مطالعه ضرایب مسیر عملکرد دانه و اجزای عملکرد در گندم دوروم تحت شرایط تنش و عدم تنش رطوبتی

The purpose of this study was to describe the correlations between wheat grain yield (GY) and its components, under environmental stress and non-stress conditions, and recognition of the most effective yield components and their development stages in making interaction with the environment. Two generations of F3 and F4, produced from a cross between Oste-Gata (drought tolerant) and Massara-1 (susceptible) genotypes, were used for evaluation in two years (2005 and 2006) at Research Farm of Isfahan University of Technology, Isfahan, Iran. Analysis of correlation of yield and yield components showed that grain yield was significantly correlated with grain weight per spike, number of grains per spike and number of spikes per m2. Results of Tai analysis revealed that under stress, grain weight per spike and under non-stress condition, number of spikes per m2 had the highest direct effect on GY in both generations. Assay of genotypic components showed that under stress conditions, grain weight per spike and number of grains per spike, and under non-stress conditions, number of spikes per m2 had the highest effect on genotype × environment interaction and their developmental stages (grain filling, reproductive and pollination). In non-stress condition, spike number per m2 had the same effect. Analysis of environmental components indicated that the most environmental sensitive period of plant growth was grain filling stage. Large difference between early and late growth stages is related to high sensitivity of grain filling period and reproductive stage to environmental conditions and the occurrence of drought stress at reproductive stage. Therefore, trend of grain yield variations under stress conditions was affected by grain weight per spike and showed the highest amount of environmental interaction at its growth stage