Effect of drought stress on dry matter remobilization and grain yield of winter bread wheat genotypes

To examine the effect of water stress on grain yield and remobilization of dry matter in winter bread wheat genotypes, two field experiments were conducted in Agricultural Research Station of Miandoabin West Azerbaijan in 2007-2008 and 2008-2009 cropping seasons. Treatments were arranged as split plot based in complete randomized block design with four replications. Irrigation levels (irrigation after I =70, I2=100, I3=130 and I4=160 mm evaporation from Class-A pan) were assigned to main plots, and 10 winter bread wheat genotypes (Zarrin, Alvand, Shahryar, Sardari, C-80-4, C-81-10, C-81-4, C-83-3, Zareh and Pishgamwere randomized in subplots. The highest grain yield was obtained for cv. Zarrin (6950 kg.ha 1) in well-watered and for Pishgam (4422 kg.ha-1) in severe water deficit conditions. Results showed that there were significant differences between genotypes in remobilization of stem dry matter. Severe water deficit increased the remobilization of stem pre-anthesis reserved assimilates by 23%. Pishgam cultivar had the highest remobilization (41%) under severe water deficit conditions. The positive significant correlation between grain yield and grain weight, harvest index and remobilization of dry matter, indicated that these traits can be used for identifying drought tolerant high yielding genotypes in winter wheat breeding programs.