Grain growth and yield potential of wheat genotypes under late sown heat stressed condition

Abstract

This open field experiment was conducted to evaluate the adaptation of wheat genotypes in late sown heat stress condition. Grain growth, yield components and yield of four wheat genotypes (BARI gom 25, BARI gom 26, BAW 1135 and Pavon 76) was determined at different sowing dates. Sowing on 29 November was considered the normal growing period (control) with a mean air temperature 24.08 °C during the post anthesis stages. Mean temperature was as high as 28.4 °C on 30 December sowing which is heat stress condition for wheat. Under stress condition (30 December sowing), BARI gom 25 and BARI gom 26 continued to increase grain dry matter up to 32 days after anthesis (DAA) which stopped 8 days earlier in Pavon 76. Under post anthesis heat stress condition the higher number relative spike m⁻² (92%), higher relative grain number spike⁻¹ (92%) and higher relative 1000-grain weight (96%) were found in BARI gom 26 compared to Pavon 76. Higher yield reduction was recorded in Pavon 76 (78.06 kg ha⁻¹ d⁻¹) compared to BARI gom 26 (19.36 kg ha⁻¹ d⁻¹) on 30 December sowing. In terms of grain growth and seed yield, BARI gom 26 was found to be the superior variety for growing under warmer environment.