Genetic analysis of morpho-physiological traits in relation to heat tolerance in barley (Hordeum vulgare L.)

The subject of the current study was to assess heat susceptibility index with the aim to identify the heat tolerant genotypes, in addition to recognize the selection criterion for heat tolerance. Forty four barley genotypes were tested in two environments as created by different sowing dates i.e. timely sown (non-stress) and late sown (heat stress) during 2021-22 at CCS Haryana Agricultural University, Hisar. The genotypes namely BH 1018, IBON-HI-2021-52, BH 1036, DWRUB 64, 7^th GSBON-2020-101, IBON-HI-2021-102, IBON-HI-2021-85 andDWRB 123 were identified heat tolerant based on heat susceptibility index of grain yield. Further, results based on average of ranks of HSI of all traits illustrated the genotypes, BH1018,IBON-HI-2021-102, IBON-HI-2021-52, DWRB 209 and IBON-HI-2020-55 with high heat tolerance under stress condition. Correlation among HSI of different traits indicated significant positive association of grain yield per plant with days to heading and maturity, spike length, number of grains per spike, biological yield per plant, harvest index and NDVI 2, exhibiting the relevance of these traits for deciding the selection criterion for stress condition. The genotypes of cluster III portrayed better performance under stress condition for grain yield and other traits studied. The genotypes from this group could be utilized as promising breeding material intended to develop new heat tolerant barley varieties.