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A field experiment was carried out at the Research Station of Eghlid-Azad University Iran in two years (2007 and 2008), based on a randomized complete block design with three replications. Three saline irrigation water treatments: 1 control, 6 and 12 dS·m-1 were arranged as main plots and three hull-less barley cultivar (U46M, GIZA 129 and PV110) were used as subplots. The measured parameters were growth, yield components, glucose, starch and sucrose content, relative water content and photosynthetic parameters in flag leaves. The results indicated that the number of ear and grain per plant were reduced significantly by stress. Grain weight was less sensitive to stress. Biological and grain yields were decreased by stresses. Among the cv. U46M had the lowest and PV110 the highest grain and biological yield. Biological yield differences were related to lower plant height and tillers. The grain yield reduction was related to ear no. per plant and grain no. per ear reductions. Salinity stress caused reduction in starch and increased sucrose contents. There were no significant differences between cultivars in glucose content. There were high negative correlation between sucrose content and grain yield and positive correlation between grain yield and starch content.
In this study two sowing date in years 2007-08 (1 November as normal sowing date and 1 January as late sowing date) were used. Measurements of chlorophyll fluorescence, membrane thermo-stability, gas exchange parameters and carbohydrates content in two wheat cultivars (Dena as durum wheat and Roshan as bread wheat) at post- anthesis stage were recorded. Acquired thermo-tolerance showed significant variation in late sown conditions. It was inferred that durum wheat conferred less relative injury and greater thermo-tolerance possibly through maintaining cellular membrane integrity under high temperature stress. Data based on chlorophyll fluorescence revealed a reduction of mean value of both cultivars for Fv/Fm, in late sown conditions. There were not any significant differences in all measured traits between two experimental years. Heat stress, occurred in late sown condition, caused reduction in biological and grain yield, harvest index, number of seed per ear, ear length and grain weight of two cultivars. But these reductions in durum wheat were lower. Seed protein content of cultivars increased in late sowing date. There were significant differences between cultivars in protein content. The grain yield reduction in cv. Roshan was higher than Dena. It seemed that by increasing in fructan and glucose content, rather than starch content, durum wheat can cope on the heat stress better than bread wheat.
In 2017 growing season numerous examinations of Cosmos bipinnatus in Hormozgan province, Iran revealed the disease symptoms similar to those associated with phytoplasmas. Phytoplasmas were detected from all symptomatic plants by the specific polymerase chain reaction (PCR) utilizing phytoplasma universal primer pairs. Amplification, sequencing and blast analysis of 16S rDNA fragment (ca. 1.2 kb) demonstrated that C. bipinnatus plants were infected by a phytoplasma belonging to the 16SrII group. This is the first report of association of a ‘Candidatus Phytoplasma aurantifolia’-related strain with C. bipinnatus phyllody in Iran.
In order to evaluate morphological and physiological traits related to drought tolerance and to determine the best criteria for screening and identification of drought-tolerant genotypes, we grew two tolerant genotypes (MCC392, MCC877) and two sensitive genotypes (MCC68, MCC448) of chickpea under drought stress (25% field capacity) and control (100% field capacity) conditions and assessed the effect of drought stress on growth, water relations, photosynthesis, chlorophyll fluorescence and chlorophyll content in the seedling, early flowering and podding stages. Drought stress significantly decreased shoot dry weight, CO2 assimilation rate (A), transpiration rate (E), and PSII photochemical efficiency (Fv/Fm) in all genotypes. In the seedling and podding stages, PSII photochemical efficiency was higher in tolerant genotypes than in sensitive genotypes under drought stress. Water use efficiency (WUE) and CO2 assimilation rate were also higher in tolerant than in sensitive genotypes in all investigated stages under drought stress. Our results indicated that water use efficiency, A and Fv/Fm can be useful markers in studies of tolerance to drought stress and in screening adapted cultivars of chickpea under drought stress.
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