江西省早稻品种抽穗扬花期耐热性鉴定评价研究

Evaluation of Heat Tolerance at the Heading-flowering Stages for Early-season Rice Varieties in Jiangxi Province

在自然条件和人工温室模拟极端高温胁迫下对江西省生产上推广种植的37份早稻品种进行抽穗扬花期耐热性鉴定评价。以高温胁迫下结实率和结实率降低率为评价指标,对参试品种的耐热性进行综合评价。方差分析结果表明,杂交水稻组合间在自然条件和高温胁迫下结实率及结实率降低率接近显著水平,说明杂交水稻组合间耐热性存在一定的差异;而常规水稻品种间在自然条件和高温胁迫下结实率及结实率降低率差异不显著,说明常规水稻品种间耐热性的差异较小。2013年高温胁迫下平均最高气温(41.3℃)比2012年高0.9℃的情况下,杂交水稻平均结实率比2012年降低8.9%,而常规水稻平均结实率仅降低1.72%,常规水稻平均结实率的降低幅度明显低于杂交水稻;常规水稻品种的耐热性强于杂交水稻组合。2013年自然条件下最高气温(36.8℃)比2012年高1.3℃,但杂交水稻和常规水稻的平均结实率反而比2012年分别高5.6%和15.0%,这可能是由于2013年自然条件下相对湿度(81.4%)比2012年高(高14.4%)所致,说明气温高于适宜的生育温度时,相对湿度的增加有助于增强水稻品种的耐热性。五丰优623、陵两优611、株两优819、株两优312等4个杂交水稻组合和湘早籼7号、嘉育948、中早35、中早25等4个常规稻品种在高温胁迫下表现为较高的结实率且结实率降低率较低,认为可作为耐高温水稻品种在水稻生产和育种中加以利用。

Heat tolerance at the heading-flowering stages for 37 early-season rice varieties released in Jiangxi province,were evaluated under natural and high temperature conditions. Heat tolerance of rice varieties was evaluated using seed setting rate（ SSR） and its reduced rate under high temperature. The result showed that the F values of variance analysis for SSR under nature and high temperature conditions and its reduced rate in hybrid rice combinations were close to significant level,which meaned that there were definite difference of heat tolerances among hybrid rice combinations. While,the F values of variance analysis for SSR under nature and high temperature and its reduced rate in conventionality rice varieties were no significant,which meaned that there were a very smaller difference of heat tolerances among conventionality rice varieties. The average of SSR for hybrid rice combinations in2013 was reduced than 2012 for 8. 9%,while the average of SSR for conventionality rice was only reduced 1. 72%than 2012,when the average of maximum temperature（ 41. 3℃） under high temperature stress was more than 2012 for 0. 9℃,the reduced rate of SSR for conventionality rice was obviously lower than hybrid rice combinations. Therfore,the heat tolerance of conventionality rice were stronger than hybrid rice combinations. In natural condition,the average maximum air temperature of 2013 was 36. 8℃,higher than 2012 for 1. 3℃,but the average SSR of hybrid rice combinations and conventionality rice were more than 2012 for 5. 6% and 15. 0%,respectively. This results were caused by the relative humidity（ 81. 4%） of 2013 in nature condition,which was higher than 2012 for 14. 4%.It indicated that the high tolerance of rice varieties would become stronger with the increase of relative humidity,when the air temperature was higher than suitable growth temperature. Four hybrid rice combinations of Wufengyou623,Lingliangyou 611,Zhuliangyou 819,Zhuliangyou 312,and four conventionality rice of Xiangzaoxian 7,Jiayu948,Zhongzao 35,Zhongzao 25 were showed more SSR and smaller reduced rate under high temperature stress,which could be used in rice production and breeding with heat tolerance.