Heat stress indices of wheat (Triticum aestivum L.) varieties as affected by sowing dates and growth regulators under sub-tropical conditions of Jammu
A field experiment was conducted during the rabi season of 2022–23 at the Research Farm, Division of Agronomy, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, to evaluate the effect of sowing dates, wheat (Triticum aestivum L.) varieties and plant growth regulators (PGRs) on yield and heat stress indices under sub-tropical conditions. The study involved three sowing dates, two wheat varieties and three PGR treatments in a split-split plot design. Results showed that sowing on 25 November recorded the highest canopy temperature depression (CTD), while 15 December sowing achieved the highest yield stability index (YSI). The variety DBW 303, particularly when treated with paclobutrazol, performed best in mitigating heat stress and achieving higher yields. Late sowing increased heat stress intensity and susceptibility, especially for variety JAUW 672 and untreated plots. It is concluded that, under the sub-tropical conditions of Jammu, sowing DBW 303 on 25 November with paclobutrazol application can enhance productivity and reduce the negative effects of heat stress.