STUDY ON THE EFFECTS OF HEAT STRESS ON HSTU DEVELOPED ADVANCED LINES IN WHEAT (Triticum aestivum L.)

Abstract

The experiment was conducted with 11 wheat genotypes (10 HSTU-developed advance lines and 1 check variety) at Hajee Mohammad Danesh Science and Technology University, Dinajpur to identify heat tolerant genotypes during Rabi season, 2022-2023 in Randomized Complete Block Design with 3 replications. The analysis of variance revealed significant differences among the genotypes for most of the characters studied. Mean values of days to heading ranged from 51.67-69.33 days under optimum sowing (OS) and 59.33-66.33 days under late sowing (LS); days to maturity 102.33-121.33 days (OS) and 94.00-106.33 days (LS); plant height 92.35-116.33 cm (OS) and 91.76-115.67 cm (LS); number of grains per spike 30.93-45.20 (OS) and 34.27-47.90 (LS); spike length 8.58-10.73 cm (OS) and 9.25 10.05 cm (LS); number of spikes per square meter 351.67-505.67 (OS) and 332.33-440.00 (LS); grains weight per spike 1.32-1.88 g (OS) and 1.40-1.86 g (LS); 1000-grains weight 31.99-47.23 g (OS) and 30.23-47.04 g (LS); grains yield per plot 2087.2-2812.7 g (OS) and 2155.6-2751.0 g (LS). Judging the mean performance of 11 wheat genotypes it was observed that there may be some genotypes that were adapted to a heat-stressed environment and they could perform better even under heat-stressed conditions. In the study on the grain yield, yield contributing, phenological, and physiological characters, it was observed that the genotypes HSTUW8, HSTUW1, and HSTUW4 ranked better category for the maximum number of characters indicating their high tolerance to heat stress under heat stressed environment. In the study on the grain yield and stress indices, it was observed that the genotypes HSTUW8, HSTUW1, and HSTUW4 ranked better category for the maximum number of stress indices indicating their high tolerance to heat stress under a heat-stressed environment. 4 SSR markers (TaGwm291, TaXgwm294, TaBarc68, and Xgwm296) were evaluated in 11 wheat genotypes for molecular characterization and to identify the variation among the genotypes. A total of 28 alleles were detected and the number of alleles per locus ranged from 5-8 with an average of 7 alleles per locus. In population genetic structure analysis, population I consisted of 54.55% of the genotypes (6 genotypes: HSTUW4, HSTUW6, HSTUW7, HSTUW8, HSTUW9, and HSTUW10) where all the genotypes were pure. Population II consisted of 45.45% of the genotypes (5 genotypes: HSTUW1, HSTUW2, HSTUW3, HSTUW5, and BARI Gom 32) where all the genotypes were pure. The cluster analysis revealed two major clusters (Group I and II) with a similarity coefficient varying between 0 and 5 indicating significant genetic variation among the wheat accessions studied. In cluster I, the higher genetic similarity was observed among HSTUW4, HSTUW6, HSTUW7, HSTUW8, HSTUW9, and HSTUW10 were less genetic distances and genetically identical to each other. In cluster II, the highest similarity was observed between HSTUW1 and HSTUW2 were less genetic distances and genetically identical to each other, while the lowest similarity was observed between HSTUW5 and BARI Gom 32 were more genetic distances and genetically diverse.