Evaluation of heat stress tolerance diversity in a number of rice genotypes on yield and yield components in Sistan and Baluchestan province

In the 2016-2017 crop year, an experiment was conducted in Irandegan, Khash city, Sistan and Baluchestan province under heat stress conditions in a split plot design in randomized complete blocks with three replications to investigate the effect of heat stress on yield and yield components of a number of rice cultivars. The main factor was the use of Shafaq, Shiroodi, Basmati, and Hir cultivars, while the sub-factor was planting on April 9th, April 30th, and May 22nd. According to the results of the analysis of variance, the interaction of cultivar with planting date affected straw weight, flag leaf length, grain weight, 1000-seed weight, grain yield, production efficiency, percentage of inoculated seeds, percentage of hollow seeds, and percentage of gypsum seeds. Plant height and spike length also differed significantly across varieties. In addition, planting date and cultivar had an effect on the quantity of seeds per sike. The highest straw weight (2046.3 g/m2) was obtained on April 30th in the Basmati cultivar, the highest grain yield (5688.7 kg / ha) on May 22nd in the Shafaq cultivar, the highest percentage of inoculated seeds (89.7 percent) on May 22nd in the Hir cultivar, and the highest percentage of gypsum seeds (73.33 percent) on May 22nd in the Basmati cultivar. In the face of heat stress, the Shafaq cultivar maintained a satisfactory yield. According to the findings, the greatest yield is associated with May 22nd, and the best cultivar to suggest growing in the area based on the highest yield is Shafaq.