Phenotypic and molecular characterization of bread wheat (Triticum aestivum L.) genotypes for terminal heat tolerance
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Date
2021-09
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CCSHAU, Hisar
Abstract
The present experiment was conducted to identify promising heat tolerant lines, in a core collection of forty-eight bread wheat accessions. The experiment was laid out in Randomized Block Design with three replications, under three dates of sowing viz., 25th October, 14th November and 15th December, at the Research Area of Wheat and Barley Section, Department of Genetics & Plant Breeding, CCS Haryana Agricultural University, Hisar during Rabi 2019-20. Observations were recorded for twenty-three morpho-physiological and biochemical traits viz., grain yield/plant (g), days to heading, days to anthesis, days to maturity, grain filling duration, tillers per metre, plant height (cm), peduncle length (cm), spike length (cm), spikelets per spike, number of grains per spike, 1000-grain weight (g), biological yield per plant (g), harvest index (%), normalized difference vegetation index at anthesis and 21 days after anthesis, canopy temperature at anthesis and 21 days after anthesis (⁰C), protein content (%), gluten content (%), sedimentation value (mL) and hectolitre weight (Kg/hL), flag leaf angle and waxiness. Significant variance among genotypes was recorded for all the characters, under all three environments. High GCV, PCV, heritability and genetic advance estimates were observed for biological yield, grain yield, CTD-I, CTD-II and sedimentation value in all the environments. Correlation coefficient and path analysis revealed that the traits i.e. biological yield, tillers per metre, harvest index, 1000-grain weight, CTD-I and CTD-II had strong positive association with grain yield, therefore, presenting them as key enhancer of grain yield in wheat under heat stress conditions. Cluster analysis showed high genetic divergence among genotypes and grouped them in different clusters. In stability analysis, genotypes WH 1235 and HD 3182 were found most stable ones, with respect to grain yield. Genotypes WH 1124, HD 3086, WH 730 were found to show high heat tolerance, based on HSI. Tillers per metre were the most affected trait under heat stress and witnessed highest reduction. Molecular analysis revealed the presence of high degree of polymorphism for the selected genotypes. Genotypes that turned out to be best for as maximum number of traits on as many numbers of statistical tests, should be included in breeding programme for crop improvement with respect to grain yield.