高温热害已成为影响我国特别是长江流域水稻生长发育及高产稳产的主要限制因素之一。本研究利用大田自然高温、温室高温两种环境对2018—2020年的1 379份水稻材料的开花期耐热性进行了鉴定和评价，系统分析了不同年份间、不同品种类型间、不同来源渠道品种间耐热性情况。结果表明，供试材料中耐热性达到1、3、5、7、9级的品种比例分别为11.96%、66.78%、18.06%、2.76%和0.44%，且耐热品种呈逐年增多的趋势；两系杂交稻、三系杂交稻、常规稻中开花期耐热性达到强至较强（1级和3级）的品种占比分别为82.57%、73.45%和60.00%，不同类型品种的耐热性表现为两系杂交稻>三系杂交稻>常规稻；国家（省）区试、绿色通道、联合体渠道来源的品种的开花期耐热性整体表现相似。本试验综合利用大田自然高温、温室高温两种环境建立了一套水稻开花期耐热性鉴定规程和评价方法，可以对供试材料在不同年份、不同环境、不同程度热胁迫下的耐热性做出相对一致、客观的评价。

High temperature has become one of the main limiting factors affecting the growth and development of rice. In this study, totally 1379 rice varieties in recent three years were identified for heat tolerance at the flowering stage under natural field and greenhouse conditions, and the thermotolerance phenotype among varieties from different years, different types and sources was comprehensively analyzed. Among tested materials, 11.96%, 66.78%, 18.06%, 2.76% and 0.44% of them had the best （Grade 1）, good （Grade 3）, medium （Grade 5）, poor （Grade 7） and the worst （Grade 9） heat tolerance at the flowering stage, respectively; and the number of heat-tolerant varieties is increasing year by year. The overall situation of heat tolerance of different type cultivars was as follows: two-line hybrids > three line hybrids > conventional rice, in two-line hybrid rice, three-line hybrid rice and conventional rice, the proportion of varieties with heat tolerance above grade 3 at the flowering stage were 82.57%, 73.45% and 60.00%, respectively. The rice materials from national or provincial regional trial, green channel regional trial and alliance regional trial had similar heat-resistant performance. A set of identification method and assessment system have been established for rice heat tolerance at the flowering stage by adopting both natural high-temperature and artificial greenhouse conditions, which can make a relatively consistent and objective evaluation for heat tolerance of tested materials from different years, different environments and different degrees of heat stress.