مشخصات پژوهش

This study was conducted to evaluate the physiological indices in relation to screening of rapeseedgenotypes fordrought tolerance, and to study seed yield and seed yield components under early and late season drought stress. Sixrapeseed genotypes were evaluated under non-stressed and water deficit conditions during rosette and seed fillingstages. The experiments were conducted in East Azarbaijan Agricultural and Natural Resources Research andEducation Center, Iran for 2 years (2010-2011 and 2012-2013). According to the results, canopy temperature (Tc)was increased, stomatal conductance (Kl) and relative water content (RWC) were decreased significantly by droughtstress during the rosette and seed filling stages. Correlations among the aforementioned physiological traits at seedfilling stage with each other and with seed yield were significant. It seems that these physiological traits can reflectthe drought effects in rapeseed genotypes. Among the genotypes, significant differences were observed for Klat seedfilling and RWC at rosette stages. While, Okapi and Licord having the highest seed yield, presentedthe highest Klduring seed filling and RWC at rosette stages.Therefore,Tc, Kland RWC can be used to screen rapeseed genotypesfor tolerance todrought stress. Drought stress during the seed filling stage significantly decreased plant height, thenumber of siliques per plant, 1,000-seeds weight and seed yield. Results of path analysis indicated that plant heightand yield components indicated positive direct effect on seed yield. Plant height had the highest direct effects on seedyield. Among the genotypes, Okapi and Licord were more suitable for cultivation in normal and drought conditions.