Volumen 24 (2016): Edición 1 (June 2016)

Two Tomato spotted wilt virus (TSWV) isolates H1 and H2 found in Hippeastrum hybridum plants were characterized based on biological, serological, and molecular properties. Virus isolates showed differences in symptom expression – H1 isolate displayed severe necrotic spots and patterns, whereas mild mosaic symptoms were observed on H2-infected H. hybridum plants. Both TSWV isolates showed comparable reactivity with TSWV-specific antibodies and they induced similar symptoms on herbaceous indicator plants, but some differences between these isolates were detected at the nucleotide sequence level of genomic S and M ssRNAs segment fragments. The nucleotide sequences encoding nucleocapsid (N) and nonstructural (NSs and NSm) proteins showed 98.2%, 97.5%, and 96.5% identity, respectively. Phylogenetic analysis of N and NSs sequences conducted for tested isolates and 31 TSWV isolates included for comparison revealed that H1 and H2 isolates fell into the same cluster and they were grouped together with isolates found previously in different vegetables, ornamentals, and weeds. When NSm ORF was analyzed, the tested isolates formed a separate cluster: H1 isolate showed the highest affinity with TSWV isolates infecting chrysanthemum and pepper plants, whereas H2 isolate was most closely related to other virus isolates found in sweet pepper and tomatoes. These results indicate that both isolates were reassortants between different virus isolates, and represented two novel genetic patterns of TSWV.

Quality of cut flowers is an important issue at postharvest as well as an important factor contributing to marketing of and profitability from the tuberose. In this study, the effects of citric acid (CA) and hydrogen peroxide (H₂O₂) added to the vase water on postharvest quality of tuberose cut flowers were investigated. CA was applied in concentrations of 50, 100, 200, 400 mg·dm⁻³ and H₂O₂ in concentrations of 10, 20, 40 and 80 mg·dm⁻³ and distilled water as control treatment. Results showed that both compounds had significant positive effects on solution uptake, wilting and abscission of florets, relative water content, chlorophyll content, and vase life duration. The effects of 100 and 200 mg·dm⁻³ of CA and 20 and 40 mg·dm⁻³ of H₂O₂ proved to be more effective than other treatments. Both compounds increased the vase life of tuberose cut flowers and CA at concentrations 100 and 200 mg dm⁻³ and H₂O₂ at concentrations 20 and 40 mg dm⁻³ doubled this time up to 14-17 days.

Clerodendrum phlomidis L. f. is an important medicinal plant of the Lamiaceae family, particularly its roots, which are used for various therapeutic purposes in a pulverized form. The objective of this study was to develop a standard protocol for axillary shoot proliferation and rooting of C. phlomidis for its propagation and conservation. Nodal explants were inoculated on Murashige and Skoog (MS) medium that was supplemented with one of six cytokinins: 6-benzyladenine, kinetin, thidiazuron, N⁶-(2-isopentenyl) adenine (2iP), trans-zeatin (Zea) and meta-topolin. Callus induction, which was prolific at all concentrations, formed at the base of nodal explants and hindered shoot multiplication and elongation. To avoid or reduce callus formation with the objective of increasing shoot formation, the same six cytokinins were combined with 4 μM 2,3,5-tri-iodobenzoic acid (TIBA) alone or in combination with 270 μM adenine sulphate (AdS). Nodal explants that were cultured on the medium supplemented with 9.12 μM Zea, 4 μM TIBA and 270 μM AdS produced significantly more and longer shoots than on medium without TIBA and AdS. Half-strength MS medium supplemented with 8.05 μM α-naphthaleneacetic acid was the best medium for root formation. Most (75%) in vitro rooted plantlets were successfully acclimatized under natural conditions.

An efficient and reproducible micropropagation protocol of Solanecio biafrae (Oliv. & Hiern) C. Jeffrey has been developed from nodal stem segments. Shoot development was obtained on Murashige and Skoog (MS) medium supplemented with benzylaminopurine (BAP) alone and in combination with zeatin and 1-naphthaleneacetic acid (NAA). Elongated shoots were rooted in the presence of zeatin or 3-indole-butyric acid (IBA) alone or in combinations. The highest number of explants forming shoots (100%) as well as the highest number of shoots per explant (3.4) and the longest shoots (22 mm) were recorded on medium containing 4.0 mg·dm⁻³ BAP, 2.0 mg·dm⁻³ NAA, and 1.0 mg·dm⁻³ zeatin. About 76% of shoots formed roots on half-strength MS medium free of plant growth regulators. The best root formation (approximately 88%) was recorded on the medium containing 1.0-1.5 mg·dm⁻³ IBA. The micropropagated shoots with well-developed roots were efficiently acclimatized under greenhouse conditions. The random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) amplification products were monomorphic in micropropagated plants and similar to those of mother plant showing their genetic uniformity. This is the first report of micropropagation of S. biafrae, which will facilitate in vitro mass propagation, conservation, and germplasm exchange of this endangered African vegetable.

The aim of the study was to evaluate the influence of 1-methylcyclopropene (1-MCP) treatment and ultra-low oxygen (ULO) storage conditions on the sensory characteristics of apples. Two apple storage technologies were tested in this study: cold storage under traditional conditions in combination with 1-MCP treatment, and ULO storage with two different compositions of a gas mixture. Apples were stored for 6 months. After storage, the sensory characteristics were analysed. Sensory evaluation showed that storage technology affected the sensory characteristics and panelists’ acceptability. Distinctive differences were found between apples stored under controlled atmosphere and traditional conditions. Trained panelists highlighted that samples stored under controlled atmosphere had pronounced juiciness and color, while 1-MCP-treated apples stored in cold were sweeter and more aromatic. Apples of the autumn cultivar ‘Auksis’, was perceived considerably higher after harvest and before long-term storage, compared with other cultivars. During 6 months of storage in controlled atmosphere, the sensory quality of these apples remained intact. Also, the sensory quality of fruit of the winter cultivar ‘Sinap Orlovskij’ throughout 6 months of its storage in controlled atmosphere remained intact. Besides, it was noticed that apples stored in controlled atmosphere were juicier and more aromatic with intense color. There is a positive effect of 1-MCP treatment on maintenance of apple quality stored in normal atmosphere for 6 months. With regard to some quality parameters and sensory attributes, 1-MCP-treated apples stored under normal atmosphere are comparable to those stored under ULO conditions.

Investigations were carried out in 2008-2010 on Chinese cabbage (Brassica rapa L. var. pekinensis (Lour.) Olson). The main problem in cultivation of this vegetable is physiological disorder – tipburn. It is connected with low level of calcium in young leaves and with water deficiency. In 2008, seeds of Chinese cabbage were sown twice, in April and July. In July, the day temperature was high (25-30 °C) and relative air humidity was low (35-50%). In these conditions, the young leaves were injured heavily. Rotting was caused by the activity of bacteria Pectobacterium carotovorum subsp. carotovorum (Jones) Hauben et al. However, three times foliar application of 1.5% calcium nitrate or 1.5% Wapnovit significantly reduced the tipburn. Also spraying with 0.03% of Tytanit (containing ions of titanium) or with 2.5% of Biochikol 020 PC (containing chitosan) gave similar effect. In these conditions, application of 1.5% K-300 (containing potassium oxide and ammonium nitrate) exacerbated symptoms of tipburn. Application of Wapnovit or Tytanit reduced instantly rotting of heads contrary to the application of their mixture. In autumn cultivation, when the relative air humidity was 80-100%, spraying with 1.5% solution of K-300 significantly decreased injuries in comparison to control. Application of Wapnovit, K-300, Biochikol, Tytanit or the mixture of Biochikol and calcium nitrate eliminated rotting. In experiments done in the springs of 2009 and 2010, when weather conditions were less favorable for tipburn appearance, a severity of it was lower but application of K-300 increased it appearance. In these experiments, Biochikol and Wapnovit eliminated rotting of heads. The results of three years of study have shown that calcium nitrate, Wapnovit, Tytanit and Biochikol limited occurrence of tipburn and bacterial rotting of Chinese cabbage, but the weather conditions during cultivation had the greatest impact on the severity of tipburn.

The study presented herein concerns the effect of pre-sowing stimulation of scorzonera seeds with He–Ne laser on germination capacity, field emergence of seedlings and the content of chlorophylls and carotenoids. Seeds of scorzonera cv. ‘Duplex’, from harvests of various years, dis-played variable quality expressed by their germination capacity. They were subjected to pre-sowing stimulation with He–Ne laser light of the power of 40 mW and wavelength of 632.8 nm, surface power density of 5 mW·cm⁻² and different exposure times. Germination capacity on Petri dish test increased only in one lot of seeds after exposure for 1 and 5 min. Increase in seedling emergence in the field experiment in the result of laser treatment occurred only in one seed lot. One-min laser treatment increased contents of chlorophylls and carotenoids in 8-day cotyledons (laboratory test) and in the second true leaves (field experiment).

Cultivation of field tomato in Poland meets unfavorable temperature and precipitation conditions, which affect yield and quality. The aim of the study is to evaluate the effect of temperature and precipitation conditions on the growth and development dynamics of five cultivars of processing tomato. The analysis took into account the key morphological characteristics of the plant, the inflorescence and fruit, which determine the suitability of the cultivar for processing. Analysis of the effect of meteorological elements on the stem development showed that stem length was most strongly influenced by precipitation – both total precipitation and frequency, rather than by temperature; the greater the rainfall, the more intensive stem elongation. High levels of precipitation limited gains in stem thickness. The number of flowers and fruits formed per inflorescence was negatively correlated with temperature. Excessive precipitation during the entire growing period led to formation of smaller fruits. The length and width of the fruit were negatively correlated with the frequency of precipitation in all stages, and with total precipitation during the period from planting to setting of the first fruits. A beneficial effect of temperature on the length and width of the fruit was noted during the entire growing period. The tomato fruit formed a thicker pericarp when precipitation was more frequent.

To investigate the influence of deficit irrigation on the root-knot nematode, Meloidogyne javanica, and its interaction with the eggplant crop, field experiments were conducted at two drip-irrigated agricultural areas in Jordan. Effects of limiting irrigation levels to 80, 60, 40 and 20% of the field capacity (FC) were compared with full irrigation (100%) treatment. Growth of eggplant plants was greatly reduced at irrigation levels of 40 and 20% FC at one field location, suggesting that the influence of deficit irrigation is field-dependant. Fruit yield was similar at all irrigation levels, except at 20% level, where a lower yield was noticed compared to 100% irrigation. Root galling of eggplant caused by the nematode was significantly lower at irrigation levels of 20 and 40% than 80 and 100% of FC, but was field-dependant at 60% of FC. The final nematode population was obviously lower at irrigation levels of 20, 40 and 60% than 80 and 100%. Thus, deficit irrigation to levels of 40 or 60% of FC can be utilised for the management of M. javanica infection in eggplant under field conditions.

Amaranthus lividus is the most frequently reported troublesome weed in the production of Capsicum annuum in some regions because it is an aggressive invader, difficult to control, and reduces yield significantly. The effects of A. lividus on the growth of C. annuum ‘Baklouti’ were evaluated under greenhouse conditions. Three experiments were conducted to determine the effect of A. lividus on the biomass accumulation of C. annuum seedlings for 40 days. In an additive experiment, to one C. annuum seedling and 1, 2, 3 or 4 A. lividus seedlings were grown per pot. The second experiment was established to assess C. annuum intracompetition using from one to six plants per pot as the density. In a replacement experiment, C. annuum and A. lividus seedlings were transplanted into pots with different proportions of both plants (1/5, 2/4, 3/3, 4/2, 5/1). Competition by A. lividus reduced C. annuum plant dry weight by as much as 93%. However, C. annuum had little effect on A. lividus, reducing dry weight by 31.3% at a 5:1 ratio of C. annuum: A. lividus. Relative yield analysis between C. annuum and A. lividus demonstrated the competitive advantage of C. annuum over A. lividus. The relative crowding coefficient of both plants changed significantly in the presence of the other plant, at any ratio. The aggressivity of C. annuum was higher at its lower proportion and C. annuum was more aggressive towards itself than towards A. lividus when its density increased.

A study was carried out to evaluate the potential of exogenously applied potassium nitrate [1.0 g·dm⁻³ (K₁), 2.5 g·dm⁻³ (K₂) and 5 g·dm⁻³ (K₃)] plus gibberellic acid (GA₃) [0.005 g·dm⁻³ (G₁), 0.01 g·dm⁻³ (G₂) and 0.015 g·dm⁻³ (G₃)] on the growth and development of the cucumber (Cucumis sativus L.) ‘Seven Star F₁’ during various growth stages (40, 55 and 70 days after sowing). Treatment of plants with K plus GA₃ stimulated growth shortened the fruit maturation period and increased quality compared with non-sprayed control. The combination G₂K₂ resulted in maximum total yield, plant height, and total chlorophyll, phosphorus and nitrogen content in the leaves compared with other treatments. Fruit matured significantly earlier in plants sprayed with G₂K₂. Total yield and fruit quality dry matter, total suspended solids and antioxidant activity percentages were significantly higher in sprayed plants compared with controls. Potassium content in leaves and fruits reached the maximum level with G₃K₃ treatment. The results clearly showed that the foliar application of G₂K₂ proved to be the best choice for growing cucumber in terms of quantity and quality of yield.

Sclerotinia sclerotiorum (Lib.) de Bary is considered as one of the most harmful soilborne pathogens, which reduces productivity of horticultural crops. Currently used chemical or biological methods for the eradication of S. sclerotiorum from a soil are not very effective. The aim of this study was to evaluate the possibility of eradication of S. sclerotiorum sclerotia from a soil using the Trichoderma isolates, which were multiplied on the organic carriers prepared from agro-industrial wastes and by-products: WsA (wheat straw + apple pomaces), WsP (wheat straw + potato pulp) and T-GRAN (dry onion rind, apples and strawberry pomaces, rapeseed meal). The results showed that soil amendment with organic materials overgrown with the Trichoderma fungi had a significant reducing effect on S. sclerotiorum. Especially effective was the carrier WsA overgrown with T. virens TRS114, which completely prevented the survival of sclerotia of S. sclerotiorum regardless of the dose of application. Less effective was the WsP carrier. However, addition WsP overgrown with T. atroviride TRS40 at the 5% w/v, resulted in survival only 6.7% of sclerotia. In the greenhouse experiments with lettuce, the application of granulates T-GRAN into the soil had different impact on S. sclerotiorum depending on the conditions to the pathogen development. In conducive conditions, an addition of the organic substances without Trichoderma significantly decreased the yield of lettuce plants. A positive effect on the growth of plants was observed after the application of T-GRAN overgrown with Trichoderma.

The aim of these studies was to develop an effective formulation for microbial strains active in plant protection. Emulsification technique in oil was used to produce alginate microcapsules supplemented with organic additives to improve production process and stability of the preparations during storage. The release of microorganisms from the capsules in soil and their effectiveness in biocontrol of Fusarium wilt were evaluated. Three bacterial strains Burkholderia cepacia strain CAT5, Bacillus spp. strains PZ9 and SZ61, and fungus Trichoderma virens TRS106 were immobilized separately in calcium alginate supplemented with chitosan, peat powder, or skim milk. The productivity of microcapsules was enhanced by 60% when peat was added to the alginate matrix. Peat reduced also contamination of the capsules during storage, significantly enhancing their quality. By contrast, the addition of skim milk reduced quality of the microcapsules. The additives did not influence the viability of entrapped microorganisms and their release in soil. The survival of the microbial cells was mainly related to the kind of microorganism used, and the highest viability showed Bacillus sp. PZ9 and Trichoderma TRS106. Lyophilization of the microcapsules appeared to be unfavorable by reducing microbial viability in the capsules and in the soil after application. The best properties: good storage ability and sufficient microbial release in the soil, exhibited wet microcapsules amended with peat. These capsules were used to control Fusarium wilt in tomato plants. The protective effect was obtained when the microcapsule-entrapped bacteria PZ9 were used. The effectiveness of this bacterium was comparable with fungicide. Peat-amended microcapsules entrapping Bacillus PZ9 showed the best quality and may have potential for commercial use.