A study was conducted to quantify the effects of terminal heat stress on yield and component traits for two consecutive years under normal and late sown environments. Analysis of variance indicated significant differences among genotypes for most of the studied traits. Tiller/meter (T/M) and grain yield were the most affected traits (>30% reduction), whereas traits like grain filling rate (GFR), grain number per spike (GNPS) and thousand kernel weight (TKW) were less affected (<15%) under heat stress. The traits, viz. GFR, GNPS, TKW, T/M and spike weight, as well as the relative change in these traits exhibited positive and significant correlation with yield and yield stability index (YSI), while negative and significant correlation with heat susceptibility index (HSI) and kernel weight reduction percentage (KWR) under heat stress. Based on HSI, KWR, and YSI indices, genotypes WH 1021, NW 1014 and NW 2036 were identified as the heat tolerant, while HD 3086, HD 2967 and HD 3059 were identified to be highly productive under both normal and heat stress environments based on STI and mean yield across the environments. The above selected genotypes also showed high mean performance for GFR and TKW under heat stress and could be used for breeding wheat genotypes for heat tolerance.

中文翻译：

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基于农业形态和胁迫选择指标的小麦终端耐热性评价

进行了一项研究，以量化在正常和晚播环境下连续两年终末热应激对产量和成分性状的影响。方差分析表明，大多数研究性状的基因型之间存在显着差异。分蘖/米 (T/M) 和籽粒产量是受影响最大的性状（减少 > 30%），而籽粒灌浆率 (GFR)、每穗粒数 (GNPS) 和千粒重 (TKW) 等性状受影响较小(<15%) 在热应激下。特征，即。GFR、GNPS、TKW、T/M和穗重以及这些性状的相对变化与产量和产量稳定性指数（YSI）呈显着正相关，与热敏感指数（HSI）和热应激下的籽粒减重百分比 (KWR)。基于 HSI、KWR 和 YSI 指数，基因型 WH 1021、NW 1014 和 NW 2036 被确定为耐热，而 HD 3086、HD 2967 和 HD 3059 被确定在正常和热应激环境下均具有高生产力跨环境的 STI 和平均产量。上述选择的基因型在热胁迫下也表现出较高的 GFR 和 TKW 平均性能，可用于培育小麦耐热基因型。