Effect of stomatal characteristics on photosynthesis and yield of the bread wheat chromosomal substitution lines under normal and stress conditions

This study was conducted to determine the effects of stomatal size and frequency on stomatal conductance, photosynthesis rate and yield, and to locate the genes controlling these traits. Therefore, substitution lines series of ‘Timstein’ (Tim) into genetic background of ‘Chinese Spring’ (CS) were tested in a completely randomized block design with three replications under two normal and water stress conditions in Shahrekord University research farm. Stress condition was started at elongation stage and irrigation periods were scheduled based on pre-determined ‘Growth Degree Day’ (GDD) during the length of stress period. Significant differences were found among substitution lines in terms of stomatal frequency, stomatal size, stomatal conductance, photosynthetic rate and yield. The significant correlation was found between the yield with stomatal size (r = 0.450**) and stomatal frequency (r = 0.461**) in stress and non-stress condition, respectively. In addition, there were significant correlation between yield with photosynthetic rate (r = 0.556** in stress condition and r = 0.482** in non-stress condition) and stomatal conductance (r = 0.247** in stress condition and r = 0.457** in non-stress condition). Based on the obtained results, it can be concluded that role of group B chromosomes was more prominent than the other two groups.