Genetic variability for terminal heat tolerance in advance lines of bread wheat (Triticum aestivum L. em. Thell)
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Date
2021-09
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CCSHAU, Hisar
Abstract
The present investigation was conducted to identify the terminal heat tolerant lines. The experiments were laid out in Rabi 2019-20 among the forty wheat advance lines taken for the study. Randomized Block Design with three replications was used, under two sowing dates (24th November and 24th December, 2019) at the Research Area of Wheat and Barley Section, Department of Genetics & Plant Breeding, CCS Haryana Agricultural University, Hisar. Observations were recorded for sixteen morpho-physiological traits viz., days to heading, days to maturity, plant height, number of effective tillers per meter, spike length, peduncle length, number of spikelets per spike, number of grains per spike, 1000- grain weight, biological yield per plant, harvest index, grain yield per plant, normalized difference vegetation index (NDVI) at initiation of anthesis and after 15 days of anthesis, soil plant analysis development (SPAD) value at initiation of anthesis and after 15 days of anthesis, canopy temperature depression (CTD) at initiation anthesis and after 15 days of anthesis and heat susceptibility index (HSI). The ANOVA revealed that variance due to genotypes were highly significant for all the traits, under both the conditions. Moderate to high estimates of GCV, PCV, heritability and genetic advance as percent mean were observed for traits viz., grain yield, biological yield, harvest index, number of grains per spike, spike length, peduncle length, number of effective tillers per meter, CTD and SPAD value. Correlation coefficients and direct path effects revealed that the traits i.e., biological yield per plant, harvest index, number of spikelets per spike, 1000-grain weight, NDVI, CTD and SPAD value had a true association with grain yield, whereas maximum indirect path were recorded for biological yield per plant and harvest index, hence these yield attributing traits could be considered as suitable selection criteria for wheat improvement programs under heat stress conditions. On the basis of heat susceptibility index lines viz., NW 7049, DBW 14, WH 1021, PBW 825, DBW 304 and PBW 797 were found highly terminal heat tolerant. These lines can be used for further development of terminal heat tolerant varieties in future breeding programs