EVALUATION OF STRESS SELECTION INDICES FOR MORPHOLOGICAL TRAITS IN BREAD WHEAT

Abstract

The research carried out under irrigated conditions during 2017–2018 estimated stress selection indices for morphological studies in wheat. Twenty wheat genotypes along with two checks (Pakhtunkhwa-2015 and Pirsabak-13) planted at Cereal Crops Research Institute (CCRI), Pirsabak Nowshera, Pakistan, had two sowing dates, i.e., regular plantation made on 24 November and late plantation on 25 December 2017, in a randomized complete block design with three replications. Nine stress tolerance indices, viz., tolerance index (TOL), mean productivity (MP), harmonic mean (HM), stress susceptibility index (SSI), stress intensity (SI), geometric mean productivity (GMP), stress tolerance index (STI), yield index (YI), and yield stability index (YSI) served as the basis for computation on each trait and every genotype under stress and non-stress conditions. Grain yield demonstrated a positive relationship with MP, GMP, HM, and STI under stress and non-stress conditions, which can serve as a better indicator for testing tolerant wheat genotypes. Overall, the maximum value of MP, HM, GMP, and STI, for days to heading displayed in genotype CDRI-PV-1: 113.00, 112.12, 112.56, 1.30; days to maturity in genotype PS-28 with 151.00, 149.24, 150.11, 1.28; for plant height in genotype PS-28 with 108.00, 107.94, 107.88, 1.27: for grain yield in cultivar PS-34 with 3983.89, 3958.96, 3934.18, 2.25, and for biological yield in genotype PS-23 with 11250.00, 10999.44, 10754.46, and 1.80, which specify that they are most stable and tolerant genotypes across both the planting conditions. Analysis of variance revealed highly significant differences among genotypes for most traits. Based on stress selection indices and mean performance in this experiment, PS-23, PS-33, PS-34, and PS-28 genotypes showed the best performance, and genotype Inq-91/FS(f8) resulted as the most stable performance and tolerance in stress conditions compared with other genotypes in stress selection indices. These genotypes could be beneficial in future wheat breeding programs to enhance the grain yield stability in bread wheat.