Auxin Application at the Flowering Stage of Rice Alleviates the Negative Impact of Heat Stress on Spikelet Fertility and Yield Attributes

The reproductive stage of rice is vulnerable to heat stress, which reduces spikelet fertility and yield. Auxin significantly influences development, hence the research aimed enhance grain attributes in plants by exploring application efficiency Indole-3-acetic acid (IAA) 1-naphthaleneacetic (NAA) under stress. This study investigated effects IAA (10 μmol L−1) NAA (100 on rate six genotypes during flowering stage. Compared stress (HS) treatment, production yield per plant were higher 61.16%, 37.25%, 33.07%, 72.84%, 44.48%, 32.71% control, HS + NAA, treatments, respectively. In addition, panicle weight, primary branches number panicle−1, 1000-grains weight (p < 0.05) improved with conditions. enhanced photosynthetic transpiration rate, while contrarily, leaf temperature diminished. showed positive relationships (r = 0.64) plant−1 0.63). Additionally, had a strongly negative correlation −0.81) rate. auxin increased filled grains relationship 0.75) plant−1. variation among was dependent variety tolerance Overall, these findings indicate that exogenous can mitigate impact improve