بررسی امکان غربال ژنوتیپ‎های گندم متحمل به گرمای پایان فصل با آزمون پایداری غشا در برابر گرما

This study was carried out to evaluate the cell membrane thermostability as a method for selection of wheat tolerant to terminal heat stress at seedling and anthesis stages of ten medium maturity spring bread wheat genotypes under controlled conditions. The grain yield reduction under terminal heat stress conditions was measured in two separate experiments by applying two optimum (12 Nov.) and late (21 Dec.) sowing dates under field conditions in Ahwaz and two temperature treatments i.e. normal and heat stress from 10 days after anthesis to maturity in phytotron. In both seedling and anthesis stages, there was significant variation among the genotypes for cell membrane thermostability. The results of cell membrane thermostability were correlated (r=0.76) in both stages of seedling and anthesis. Hence, the results of cell membrane thermostability at seedling stage can be used to predict the thermotolerance of the fully developed plant. In late sowing date, percentage of reduction grain yield had significantly negative correlation with cell membrane thermostability in both stages of seedling (r=-0.68) and anthesis (r=-0.60). But, under heat stress conditions in phytotrone, these relationships were weak. It seems that cell membrane thermostability alone cannot be used as a selection criteria in breeding programs.