Influence of Sowing Dates on Growth and Yield Dynamics of Wheat Genotypes under Heat Stress

The inexorable process of climate change in terms of the rise in minimum (night time) temperature delineates its huge impact on crop plants, while its effect on the yield and quality-related parameters of various crops. Recent studies have been conducted to examine the long-term influence of climatic variability on wheat output and propose adaptation techniques to mitigate its detrimental effects in India. The present study was conducted to determine the impact of sowing date and heat stress during the grain filling period on growth, yield components and quality-related traits of wheat genotypes. A pot experiment was conducted in the pot house of Baba Mastnath University, Rohtak, Haryana, during wheat season of 2020-2021 with ten genotype of wheat (C-306, HD-3086, NSGW-27, DBW-90, NSGW-9, WH-730, WH-1124, NSGW-1, RAJ-3765 and WH-1105) were assessed for growth and yield related attributes at three levels of sowing date i.e., OE (second week of November), HSE (third week of December) and EHSE (second week of January) in complete randomized block design with three replication to find out the suitable time of planting for each genotype. Spike length (cm) was measured by five independently selected plants at the maturation phase from every genotype for each replication in centimetres with the help of the ruler, and an average was derived. Triplicate data were analysed using OPSTAT software (accessible on www. http// hau.ernet.in.) for the complete randomised design (CRD), and CD at 5% was determined. Due to late planting conditions, plant organs and the transfer from source to sink were affected. Genotype varied from to 106.9 to 86.70 cm (plant height), 42.1 to 34.1 cm (peduncle length), 299.5 to 250.0 (peduncle fresh weight), 233.8 to 186.5 (penultimate fresh weight), 47.08 to 39.5 (no. of grain/spike), 12.43 to 5.8 cm (spike length), 2.49 to 0.88 (grain weight/spike), 18.68 to 14.48 (number of spikelet/spike), 38.5 to 23.8 grain filling duration and 9.7 to 6.8 (number of productive tillers/plant). In light of recent results, the wheat genotypes C-306, DBW-90, HD-3086 and NSGW-27 were identified as promising among all studied genotypes, which can be utilised for cultivation in areas subjected to heat stress and for further yield-related studies. This study was conducted to assess the effect of moderate to extreme heat stress on growth yield-related traits in wheat genotypes. These genotypes can be further employed to produce HEAT-resistant varieties, offering support in particular research fields and molecular studies for future prospects.