High temperature/heat

Temperature regulates the process of photosynthesis; if temperature exceeds the critical level, which occurs when there is an elevation of 10-15 ⁰C in ambient temperature is known as heat shock.
Heat tolerance studies in rice mainly deal with the reproductive stage as it is highly sensitive and influences grain yield. It affects the pollen viability, pollen production, dehiscence of the anther, pollen shedding.
Heat tolerance rice varieties has certain physiological and morphological traits like; early maturity, quick regeneration capability, fast recovery from heat, flexibility in accumulation, and translocation of carbohydrate.