IMPACT OF SOWING TIME AND FOLIAR SPRAY OF OSMOPROTECTANTS ON GROWTH, YIELD ATTRIBUTES AND YIELD OF WHEAT (TRITICUM AESTIVUM L.) AGAINST HEAT STRESS

A field experiment was conducted on medium black calcareous soil during rabi seasons of 2020-21 and 2021-22 at the Instructional Farm, Department of Agronomy, College of Agriculture, Junagadh Agricultural University, Junagadh to evaluate the impact of sowing time and foliar spray of osmoprotectants on growth, yield attributes and yield of wheat (Triticum aestivum L.) against heat stress.The experiment was laid out in split plot design with three replications.The experiment consisting of sixteen treatment combinations, comprising four levels of sowing time (4 th week of October, 3 rd week of November, 1 st week of December and 3 rd week of December) were assigned to main plots and four levels of foliar spray of osmoprotectants (water spray, salicylic acid (SA) @ 100 ppm, sodium nitroprusside (SNP) @ 400 g/ml and KNO 3 @ 2.0%) were assigned to sub plots.The results of experiment on pooled data based indicated that among sowing dates, the wheat sown on 3 rd week of November recorded significantly higher initial (31.06) and final (29.64) plant population per meter row length, growth parameters viz., plant height at harvest (96.52 cm), dry matter accumulation at harvest (20.91 g/plant) and number of tillers per plant (4.02), yield attributes viz., number of spikes per plant (3.30), number of spikelets per spike (19.198), number of grains per spike (51.31), length of spike (9.59 cm) and test weight (44.86 g), grain yield (5445 kg/ha), straw yield (7433 kg/ha) and biological yield (12878 kg/ha) as compared to rest of the sowing times.The foliar spray of salicylic acid @ 100 ppm at 50 and 75 days after sowing (DAS) significantly increased plant height at harvest, dry matter accumulation at harvest, number of spikes per plant, number of spikelets per spike, number of grains per spike, length of spike, test weight, grain yield, straw yield and biological yield compared to water spray but it remained at par with foliar spray of KNO 3 @ 2.0 %.Based on the results of two-year field study, it can be concluded that wheat crop sown during 3 rd week of November along with foliar spray of salicylic acid @100 ppm or KNO 3 @ 2.0% at 50 and 75 DAS was found effective for mitigating of heat stress by improving growth and yield attributes as well as achieving higher yield of wheat under South Saurashtra region of Gujarat.