Contribution of pollen grain osmoregulation, relative water content and stomata density on drought tolerance in 40 bread wheat (Triticuma estivum L.) cultivars
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Abstract: (4219 Views) |
The contribution of physiological traits such as osmoregulation capability of pollen grain, relative water content (RWC) and stomata density in flag leaf area to drought tolerance of 40 bread wheat cultivars was studied. To evaluate their effect of these traits on grain yield, two separate field experiments were designed and conducted in2010 at experimental farm of college of agriculture, Kerman Shahid Bahonar University, Kerman, Iran using randomized complete block design with three replications. Osmoregulation capability of pollen grain was simulated using the ratio of projected pollen grains area under water stress to normal conditions in solutions containing 50% and 30% polyethylen glycol (PEG) 6000, respectively. Analysis of variance showed that the effect of drought stress and cultivar on grain yield and physiological traits were significant. Drought stress decreased grain yield by %33 and RWC by%15.4, but increased stomata density of flag leaf area by %21. Osmoregulation capability of pollen grain in Azar-2, Dez, Azadi, Hamoon, Karaj-3, Sabalan and Omid was greater than one, therefore these cultivars were identified as capable cultivars for osmoregulation. Osmoregulation capability of pollen grain showed highly significant correlation with grain yield under stress conditions (r=0.41**). Thus, this mechanism directly contributed to increasing grain yield under drought stress. Stress Tolerance Index (STI) was also used for identification of drought tolerant genotypes. Based on this index, cv. Azar-2 was identified as the most drought tolerant genotype. This cultivar had also the highest osmoregulation capability. It can be concluded that pollen grain osmoregulation is a likely mechanism contributing to drought tolerance of cv. Azra-2. |
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Keywords: Bread wheat, Drought stress, Physiological traits, Stomata density and Stress tolerance index |
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Type of Study: Scientific & Research |
Subject:
Special Received: 2015/02/16 | Accepted: 2015/02/16 | Published: 2015/02/16
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