Exploring heat stress tolerance indices in barley genotypes based on grain yield

Abstract

The objective of present study was to assess the heat tolerance of barley genotypes using a set of six heat stress indices i.e. HSI, HRI, HTI, TOL, MP and GMP, estimated using grain yield. A panel of 44 barley genotypes was evaluated under normal (non-stress) and heat stress conditions during 2021-22 crop seasons with three replications in randomized block design (RBD) at Experimental Area, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar (Haryana). The genotypes, IBON-HI-2021-102, BH 1018, IBON-HI-2020-51, DWRB 123 and 7^th GSBON-2020-101 were found heat tolerant identified based on average rank of stress indices employed on grain yield. Grain yield under stress condition (Y_s) showed significant positive correlation with the indices viz., HRI, MP and GMP while, it was negatively correlated with HSI. The association study signifies HRI, MP, GMP and HSI as the best selection criterion for heat stress tolerance. PCA study considered second principal component (PC 2) as heat tolerant component based on strong correlation with HRI, HTI and grain yield (Y_s) under stress condition. The genotypes of cluster IV portrayed better performance under stress condition for grain yield and other stress indices. The genotypes from this group could be utilized as promising breeding material intended to develop new heat tolerant barley varieties.