A total of 10 000 M₄ individuals in Jao Hom Nil (JHN) mutant population was treated with high temperature (40 °C to 45 °C) during the day time (6 h) from the booting to the harvesting stages, and ambient temperature (33 °C to 35 °C) was used as the control. The results of screening and yield trials found that the mutant line M9962 had a high spikelet fertility of 78% under heat stress. In addition, the other mutant lines, including M3181 and M7988, had a spikelet fertility of approximately 70%. However, the JHN wild type, Sin Lek, RD15 and RD33 had very low spikelet fertility of 34%, 14%, 9% and 4%, respectively. The lower spikelet fertility at an elevated temperature resulted in a dramatic decrease of filled grain and contributed to a loss in 100-grain weight. M9962 is a potential genetic stock for use in a heat tolerance breeding programme. In addition, spikelet fertility at high temperature was representative of heat tolerance and can be used as a screening trait for heat tolerance during the reproductive phase on a large scale.

总计10000 M ₄从启动到收获阶段的一天时间（6 h），对高温（JHN）突变种群中的个体进行了高温处理（40°C至45°C），环境温度（33°C至35°C） C）用作对照。筛选和产量试验的结果发现，突变株M9962在热胁迫下具有78％的高小穗繁殖力。此外，包括M3181和M7988在内的其他突变株的小穗育性约为70％。然而，JHN野生型，Sin Lek，RD15和RD33具有非常低的小穗受精率，分别为34％，14％，9％和4％。在升高的温度下较低的小穗繁殖力会导致填充谷物的急剧减少，并导致100粒重的减少。M9962是用于耐热育种计划的潜在遗传种群。此外，