Abstract:

【Objective】Our aim is to compare the resistance to rice blast of indica rice varieties identified from rice regional trials in the middle and lower reaches of the Yangtze River in China, and analyze the characteristics of six identification plots.【Method】Eight-hundred indica rice varieties (including 111 early-season indica, 468 mid-season indica and 221 late-season indica) were tested from rice planting regions in the middle and lower reaches of Yangtze River in China since 2013 to 2017. The resistance to rice blast (leaf blast and panicle blast) of the testing varieties was identified in six experimental plots distributed respectively in Zhejiang, Hunan, Hubei, Anhui, Fujian and Jiangxi Provinces.【Result】47.5% of all the 800 rice varieties showed moderately susceptible to rice blast, followed by the moderately resistant, susceptible and highly susceptible varieties to rice blast. While only 0.2% of the varieties were resistant, and no highly resistant variety was found. The resistance composite indexes in early-, mid- and late-season varieties were 4.95, 4.85 and 4.54, respectively, indicating that all types of varieties showed moderately susceptible to rice blast. Among the six experimental plots for resistance identification, the average composite index of all varieties in Zhejiang was the lowest. In Hubei, the leaf blast was the most serious; however, the loss rate of panicle blast was the lowest. The disease grade of leaf blast in Anhui was the lowest. The incidence of panicle blast was the lowest in Fujian. In Jiangxi, the incidence and the loss rate of panicle blast, and the composite index were all the highest. According to the composite index of all varieties, the moderately susceptible varieties were the largest proportion in Zhejiang, Hunan, Hubei, Anhui and Jiangxi, however, the varieties with middle resistance were the most in Fujian. According to the disease grade for the loss rate of panicle blast, the varieties with middle resistance to panicle blast were the most in Zhejiang, Hunan and Hubei. The moderately susceptible varieties were the most in Anhui. However, in Fujian, the resistant varieties were in the largest ratio. The proportions of different types of varieties were similarly in Jiangxi. 【Conclusion】The overall levels of disease resistance in indica rice varieties from the middle and lower reaches of the Yangtze River in China was in a low level. Same varieties showed different resistance levels in different identification plots, because the six plots possibly had their own characteristics. Thus the average resistance values for the tested varieties identified in the six plots are better to fully and objectively reflect the resistance levels of new rice varieties to rice blast.

Key words: indica rice, rice blast, resistance, middle and lower reaches of Yangtze River, regional trial

摘要：

【目的】旨在比较国家长江中下游稻区品种区域试验中籼稻稻瘟病抗性在六个省抗性鉴定点的表现及差异。【方法】试验材料为2013-2017年国家长江中下游稻区水稻品种区域试验的800个籼稻参试品种（其中早籼111个、中籼468个、晚籼221个）,在浙江、湖南、湖北、安徽、福建和江西共六个鉴定点进行稻瘟病（苗叶瘟和穗瘟）的抗性鉴定。【结果】800个籼稻品种中有47.5%表现为中感稻瘟病,其次为中抗、感和高感,表现为抗的品种所占比例只有0.2%,没有表现为高抗的品种。早籼、中籼和晚籼稻瘟病综合指数六点平均值分别为4.95、4.85和4.54,均属于中感水平。在六个抗性鉴定点中,浙江点综合指数最低,湖北点苗叶瘟最重、穗瘟损失率最低,安徽点苗叶瘟最轻,福建点穗瘟发病率最低,江西点穗瘟发病率、穗瘟损失率和综合指数均为最高。根据稻瘟病抗性综合指数分析,浙江、湖南、湖北、安徽和江西五个鉴定点均表现为中感的品种所占比例最大;福建点表现为中抗的品种所占比例最大。根据穗瘟损失率病级分析,浙江、湖南和湖北点均表现为中抗的品种所占比例最大;安徽点表现为中感的品种所占比例最大;福建点表现为抗的品种所占比例最大,且抗和高感的品种所占比例均为六点中最高,表现为感的品种所占比例为六点中最低;江西点各抗性类型品种的所占比例差异不大。【结论】国家长江中下游稻区水稻品种区域试验籼稻参试品种的稻瘟病整体抗性水平一般。相同的一套品种在不同的鉴定点表现有所不同,用各点的平均值评价参试品种的抗性可以充分、客观地反应参试品种对稻瘟病的抗性水平。

关键词: 籼稻, 稻瘟病, 抗性, 长江中下游, 区域试验