Researchers compared the heat tolerance of six types of rice by growing them in different temperatures during the grain-filling stage. They found that high temperatures affected the rice's starch properties, such as amylose content and gelatinization temperature. Some varieties were more tolerant to heat than others, with Huanghuazhan being the most heat-resistant and Y liangyou NO 1 being the least. Certain starch properties, like amylose content and gelatinization enthalpy, were more sensitive to high temperatures and could be used to evaluate heat tolerance in rice varieties.