Abstract

This study was carried out at the Seed and Plant Improvement Institute, Karaj (Iran) in 2007/2008 and 2008/2009 growing seasons to investigate the effects of two irrigation regimes (normal irrigation and no irrigation in post-anthesis growth stage) on grain yield of eight wheat cultivars (DM-81-6, DM-82-1, Bahar, DN-11, DN-7, Pishtaz, WS-82-9, and C-85-6). According to the results of variance analysis, it is clear that there is a significant difference among the testing cultivars in grain yield and yield components. It is a result of difference in grain yield reduction among genotypes under different irrigation regimes. DN-11 Genotype produced the highest grain yield under both irrigation regimes. The yield reduction of Bahar genotype was the highest under drought stress conditions. Based upon the result of stepwise regression analysis, the most important yield components were biological yield, harvest index, and 1000 grain yield.            

Key words: Wheat, terminal drought stress, grain yield, components yield, stepwise regression.