Abstract: Six pairs of primers, viz. RGA1(Resistance gene analog) (XLRR-for/ XLRR-rev), RGA2 (XLRR-inv1/XLRR-inv2), RGA3(NLRR-for/NLRR-rev), RGA4 (NLRR-inv1/NLRR-inv2), RGA5 (Pto-kin1/Pto-kin2) and RGA6 (Pto-kin3/Pto-kin4), were used to fingerprint 21 rice varieties based on RGA-PCR. Clustering analysis showed that the 21 varieties could be both classified into 5 groups at 0.72 similarity coefficient or using index of leaf blast severity at 0.84 level. Although there is no parallelism relationship between group and group in two different types of the clustering, the varieties, such as Xiangzi 3150, IR156, Zhuliangyou 02 and ZR02 with broad spectrum or durable resistance can be finely fallen into the same group. It was also suggested that 3 pairs among 6 primer pairs, viz. RGA1 and RGA2 designed from the LRR region of rice Xa21 gene and RGA3 from the LRR region of tobacco N gene, were more suitable to evaluate rice germplasms for their genetic responses to rice blast by RGA-PCR.

Key words: rice blast, resistant phenotype, resistance gene analog, similarity

摘要： 用6对RGA引物，即RGA1(XLRRfor/XLRRrev)、RGA2(XLRRinv1/XLRRinv2)、RGA3（NLRRfor/NLRRrev）、RGA4(NLRRinv1/NLRRinv2)、RGA5(Ptokin1/Ptokin2)和RGA6(Ptokin3/Ptokin4)对21个品种进行RGAPCR的DNA指纹分析。以相似系数0.72和田间叶瘟严重度阈值0.84分别聚类，21个水稻品种均可以分成5类。尽管类与类之间没有一一对应关系，但抗谱广、抗性稳定或具持久抗瘟性的品种，能较好地聚为一类，如湘资3150、IR156、株两优02、ZR02。在6对引物中，RGA1和RGA2来自于水稻抗白叶枯病基因Xa21含 LRR结构，RGA3来自于烟草N基因含LRR结构，上述3对引物比较适宜用于水稻稻瘟病抗性基因遗传背景分析。

关键词: 稻瘟病, 抗性表型, 抗性基因同源序列, 相似性