be used as either male or female parent and were self-fertile. However, no individuals produced by selfpollination were found among the offspring from openpollinated, monoecious trees. The parentage of some of the crosses was verified using microsatellite markers. The germination energy (GE) and germination capacity (GC) were in most cases higher for seeds produced from controlled pollinations than from open pollination. Furthermore, GE and GC were both higher when pollen from the monoecious trees was used. An association between GE and GC rates on the one hand, and the pollination method and year it took place on the other, was found in most crosses made. This study extends knowledge of the reproductive biology of P. nigra that could be utilized in conservation genetic of this endangered allogamous species.

Palabras clave

  • Black poplar
  • germination capacity
  • germination energy
  • microsatellite markers
  • monoecism
  • paternity
  • controlled pollination
Acceso abierto

Short Note: Development and characterization of 16 new polymorphic microsatellite loci for Schima superba (Theaceae)

Publicado en línea: 01 Jul 2017
Páginas: 124 - 126

Resumen

Abstract

Schima superba is a common dominant tree species in evergreen broad-leaved forest in subtropical China. Despite its multiple usages in wood industry, reforestation and traditional Chinese medicine, its genetic diversity is poorly studied. To help studying its genetic diversity and structure in the future, after microsatellite enrichment and screening, we identified 16 microsatellites in S. superba. These markers showed polymorphism in three populations. The number of alleles per locus ranged from 3 to 32 with a mean of 14. Within populations, the observed and unbiased expected heterozygosities ranged from 0.048 to 0.926 and from 0.048 to 0.949, respectively. The newly developed 16 microsatellites will be useful for investigating the genetic diversity and structure from large scale patterns to fine-scale structures in this species.

Palabras clave

  • DHS plot
  • DNA enriched libraries
  • genetic marker
  • genetic variation
  • Hardy-Weinberg equilibrium
  • linkage disequilibrium
  • marker development
  • microsatellite
  • population genetics
  • reforestation
  • spatial genetic structure
  • subtropical China
Acceso abierto

Genetic status of Norway spruce (Picea abies) breeding populations for northern Sweden

Publicado en línea: 01 Jul 2017
Páginas: 127 - 136

Resumen

Abstract

Efficient use of any breeding resources requires a good understanding of the genetic value of the founder breeding materials for predicting the gain and diversity in future generations. This study evaluates the distribution of genetic variation and level of relatedness among and within nine breeding populations of Norway spruce for Northern Sweden using nuclear microsatellite markers. A sample set of 456 individuals selected from 140 stands were genotyped with 15 SSR loci. Over all loci each individual was identified with unique multilocus genotype. High genetic diversity (average He=0.820) and low population differentiation (FST=0.0087) characterized this material. Although low in FST, the two northernmost populations were clustered as a distinct group diverged from the central populations. The population differentiation pattern corresponds well with the post glacial migration history of Norway spruce and the current gene flow and human activity in the region. The average inbreeding coefficient was 0.084 after removal loci with high frequency of null alleles. The estimated relatedness of the trees gathered in the breeding populations was very low (average kinship coefficient 0.0077) and not structured. The high genetic variation and low and not structured relatedness between individuals found in the breeding populations confirm that the Norway spruce breeding stock for northern Sweden represent valuable genetic resources for both long-term breeding and conservation programs.

Palabras clave

  • breeding stock
  • genetic diversity
  • long-term breeding
  • population subdivision
  • relatedness
Acceso abierto

Development and characterization of 28 polymorphic EST-SSR markers for Cunninghamia lanceolata (Taxodiaceae) based on transcriptome sequences

Publicado en línea: 01 Jul 2017
Páginas: 137 - 141

Resumen

Abstract

The Chinese fir (Cunninghamia lanceolata) is a very important plantation species that is mainly distributed in Southern China. However, genomic analyses of C. lanceolata have lagged significantly behind those of other conifer species due to a lack of suitable markers. To address this issue, we examined 27,666,670 reads from C. lanceolata transcriptome sequences recorded in the SRA database. Assembly produced 35,633 contigs, 1,822 (5.11%) of which contained one or more SSRs. In total, 2,156 SSRs were identified, giving an average SSR density of 68.4 SSRs/Mb. The most common SSR types were tri-SSRs (41.7%), followed by hexa-(29.8%), penta- (12.7%), di-(11.1%) and tetra-(4.7%) SSRs. EST-SSR markers based on the 1,822 SSR-containing contigs were developed using the CMiB pipeline and primer pairs were designed to target 35 loci. Polymorphism was observed in 28 of these loci, for which the number of alleles per locus ranged from 3 to 12 over 16 plus-tree individuals. The observed heterozygosity (Ho), expected heterozygosity (He) and fixation index (FIS) values for the targeted loci ranged from 0.125 to 0.938, 0.225 to 0.891 and -0.368 to 0.456, respectively. The corres - ponding PIC values ranged from 0.210 to 0.881, with an average of 0.573. Some of these markers have since been used in our ongoing genetic diversity analyses of C. lanceolata. To our knowledge, this is the first analysis of SSRs and EST-SSR markers in C. lanceolata, and the identified EST-SSR markers will be useful in future genetic analyses of C. lanceolata and related species.

Palabras clave

  • Cunninghamia lanceolata
  • expressed sequence tag
  • microsatellite markers
  • de novo assembly
  • transcriptome sequences
Acceso abierto

Wood physical properties, color, decay resistance and stiffness in Tectona grandis clones with evidence of genetic control

Publicado en línea: 01 Jul 2017
Páginas: 142 - 152

Resumen

Abstract

Tectona grandis (teak) plantations are being produced with trees from genetic improvement programs, including clonal selection. However, limited information about inheritance of wood properties is available. For studying genetic parameters of T. grandis wood properties and stem diameter two 10-yr-old trials were studied involving nominally 2 sites × 20 clones × 3 replicates × 1 ramet. Clonal variation was observed in: heartwood (HWP), pith (PP) and bark (BP) percentages; green moisture content (IMC) and density (GD); tangential (TS), radial (RS) and volumetric (VS) shrinkage and ratio tangential/radial: shrinkage (ratio T/R); L*a*b* color parameters; and stiffness and specify gravity (SG). Some wood properties evidenced strong across-sites genotypic control. The higher broad-sense heritability estimates (over 0.36) were for PP, IMC, SG, TS, VS and L*, a*, and b* color coordinates and stiffness. Low and non-significant values were estimated for HWP, BP, GD, RS, ratio T/R and decay resistance of sapwood and heartwood to Trametes versicolor and Pycnoporus sanguineus. However, HWP showed marked clone x site interaction. Phenotypic and tentatively estimated genotypic correlations indicate that selecting faster-growing clones will improve some important wood properties, such as increasing HWP, and decreasing PP and BP, without affecting other wood properties. Selecting clones for denser wood, as expected, improved stiffness, should decrease IMC and affect negatively b* (yellow/blue) color. Clone selection with lower L* values could increase redness (a*) of wood.

Palabras clave

  • teak
  • genetic parameters
  • broad-sense heritability
  • genotypic correlations
  • wood properties
  • heartwood color
  • wood decay
Acceso abierto

Growth and breeding of aspen in Russia

Publicado en línea: 01 Jul 2017
Páginas: 153 - 160

Resumen

Abstract

Researches results are presented that describe variation in natural aspen stands and hybrid collections in Central European Russia. The subject of the study was the selection of the most productive and resistant to heart rot caused by fungus Phellinus tremulae (Fomes

igniarius) stands. Mechanical wood properties, fodder values and other valuable characteristics of aspen are also shown. The valuable stands and hybrids which require conservation were selected for breeding and practical use.

Palabras clave

  • aspen
  • heart rot resistant
  • breeding
  • hybrids
  • forms
  • mechanical properties
  • fodder value
Acceso abierto

Characterization of genes expressed in Casuarina equisetifolia in response to elicitation by cell wall components of Trichosporium vesiculosum

Publicado en línea: 01 Jul 2017
Páginas: 161 - 172

Resumen

Abstract

Casuarina equisetifolia has the widest distribution of all Casuarina species and is a nitrogen-fixing tree planted in tropical/subtropical littoral zones of Asia, the Pacific and Africa for coastal reclamation, charcoal making, pulp and timber. Trichosporium vesiculosum, the causal agent of blister bark disease, is a serious pathogen of C. equisetifolia. The present study was undertaken to understand the molecular mechanisms involved during pathogen cell wall elicitation in this hardy tree species. Transcript profiling during elicitation induced by cell wall components of T. vesiculosum revealed expression of resistance genes; cytochrome oxidase; trans membrane proteins; genes involved in programmed cell death like 26S proteasome and ubiquitin activating enzyme; early nodulin gene, wound inducible metallocarboxy peptidase inhibitor, glucanase, metal binding protein and signal recognition particle. The fold expression of selected transcripts including glucanase, 26 S proteasome, signal recognition particle, cytochrome oxidase and the metal binding protein using RT-qPCR revealed 12-59 fold increase in expression after 48 hours of elicitor treatment. The expression of these transcripts during abiotic stresses like heat, mechanical wounding, salt (NaCl) and drought (PEG) was also analyzed. Glucanase was up-regulated significantly during wounding and heat stress while proteasome was up-regulated 1-4 fold during NaCl, PEG and wounding stress. The novel transcript CeHMA was up-regulated under all the stress conditions. This is the first report on molecular defense in C. equisetifolia and has provided a pool of candidate genes for detailed molecular dissection to further broaden the knowledge on the response of woody perennials during pathogen cell wall elicitation.

Palabras clave

  • Abiotic stress
  • elicitor treatment
  • transcript profiling
  • tree defense
Acceso abierto

Genetic analysis and clonal stability of two yellow cypress clonal populations in British Columbia

Publicado en línea: 01 Jul 2017
Páginas: 173 - 186

Resumen

Abstract

Genetic analysis of height and form at age 12 years of 697 yellow cypress (Callitropsis nootkatensis [D. Don] Oerst.) clones tested across seven sites in coastal British Columbia (BC) were explored in populations: Population 1 - No Pedigree and Population 2 - Reconstructed Pedigree. Genetic variances were statistically significant but generally higher σ̂g2 was observed for Population 2. Height and form were under low to moderate genetic control as indicated by clonal repeatability and estimates were relatively similar between populations. For example, average Ĥ2 in Population 2 was 0.31 for height (range: 0.18-0.45) and 0.22 for form (range: 0.06-0.32). While average Ĥ2 in Population 1 was 0.25 for height (range: 0.19-0.35) and 0.18 for form (range: 0.09-0.27). The reconstructed pedigree in Population 2 allowed partitioning the genetic variance (σ̂g2) into component parts of additive (σ̂a2), specific combining ability (σ̂s2 ), and clone (σ̂c2 ); however, general lack of structure within the population resulted in variance components to be estimated with little precision for additive and specific combining ability. The majority of genetic variation was associated with clone for both traits. For example, σ̂c2 accounted for 57.6% and 62.5% of the total genetic variance for height and form, respectively. Growth and form responses of clones across test environments were relatively stable and overall type-B genetic correlations were in excess of 0.8 for both traits implying clones selected for production populations should respond favorably across the seed planning zone for yellow cypress in coastal BC.

Palabras clave

  • Yellow cypress
  • clones
  • genetic testing
  • genotype x environment
  • clonal repeatability
Acceso abierto

Analyses of Genotypic Variation in White Poplar Clones at Four Sites in China

Publicado en línea: 01 Jul 2017
Páginas: 187 - 195

Resumen

Abstract

Growth characteristics have a complex inheritance pattern, and the gene-environment interaction makes predicting tree responses to environmental change difficult. The primary goals of this study are to evaluate the variation in growth traits of different white poplar clones and to measure the inter-site variation and ecological sensitivities. In the experiment, a total of 30 white poplar clones were planted and measured over 5 years for height (H) and diameter at breast height (DBH) at four different sites in North China. ANOVA results showed that there were significant differences in H and DBH between clones at each site (P<0.01). Phenotypic and genotypic variation, and the repeatability of H and DBH, increased with the tree growth, which suggested that the inter-clone variation became gradually larger under the control of genetic factors. Under a selection ratio of 20%, the genetic gains of H and DBH also increased with the tree growth at the same site. Correlation analysis showed a significantly positive association between H and DBH both at the same age and sites, but the correlation coefficients decreased with increasing age. In conclusion, genetic gains were not equal between different sites, indicating differences in the influence of environment on the poplar genotype. Further investigations may be able to determine the role of environment for tree breeding programs and genetic selection.

Palabras clave

  • poplar
  • variation
  • repeatability
  • genetic gain
Acceso abierto

Growth differences and genetic parameter estimates of 15 teak (Tectona grandis L.f.) genotypes of various ages clonally propagated by microcuttings and planted under humid tropical conditions

Publicado en línea: 01 Jul 2017
Páginas: 196 - 206

Resumen

Abstract

Fifteen clones of teak (Tectona grandis) produced by micropropagation from 0.5 to more than 60 yr-old selected ortets were established in a clonal test in Sabah (East Malaysia) under 2500 mm of annual rainfall to compare their growth performances during the first 7 years of development. Field establishment was good with average mortality less than 10%. The clones developed rapidly true-to-type with significant between-clone differences in growth. Ranges of clone means were 13.6 to 19.3 m in height, 16.3 to 23.4 cm in diameter at breast height (DBH) and 129 to 264 dm3 in volume. Broad sense heritability estimates for these growth traits were lower overall for single trees (H2i) than for clone means (H2c) (H2i ≤ 0.257 vs H2c ≤ 0.634 for height, H2i ≤ 0.120 vs H2c ≤ 0.383 for DBH and H2i ≤ 0.125 vs H2c ≤ 0.364 for volume). The highest genetic gain that could be expected from the best three clones out of the fifteen compared was at age 2 for height (+0.66 m, or +11.7%), and age 3 for DBH (+0.87cm, or +10.4%) and volume (+4.65 dm3, or +15.7%). Age-related phenotypic correlation values were reliably (P < 0.0001) higher and more consistent for DBH (rP ≥ 0.61) than for height (0.37 ≤ rP ≤ 0.69), or than between DBH and height, except for height at 3 (0.51 ≤ rP ≤ 0.63) and 6 (0.55 ≤ rP ≤ 0.69) years. Height and DBH were moderately to highly genetically correlated (0.54 ≤ rG ≤ 0.90).

Palabras clave

  • broad sense heritability
  • clone
  • genetic correlations
  • genetic gain
  • growth
  • maturation
  • rejuvenation
  • vegetative propagation
Acceso abierto

Isolation and characterization of chloroplast microsatellite markers in the invasive tree species Robinia pseudoacacia L.

Publicado en línea: 01 Jul 2017
Páginas: 207 - 209

Resumen

Abstract

Robinia pseudoacacia is one of the most problematic invasive alien species in Japan. Information on genetic diversity and population structure is urgently required in order to generate effective management strategies. To assist such efforts we have identified five chloroplast microsatellite (cpSSR) markers for R. pseudoacacia by amplifying noncording regions of chloroplast DNA (cpDNA) using universal chloroplast primers. Among 857 individuals these cpSSR markers showed substantial polymorphism, with three to eight alleles per locus and gene diversity ranging from 0.387 to 0.713. These cpSSR makers will be useful for analyzing maternal lineages and population genetic structure of R. pseudo - acacia.

Palabras clave

  • cpSSR
  • Maternal lineage
  • Black locust
Acceso abierto

Induction of Quercus ilex L. haploid and doubled-haploid embryos from anther cultures by temperature-stress

Publicado en línea: 01 Jul 2017
Páginas: 210 - 217

Resumen

Abstract

This paper describes a method to obtain haploid and doubled-haploid (DH) embryos using anther cultures of holm oak (Quercus ilex L.). The production of haploids and DH through gametic embryogenesis provides an attractive biotechnological tool for developing homozygous lines from heterozygous parents, which is important in breeding programs, as well as in genetic studies. As a consequence, protocols to produce homozygous plants have a significant impact on forest tree improvement. Anthers were subjected to different temperature treatments for embryo induction: a cold pre-treatment (4°C) from 3 to 7 days was carried out at the beginning, followed by a heat shock (33°C) from 2 to 5 days. Most anthers responding to these stress treatments contained vacuolated microspores, indicating that this developmental stage is responsive to embryogenesis induction in holm-oak microspores. In all cases, embryos grew from the interior of the anthers, breaking through the degenerating anther walls. Under these conditions, embryo formation occurred in 31 anthers between 46 and 95 days after culture initiation. Embryo analysis performed with flow-cytometry and DNA-microsatellite markers showed haploid profiles and/or spontaneous doubling of the chromosomes during early regeneration stages. This is, to our knowledge, the first published report on gametic embryogenesis in holm oak.

Palabras clave

  • anthers
  • holm oak
  • microsatellite DNA-markers
  • pollen embryogenesis
  • Quercus ilex
Acceso abierto

Genetic variation and genetic gain in growth traits, stem-branch characteristics and wood properties and their relationships to Eucalyptus urophylla clones

Publicado en línea: 01 Jul 2017
Páginas: 218 - 231

Resumen

Abstract

Growth traits, wood properties, stem-branch characteristics and bark percentage were assessed for 60 Eucalyptus urophylla S.T. Blake clones in southern China measured at age 21, 52, 71 and 96 months. Analysis of variance showed that there were significant differences on growth traits, wood properties and individual tree wood weight among clones. Coefficients of genotypic variation ranged from 12.12% to 53.16% for growth traits, 9.02% to 20.18% for wood properties, 21.75% to 22.71% for stem-branch characteristics, 28.31% for bark percentage and 51.20% for individual tree wood weight. Repeatability ranged from 0.36 to 0.53 for growth traits, 0.35 to 0.51 for wood properties, 0.21 to 0.24 for stembranch characteristics, 0.07 for bark percentage and 0.31 for individual tree wood weight. The strongly negative genotypic correlations suggesting that selection on growth traits at 21 months can not be effective to predict growth traits at 96 months whereas it could be used to predict growth traits at 52 and 71 months. The genotypic correlations between growth traits and basic density were ranged from -0.78 to 0.28 and weakly positive phenotypic correlations were found between growth traits and basic density, ranging from 0.03 to 0.09. The selection gain on diameter at breast height over bark by different selection proportions at 21, 52, 71 and 96 months old expressed that selection gain at 71 months was some what higher than that at other ages during 10% to 30% selection proportion, while selection gain at 52 months was some what higher than that at other ages during 60% to 90% selection proportion. Wood properties and individual tree wood weight which are strongly related to end production and economically important in pulp production should be studied extensively especially for pulp breeding.

Palabras clave

  • multiple traits
  • nondestructive evaluation
  • individual tree wood weight
  • repeatability
  • age trend
  • simple weighting coefficient method
Acceso abierto

Using portfolio theory to improve yield and reduce risk in black spruce family reforestation

Publicado en línea: 01 Jul 2017
Páginas: 232 - 238

Resumen

Abstract

Family forestry, defined as the deployment of families in mixture into plantations, is becoming an attractive option for black spruce (Picea mariana (Mill.) BSP) in New Brunswick, Canada. With many elite families of black spruce being available, there is a knowledge gap regarding how to compose a mixture of families that optimally balances the objectives of increased yield and reduced risk. This study, based on real field test data, investigates the application of a model based on the modern portfolio theory to optimally balance yield and risk when selecting a portfolio (mixture) of black spruce families to deploy in reforestation. The risk was expressed as the variance of the family portfolio, an effective indicator of yield stability. This is an innovative approach in forestry and it is compared to the currently used method, truncation-deployment, defined as the equal deployment of seed of selected families. Results show that the portfolio theory searched for the combination of yield and stability and produced family portfolios maximizing yield at a given stability or minimizing yield instability at a given yield. The portfolio theory was never inferior in maximizing yield to the truncation- deployment approach when yield stability is a concern. We recommend using portfolio theory to determine family portfolios for family forestry. While this study targets to family forestry, the results may be relevant to other deployment strategies where stability is a concern, such as clonal forestry.

Palabras clave

  • family forestry
  • portfolio theory
  • yield stability
  • tree improvement
  • black spruce
Acceso abierto

Identification of upregulated genes in laminarin-treated poplar (Populus alba × P. tremula var. glandulosa) suspension cells by suppression subtractive hybridization and cDNA microarray

Publicado en línea: 01 Jul 2017
Páginas: 239 - 245

Resumen

Abstract

Elicitors trigger defence responses in plant cells through signal transduction pathways, leading to accumulation of pathogenesis-related (PR) proteins and, eventually, pathogen resistance. To understand defence responses of hybrid poplar (Populus alba × P. tremula var. glandulosa), we isolated and characterized upregulated genes in poplar cells by laminarin-induced elicitation using suppression subtractive hybridization (SSH) and cDNA microarray approaches. A total of 1,269 clones in the SSH library were sequenced and a cDNA microarray, containing 265 unique subtracted clones, was fabricated. From the microarray results, 37 clones were found to be upregulated by laminarin treatment and their putative functions are discussed. Genes involved in signal transduction, transcriptional regulation, and phytohormone biosynthesis were upregulated. Other genes encoding PR proteins, peptidases, and an ABC transporter, as well as genes involved in lignification and protein synthesis and turnover, were also identified. Our results suggest that well-organized defence responses, from signal transduction to accumulation of PR proteins, are activated in poplar cells by laminarininduced elicitation and could contribute to resistance against pathogens.

Palabras clave

  • Elicitor
  • Gene expression
  • Laminarin
  • Microarray
  • Poplar
Acceso abierto

Microsatellite markers for Eucalyptus pilularis (Subgenus Eucalyptus); sourcing genetic markers outside the subgenus

Publicado en línea: 01 Jul 2017
Páginas: 246 - 255

Resumen

Abstract

Microsatellite markers remain the most broadly used molecular marker in eucalypt genetics. A major advantage of microsatellite markers is that they often transfer readily between related taxa circumventing the need to develop new markers de novo in each species. Markers have been developed for a number of species of major economic importance, mainly from the Subgenus Symphyomyrtus, but these may also be available for use in species of lesser economic importance from other subgenera. Here we report on the sourcing of microsatellite markers for E. pilularis (Subgenus Eucalyptus (Formerly Monocalyptus)) from species outside the subgenus. Ninety-seven precent (60 out of 62) of loci that amplified in the source taxon (E. grandis) also amplified in the target taxon E. pilularis. By characterising them on a diversity panel (n=24) and a pedigree, a subset of 41 loci were distilled out that could be scored reliably and were polymorphic (Mean unbiased heterozygosity= 0.81). Predictions of efficient microsatellite marker transfer among eucalypts based on low evolutionary divergence have largely been borne out and are congruent with accumulating evidence of low sequence divergence within Eucalyptus. Upon this favourable background for microsatellite marker transfer, this study indicates highly efficient transfer is possible by identifying loci with broad PCR optima and adoption of approaches that favour cross-species transfer.

Palabras clave

  • Monocalyptus
  • Eucalyptus
  • Symphyomyrtus
  • genetic diversity
  • microsatellite marker
  • internal transcribed spacer
  • ITS CCR
Acceso abierto

Variation in seed traits and oil content in 24 Jatropha curcas L. seed sources from Asia, Africa and Papua New Guinea

Publicado en línea: 01 Jul 2017
Páginas: 257 - 264

Resumen

Abstract

This study was carried out to determine the extent of variation in seed traits and oil content among 24 seeds sources of Jatropha curcas from 8 countries in Asia, Africa and Papua New Guinea. There were marked differences in the length (range 15.88-19 mm), breadth (10.20-11.71 mm), thickness (7.95-9.37 mm) and volume index of seed (1337-2000 mm3), weight of seed (42.67-80.20 g) and kernel (18.44-51.04 g), kernel/seed ratio (0.43-0.66), and oil content in seed (18.08-37.89%) and kernel (34.02-59.09%). In general, seeds from Laos, Mali, Papua New Guinea, Philippines and Thailand were larger and heavier than sources from China and India, but contained lower oil content in seed and kernel. Principal component analysis revealed that seed and kernel weight and oil content in whole seed and in kernel were useful characteristics in explaining the variation pattern among seed sources. Seven out of the 24 seed sources investigated in this study are considered promising for planting for oil-seed production. This study underpins the importance of selecting suitable seed sources for commercial plantation establishment of J. curcas.

Palabras clave

  • Jatropha curcas L.
  • biofuel
  • seed size parameters
  • seed oil content
  • principal component analysis
Acceso abierto

Genetic Variation in Wood Property and Growth of Taiwania (Taiwania cryptomerioides Hayata)

Publicado en línea: 01 Jul 2017
Páginas: 265 - 276

Resumen

Abstract

The genetic variation in wood property and growth of Taiwania (Taiwania cryptomerioides) was investigated at two test sites in the same general location, but one at 1200 m (LK20) and another at 1900 m (LK24). A rangewide sample of 48 open-pollinated families in Taiwan was involved. The test plantations were 16 years old when the wood property data were collected. Traits studied include wood specific gravity, tracheid length, ring width. DBH at ages13, 16, and 22 and height at age 13 were also analyzed. Site environment had a dominant effect on growth and wood density, but showed little interaction with family. The site effect was evident in large between-site differences in means, range of family means, and size of family variance components and heritability estimates. These differences are attributable to the site characteristics of LK24 (high elevation, upper slope near a mountain crest) and an unfavourable local climate. Taiwania is fast growing and produces quality wood, and is also an interesting species from the perspective of evolutionary biology. Protection of its genetic variability should be a priority to be managed. We propose that the existing five progeny tests be protected since these tests well-represent the genetic variability of the species in Taiwan.

Palabras clave

  • Taiwania cryptomerioides
  • genetic variation
  • site effect
  • Taiwan
Acceso abierto

Genetic parameters and efficiency of early selection for half rotation-aged growth and form traits in Pinus taeda in China

Publicado en línea: 01 Jul 2017
Páginas: 277 - 284

Resumen

Abstract

Genetic parameters for height (H), diameter at breast height (DBH), stem straightness (STR), and under crown clear bole height (CH) of loblolly pine (Pinus taeda L.) were estimated for 255 families (209 open pollinated (OP) and 46 controlled pollinated (CP) families) using a family model and an individual tree model at age 1, 2, 3, 5, 11, and 15 years. Heritability estimates for growth traits of individual trees at age 11 years were the highest (0.17-0.78), and those at age 15 years were the lowest (0.05-0.74). Heritability estimates for DBH, STR, and CH were lower than those for H. Genetic correlations between H and DBH were generally strongly positive, attained a maximum values at age 2 to 3, and declined slightly thereafter. The genetic correlations between CH at age 11 and both H and DBH at different ages were moderate. Age-age genetic correlations for growth traits were moderate to high (0.56-0.91) at age 5 for half-rotation age (15 years), indicating the opportunity exists for early selection. Indirect selection from the age 5 to 11 years for H and DBH could be expected to produce gains of over 50% and 35% respectively, for these two ages, relative to direct selection at age 15. Efficiencies of early selection for H and DBH indicated that growth at maturity could be improved by early selection.

Palabras clave

  • age-age correlation
  • genetic correlation
  • genetic gain
  • height
  • heritability
  • Pinus taeda
Acceso abierto

Occurrence and cytological mechanism of numerically unreduced pollen in diploid Populus euphratica

Publicado en línea: 01 Jul 2017
Páginas: 285 - 291

Resumen

Abstract

Unreduced gametes are the driving force for the polyploidizaiton of plants in nature, and are also an important tool for breeding of triploid individuals. The final heterozygosity of a 2n pollen grain depends on the cytological mechanism behind 2n pollen formation. In this study, meiotic abnormalities were analysed using fluorescent chromosome staining and indirect immunofluorescence during the microsporogenesis of 18 genotypes of diploid P. euphratica Oliv. (2n = 2x = 38). Among the 18 genotypes, 16 genotypes produce 2n pollen and two genotypes produce only normal n pollen. In all 2n pollen producers, we found that the first meiotic division was normal but that the second division was characterized by frequent abnormal spindle orientation (parallel, tripolar, and fused spindles) and premature cytokinesis. The parallel, fused spindles and premature cytokinesis were considered to be leading dyad formation, and tripolar spindles seemed to be causing triad formation at the tetrad stage. There was a higher frequency of parallel spindles than other spindle forms, but no significant correlations between parallel spindles and dyads were observed. However, a significant association (r = 0.68, P < 0.05) between the tripolar spindles and dyads was found. In some Microspore mother cells (MMCs), an indirect immunofluorescence examination of meiosis II revealed that the parallel spindles led to the gathering of one or two non-sister groups of chromosomes, causing an incorporation of RMSs from two daughter nuclei. Therefore, the incorporated RMSs established two nuclear cytoplasmic domains for the control of division plane, resulting in either triad or dyad formation.

Palabras clave

  • Populus euphratica
  • Unreduced pollen
  • Spindle orientation
  • Cytokinesis
  • Triploid breeding
Acceso abierto

Current plantation practices have negligible genetic effects on planted dipterocarps in the tropical rainforest

Publicado en línea: 01 Jul 2017
Páginas: 292 - 299

Resumen

Abstract

Dipterocarp trees are ecologically and commercially important in Southeast Asian tropical rainforests. For sustainable management of forest ecosystems and conservation of biodiversity, it is essential to establish plantation methods ensuring that genetic variation of the planted trees is equivalent to that in natural forests. The genetic diversity and differentiation of Shorea leprosula and Shorea parvifolia on plantations managed by a private-sector forestry company in Indonesia and those in natural populations were compared using microsatellite markers. Genetic diversity in the planted populations was as high as that in the natural populations. No clear genetic differences between each planted population and the natural forest populations were found. The genetic variation present in planted S. leprosula and S. parvifolia populations did not appear to deteriorate in the planting system implemented in Indonesia, known as Tebang Pilih Tanam Jalur (TPTJ). These results indicate that the current plantation method practiced in the region is suitable for maintaining the original genetic composition and achieving sustainable use of tropical rainforests.

Palabras clave

  • genetic diversity
  • plantation
  • Shorea
  • Southeast Asia
  • tropical rainforest

Planifique su conferencia remota con Sciendo