Evaluation of Wheat Genotypes for Grain Filling by Stem Reserves Utilization for Under Normal and Water Stress Conditions.

Evaluation of wheat genotypes for grain filling by stem reserves utilization for under normal and water stress conditions Abstract In order to study of wheat genotypes for stem reserves utilizing for grain filling under normal and water stress conditions, this investigation was conducted using split split plot design based on Randomized compeletly Block Design with 3 replication in agricultural and natural resources research station of Torogh, Mashhad at 2006-07 growing season. Water stress treatment in two levels: 1- Normal conditions (full irrigation) and 2- water stress assigned to main plots, Wheat genotypes treatment in 8 levels: 9103, 9116, 9203, 9205, 9207, 9212, C-81-10 and Cross Shahi genotypes were located in sub plots, and photosynthetic conditions with 2 leveles: 1- using of current photosynthesis and 2 Inhibition of current photosynthesis were in sub-sub plots. Water stress imposed by cutting of irrigation from anthesis to maturity stages.Also, for inhibition of current photosynthesis, Iodid potassium 0.4% solution were used. Results showed that, the effect of water stress on grain yield (GY), Thousands kernel weight (TKW), Plant height(PLH),No of kernel per spike (NKS), Spike length (SL), Peduncle length (PL) and dry weight of spike (DWS) in anthesis stage, were significant. There was a significant differences between genotypes for above mentioned traits.The 9103 genotype had the more NKS, the C-81-10 genotype had the highest D.W.S and Cross Shahi cultivar had the highest TKW and PLH. The 9103 genotype had the highest remobilization efficiency(Ree) and remobilization percentage(Rep). based on results of this experiment, under both irrigation conditions and using of current photosynthesis, 9116 and 9212 genotypes had the highest GY, but under full irrigation and inhibition of photosynthesis C-81-10 genotype and under water stress and inhibition of photosynthesis conditios, The 9116 had the highest G.Y .Finally, the 9116, 9212 and C-81-10 genotypes under different irrigation conditions had the high potential for reserves and remobilizations of assimilates.The genotypes with high yielding potential under different conditions of this experiment, had the more harvest index(HI) and NKS in comparison with the others genotypes. Also, solution method with potassium Iodid for evaluating of contribution of remobilized dry matter in wheat was the more simple and more percision method via conventional sampling method. Key words: Wheat genotype, water stress, remobilization of assimilates, solution, Potassium Iodid, yield.