The effect of drought tension after pollination on some physiological characteristics and grain quality of different wheat genotypes

Much of the lands under wheat in the world is in arid and semiarid regions. In these regions the water requirement of wheat in all development stages can not be fully met. This research was conducted in this regard and in order to investigate the effect of post anthesis water deficiency tension on quantity and quality of grain yield and some physiological characteristics of wheat different cultivars. This experiment was conducted in the potted form as three-factors factorial for physiological traits and two-factors for yield quantity and quality and based on randomized complete blocks design with three replications at Campus of Agriculture and Natural Resource of Kermanshah Razi University during 2011-12 cropping year. Three investigated factors included: 1) humidity treatment in two levels of non-tension (field capacity) and water deficiency tension from pollination stage till the end of growing season (30 percentage field capacity), 2) different wheat genotypes (Pishtaz, DN-11, Sivand and Marvdasht) and 3) sampling date in two levels including: 11 and 17 days after anthesis. The results showed that in tension and non-tension water deficit conditions Marvdasht cultivar had the lowest grain yield. Among the other investigated genotypes (in two humidity conditions), Pishtaz had the highest grain yield. The lowest grain yield drop in water deficit conditions compared to non-tension was relared to Pishtaz cultivar, as well. Applying water deficit tension caused significant reduction of chlorophyll a and b concentration, total chlorophyll and carotenoids, maximum quantum yield of photo system II, viability index and relative water content. Also, water deficit tension caused decreasing in starch content and total dry mater and increasing in fiber content and grain protein of investigated genotypes.