水稻耐热新种质R203的创制与应用

【目的】全球气候变暖导致水稻抽穗开花期受到高温热害的影响日益严重。鉴定抽穗期耐高温水稻种质，创制耐热新种质，为培育实用性耐热水稻新品种，降低高温热害对水稻生产的影响，保障中国乃至世界的粮食安全奠定基础。【方法】以广恢128（七桂早/测64//明恢63）为耐热亲本，通过杂交、复交以及系谱法，选育过程中连续多代筛选抽穗开花期处于高温阶段结实率较高且变异较小的株系，在高世代，利用人工气候室进行抽穗开花期耐热鉴定（处理盆栽于开花当天移入人工气候室，高温处理时间段为每日09:00—15:00，设置恒温38℃，15:01—次日08:59设置恒温28℃，相对湿度均为75%，处理7 d），结合农艺性状分析方法创制水稻耐热新种质。【结果】创制的新种质R203具有较好的耐热性，在正常条件下和高温条件下都有较高的结实率（常温结实率为94.5%、高温结实率为81.9%、相对结实率为86.7%），其对三系不育系恢复能力强，综合抗性好，稻米品质优，具有配制实际应用价值的耐热新组合的潜力。在自然高温条件下，以R203为父本、7个三系不育系为母本配制的杂交组合结实率为83.4%—99.4%，耐热性均表现较好。其中，育...

Breeding and Application of a New Thermo-Tolerance Rice Germplasm R203

【Objective】 The global warming has led to the increasingly serious heat damage on the heading and flowering stage of rice. To reduce the impact of heat damage on rice production and to ensure food security in China and even the world, new rice germplasms with thermo-tolerance on heading stage should be identified and new thermo-tolerance varieties need be bred. 【Method】Guanghui 128 (Qiguizao/Ce64//Minghui 63) was used as the heat resistant parent, through hybridization, multiple crossing and pedigree selection, the lines with high seed setting rate and small variation on heading and flowering stage during the high temperature were screened out for several generations’ breeding process. Then the selected higher generation lines were identified to create new thermos-tolerance rice germplasms in artificial climate chamber (The treated plants will be moved into the chamber on the flowering day, high temperature treatment is 9:00-15:00, 38℃, 15:01-8:59 28℃, the relative humidity is 75%, and the treatment lasts for 7 days), with analysis of agronomic trait. 【Result】The new germplasm R203 has stronger thermo-tolerance and higher seed setting rates under both normal and high temperature conditions (94.5% at normal temperature, 81.9% at high temperature, and 86.7% at relative). Its agronomic traits, quality and comprehensive resistance all meet the production standards. Above all, R203 has the potential to breed new thermos-tolerance hybrid rice varieties. The seed setting rates of 7 hybrid combinations with R203 as the male parent and seven three-line male sterile lines as the female parent were between 83.4%-99.4% under natural high temperature conditions. Among them, Taiyou 203, a new three-line medium indica hybrid rice has good qualities, the seed setting rate was 87.9%, the comprehensive relative heat resistance coefficient was 1.11, and the heat resistance reached level 1. In the production test, the yield increased by 5.36% compared with the control, and the yield increase point accounted for 85.71%. It has good high and stable yield, and the rice quality reached the second level of the ministerial standard. Thus Taiyou 203 has good promotion and application value. 【Conclusion】Currently, basic research on heat resistance is not enough to support the breeding of new practical heat resistant varieties, the rice resources in areas prone to high temperature and humidity are preferred as materials for breeding new heat tolerance lines, a new heat-resistant rice variety R203 was created by phenotypic selection, and a practical heat-resistant rice variety Taiyou 203 was developed by using heterosis.