Volume 65 (2016): Edition 1 (December 2016)

Eucalyptus camaldulensis has potential for timber, energy, pulp and cellulose production in Brazil due to its ability to adapt to a variety of environmental conditions. The use of improved seeds, selected for economic growth traits, is necessary to increase productivity of commercial stands. Seed seedlings orchards (SSO) are one option for improved seed production. However, pollen contamination from unimproved populations, as well as non-random mating in the SSO, can decrease the predicted genetic gains in selected populations. Thus, we investigate the mating system, pollen flow and dispersal patterns in an E. camaldulensis SSO and progeny test (PT), established with seedlings collected in the SSO, using seven microsatellite loci. All trees in the SSO were mapped, sampled, and genotyped. For the PT, we sampled, genotyped, and measured the total height of seedlings from 25 families. We detected 10 % inbreeding in the PT, resulting mainly from selfing. Furthermore, we found a correlated mating rate of 18.5 % in the SSO, indicating that within the PT there are some full-sibs. Using paternity analysis, we found 14.7 % pollen contamination and a pattern of pollen dispersal between near neighbor trees in the SSO. We found 9.5 % of inbreeding depression for seedlings height. Due to pollen contamination and nonrandom mating in the SSO, the actual genetic gains for growth traits in the PT are probably lower than the predicted genetic gains. We discuss some management strategies in the SSO that can be used to increase genetic gains in commercial reforestation established using seeds collected from the SSO

Black poplar (Populus nigra L.) is a keystone species of riparian softwood forests along riversides in vast areas of Europe, Western Asia and Northern Africa. Since the end of the 20^th century, black poplar has been recognized as an endangered species throughout Europe due to the loss of its natural habitat and possible crossbreeding with hybrid poplars. Using twelve nuclear SSR loci, we analysed the genetic structure of four native populations from three river valleys in the northern part of Serbia. All tested loci were highly polymorphic, displaying 8 to 25 alleles per locus, overall 179 detected alleles and an average effective number of alleles 5.87. Observed heterozygosity (overall Ho = 0.703) has been lower than the expected (overall H_e = 0.808) in each population, which indicates positive mean of fixation index values (overall F_is > 0 (0.132)). An AMOVA analysis revealed that the highest degree of genetic variation occurred within populations (95.33 %) while the genetic variation between populations was really low (4.67 %). High gene flow and no significant loss of allelic diversity have been recorded in the studied populations in Serbia.

Growth characteristics and fertility variations were evaluated at four natural stands of tropical arid zone species, A. leucophloea in southern India. Three stands (TNL 1, TNL 2 and PDM) were situated in dry upland regions while one stand (RKP) was at waterlogged site. The tree height and girth at breast height did not vary between stands in two years. Fertility variation (sibling coefficient, ψ) was estimated based on flowering abundance and fruit set collected for two consecutive years. Fruit production per tree was generally lower in the RKP stand than the other three stands. No year-to-year variation was observed on fruit set in all stands. Growth and flower production showed a weak-positive correlation in both years (R² = 0.39 to 0.1). The correlation to check if the larger inflorescence size, the higher number of fruit production was also failed. Male fertility variation did not vary much among stands (ψ_m = 1.28 ~ 1.62). Female fertility variation was low (ψ_f = 1.71 ~ 2.02) in the three stands situated in dry upland regions than the RKP stand (ψ_f = 4.09 ~ 4.16). The cumulative contribution of trees to the overall fertility was deviated from the ideal situation (equal contribution) in all stands, especially the RKP stand showed a skewed distribution (R² ≤ 6.5). The effective population size was low in the RKP predicting a high genetic drift when compared with other sites. Similarly high group coancestry and low gene diversity were observed in the stand RKP. The implications of fertility variation on gene diversity of the species and future management of the natural stands were also discussed.

The purpose of this work was to estimate genetic parameters and selection gain of Pinus caribaea var. hondurensis progeny trial for wood and resin production as well as correlation between them. Experiment was established in complete lattice square 10 × 10 (triple), 100 treatments, 10 plants per plot, 3 m × 3 m spacing. Twelve years after planting the trial had thinned considerably leaving six plants per plot. Twenty-seven years after planting height, diameter at breast height (dbh) and resin production were measured. Deviance analysis, genetic parameter estimates, selection expected gain, genetic and phenotypic correlation were based on REML/BLUP method. Significant phenotypic differences were observed among and within families for all traits. The thinning at 12 years after planting, contributed positively to dbh increase and resin production, with an average of 30.60 cm and 4.83 kg tree⁻¹year⁻¹. The individual narrow sense heritability ranged from 0.25 to 0.38 for dbh and volume. Genetic and phenotypic correlation between growth traits were positive, and significant. Therefore, different selection strategies will be proposed separately for both traits (resin and wood). The selection gains were significant, especially with 10 % selection intensity (individual selection) for dbh (7.53 %) and resin (13.49 %). The trial has had good performance for growth, resin and genetic variability to support the next breeding generation

Complementary progeny tests allow for simultaneously ranking parents for their general combining ability (GCA) and within-family forward selection. To do this, progeny tests are established with different types of genetic entries (i.e., half-sib and full-sib seedlings, respectively), and different experimental designs. This study proposes a combined analysis of the GCA and full-sib (FS) tests using the mixed model approach to predict simultaneously the breeding values of grandparents, parents, full-sib families and offspring on the same scale. Moreover, a first order autoregressive spatial mixed model for the GCA tests was also implemented in the combined analysis. Our empirical study in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) shows that additional information provided from relatives and the overlap genetic entry among GCA and FS tests via the proposed combined analysis, improves the accuracies of breeding values compared to the non-combined analysis. The improvements in the accuracies of breeding values for backward and forward selections were generally modest. Spatial and combined analyses gave slightly better results than the non-spatial combined model.

Understanding the genetic diversity of Acacia melanoxylon is very important in species selection and improvement. The present study aimed to identify microsatellite markers and determine the genetic diversity of 45 preferred clones selected from 9 Chinese districts. Seventy-six simple sequence repeat (SSR) markers developed for other Acacia species were screened. Seventeen SSR markers showed polymorphic patterns and amplified 134 alleles. Polymorphism information content (PIC) values ranged from 0.044 to 0.911. The average allele number per locus ranged between 2 and 18, averaging 8.06. Nine SSR markers were highly informative, with PIC values above 0.60. These findings demonstrated that SSR markers could be used to differentiate A. melanoxylon genotypes. Cluster analysis using UPGMA separated the 45 clones into 3 distinct groups at a similarity coefficient of 0.72. The clone groups identified in this study would be useful in developing intraspecific hybrids to exploit hybrid vigor as well as for commercial cultivation and genetic base broadening. The DNA fingerprints obtained for each clone could be used for biodiversity conservation.

Wisteria floribunda is a deciduous liana species widely distributed in Japan. It is essential to evaluate the clonal structure of this species because high clonal ability enables lianas to make dense colonies after canopy gaps occur. Therefore, we developed 10 microsatellite markers for W. floribunda from genomic shotgun sequences available in the publicly available database to study clonal structure and life history strategy of this species. The number of alleles per locus ranged from 7 to 16, with an average of 10.2. The observed and expected heterozygosity ranged from 0.483 to 0.926 and from 0.642 to 0.916, with averages of 0.769 and 0.800, respectively. These findings will contribute to the understanding of ecological roles and management of this species.

Taxus yunnanensis, which is an endangered tree that is considered valuable because it contains the effective natural anticancer metabolite taxol and heteropolysaccharides, has long suffered from severe habitat fragmentation. In this study, the levels of genetic diversity in two populations of 136 individuals were analyzed based on eleven polymorphic microsatellite loci. Our results suggested that these two populations were characterized by low genetic diversity (N_E = 2.303/2.557; H_O = 0.168/0.142; H_E = 0.453/0.517), a population bottleneck, a low effective population size (Ne = 7/9), a high level of inbreeding (F_IS = 0.596/0.702), and a weak, but significant spatial genetic structure (Sp = 0.001, b = −0.001*). Habitat fragmentation, seed shadow overlap and limited seed and pollen dispersal and potential selfing may have contributed to the observed gene tic structure. The results of the present study will enable development of practical conservation measures to effectively conserve the valuable genetic resources of this endangered plant.

Taxus is an important genus which is well-known for Taxol. Its genetic analyses were lagged behind those of other conifers due to lack of suitable molecular markers. In this paper, we explored polymorphic loci for Taxus mairei and tested their transferability across species based on 150 EST-SSR loci already developed for Taxus cuspidata previously. The results showed that 103 loci were polymorphic, the number of alleles per locus ranged from 2 to 11 over 16 individuals. The observed heterozygosity (H_o) and expected heterozygosity (H_e) varied from 0 to 1 and 0.0625 to 0.891, respectively. The PIC values ranged from 0.11 to 0.754 with an average of 0.453. The average cross-species transferability was 96.07% among 5 species. Most of these loci can be used as universal markers in Taxus genus. The PCA results showed these markers have strong power to identify different species. These markers will be useful for further studies on genetic analysis and conversation of Taxus mairei.

The study was conducted to estimate the stability, adaptability, productivity and genetic parameters in Slash pine second-generation half-sib families, considering phenotypic traits in early age. Forty-four families from a first generation seed orchard in Colombo-PR, Brazil, were used in this study. Two progenies tests were established in a randomized complete block design. The first test was implemented in March 2009 in Ribeirão Branco, São Paulo state, containing 40 blocks, one tree per plot, 44 treatments (progenies) and 6 controls. Another test was implemented in Ponta Grossa, Paraná state, using the same experimental design and number of plants per plot, and with 24 treatments, 32 blocks. The growth traits evaluated were total height, diameter at breast height (dbh) and wood volume, within five years. The form traits evaluated were stem form, branch thickness, branch angle, number of branches, fork and fox tail five years after planting. Deviance analysis and estimates of stability, adaptability, productivity and genetic parameters were performed using the methods of best linear unbiased predictor (BLUP) and residual maximum likelihood (REML). There was significant variation among progenies for growth and form traits. Considerable genetic variation was detected mainly for wood volume. High coefficients of genetic variation and heritability showed low environmental influence on phenotypic variation, which is important for the prediction of genetic gain by selection. Crosses between different progenies individuals groups will be prioritized for obtaining heterotics genotypes and increase the probability of obtaining high specific combining ability.