Vol. 8, Issue 9, Part N (2025)
Abstract
Heat stress poses a major constraint to wheat production by impairing grain yield and quality, particularly at the reproductive and grain-filling stages. The screening and detection of heat-tolerant genotypes plays a vital role in minimizing yield losses under heat stress. The experiment involved the assessment of ten wheat genotypes (Trimbak, NIAW-34, MACS-6222, MACS-6478, MACS-2496, RAJ-3765, Phule Samadhan, Sardar, HI-1633, HI-1605) grown during the 2021-22 season under three irrigated environments, timely sown (non-stress environment (S1), late sown (S2) and very late sown (heat stress environment, S3) at Post Graduate Instructional Farm and Botany laboratory, PGI, Mahatma Phule Krishi Vidyapeeth, Rahuri. Delayed sowing was used to impose heat stress as 20-20 days delayed from normal sowing date. Wheat genotypes were evaluated for heat tolerance on the basis of multiple morpho-physiological and biochemical traits such as days to first flowering, days to maturity, plant height, tillers per plant, length of spike, number of grains per spike, weight of grains per plant, 1000-grain weight, CTD, chlorophyll content, RLWC, SOD, TSI, and NDVI. Varieties HI-1605 and NIAW-34 showed superior traits, such as higher productive tillers, larger spikes, and improved grain weight even under late sowing conditions. Genotype HI-1605 exhibited higher chlorophyll retention, superior CTD, and better RLWC. HI-1605 and Phule Samadhan showed high SOD activity. Genotypes HI-1633, and NIAW-34 consistently demonstrated superior heat tolerance with low TSI values. Phule Samadhan and HI1605 consistently showed high NDVI values. Thus, these traits may serve as effective criteria for screening heat-tolerant traits in wheat.
