Quantitative and molecular characterization for heat tolerance in wheat (Triticum aestivum L. em. Thell).
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Date
2020-02
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CCSHAU, Hisar
Abstract
The present study was carried out to evaluate 96 advanced recombinant inbred lines derived from a cross
WH 730 (heat tolerant) and WH 147 (higher yielder, heat susceptible) to find out physio-morphological
traits and quantitative trait loci (QTLs) associated with heat tolerance in bread wheat. The experiment was
conducted in augmented design and randomized complete block design (RBD) during Rabi season of 2014-
15, 2015-16 and 2016-17 in the Department of Genetics and Plant Breeding, CCS Haryana Agricultural
University, Hisar. Analysis of variance revealed significant differences for all traits studied among the RILs.
Medium to high values of GCV, PCV, heritability and genetic advance as percent of mean for grain yield per
plant, number of grains per spike,100-grain weight, biological yield, canopy temperature depression and cell
membrane thermostability under either one or both environments over the years indicating a high scope of
selection for these traits for heat tolerance. Grain yield was significantly and positively correlated with
number of tillers per plant, harvest index, biological yield per plant, 100-grain weight, canopy temperature
depression, cell membrane thermostability and osmotic potential, whereas negative and significantly
correlated with days to heading and days to maturity under timely and late sown conditions over the years.
Biological yield and harvest index had high direct and indirect effects on grain yield per plant over
environment and years, indicating the true relationships with grain yield, in this set of material. Nine
promising RILs namely RIL No.46, 22, 40, 43, 57, 19, 48, 81, 71 and 88, out of 96 were identified for the
traits i.e., 100-grain weight, harvest index, grain yield, canopy temperature depression and cell membrane
thermostability related to heat tolerance under heat stress condition. Two RILs 22 and 40 showing better
performance over the environment and year. Twenty-six, out of 81 SSR markers used were found
polymorphic in parental genotypes and in RILs. Composite interval mapping (CIM) identified quantitative
trait loci (QTL) with significant phenotypic variation for number of spikelets per spike, spike length and
biological yield per plant along with heat susceptibility index (HSI). QTL identified for biological yield per
plant reported maximum phenotypic variation (50.0%) followed by spike length (46.37%) and number of
spikelets per spike (12.59%).