JWSS - Journal of Water and Soil Science

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In order to investigate the androgenic response of chickpea cultivars, two Iranian Chickpea cultivars, Pirooz and Karaj 12-60-31, were used in this study. After 7 to 10 days of cold pretreatment of flower buds, anther containing uninucleate stage of microspores were placed aseptically on MS medium supplemented with various combinations of growth regulators of 2,4-D (1,2 and 3 mg/l) and kinetin (0.1, 0.2 and 0.5 mg/l). Callus regeneration achieved using MS and modified Blayd’s media with various hormones and different sucrose concentrations. The results indicated that the callus initiation was significantly affected by 2,4-D and kinetin concentrations, and that increasing these hormones reduced callus induction. The best response obtained on media with the lowest concentration levels of 2,4-D and kinetin (1 and 0.2 mg/l, respectively). A highly significant genotypic effect and a genotype  2,4-D interaction were detected, which proved that Pirooz response was the best. Callus differentiation and organogensis occurred in MS medium supplmented with NAA, BA and 3% sucrose. Mature embryos also obtained in modified Blayd’s plus 0.5 mg/l kinetin and 10% sucrose. Cytological studies revealed the presence of haploid cells with chromosome variation in the anther derived callus. Therefore, optimizing the hormone levels of different basal media with a particular sucrose cocentration may improve haploid regeneration in chickpea. It seems a further study should be carried out to characterize calli from induction to regeneration and to determine the effect of cold pretreatment, the results of which could be used to improve anther culture response of chickpea.

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A 2-year vineyard survey failed to the provide evidence that Uncinula necator (Schw.) Burr. survived winter as mycelium in dormant infected buds in Khorassan province. Ascospores of U. necator, were collected by a volumetric spore trap operating constantly in a vineyard for 55 days after the bud burst. The first powdery mildew colonies were consistently found on the leaves of the shoots (7.30 cm long) growing on the vine. Cleistothecia were found on all plant parts infected during the previous growing season. More than 35-45 % of the cleistothecia borne on the leaves and stems died during winter. Most of the ascospore discharge occurred between the bud burst and the blooming time. Ascospores were periodically released from cleistothecia on the leaves kept in vineyard from October to May, while the ascospores germinating on the glass slides germinated from October to January and then germination slowed down to zero in early March and the water content potential of ascospore cytoplasm decreased constantly during this period as well. The mass required to fracture the ascocarp wall during maturation was measured to be approximately 5g in autumn, 3g in winter and 2.5 g in early spring. The most rapid decrease in the strength of the ascocarp wall occurred during a 4-week period before dehiscence in the field. The effect of the pathogenic property ascospores on healthy leaves demonstrated their role as a primary inoculum source. Cleistothecia appear to be the principal means of overwintering of U. necator in Khorassan province vineyards.

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Drought stress is one of the most important environmental stresses in reduce of growth and plants production. Determination of resistance mechanisms to environmental stress in plant improvement is very important. In order to , experiment with osmotic potentials of PEG (zero (control), -4, -8 & -12 bar) and alfalfa genotypes was done. The selected alfalfa genotypes namely, Yazdi(tolerant), Nikshahri(moderate) and Ranger(sensitive) were grown in hydroponic culture. After 4 weeks, they were harvested in order to determination of proline accumulation and Ca⁺², K⁺ and Na⁺ concentration. The data showed with increasing of drought stress, proline accumulation were increased, but its rate was different among genotypes and organelles. Concentrations of K⁺, Na⁺ and Ca²⁺ increased with increasing of osmotic stress and there was significant different between genotypes. The K⁺/Na⁺ ratio in the shoots and roots of plant was decreased, when drought stress increased. Morphological and biochemical data showed Yazdi genotype was more tolerant to drought stress in compare with studied genotypes.