Abstract: The homologues of 24 rice cultivars were analyzed using 19 candidate resistance gene (CRG) probes from rice and barley with NBS-LRR structure, while the resistance of the cultivars was tested by inoculating 26 isolates of Magnaporthe grisea in this study. The results showed that the 24 cultivars had 127 loci totally, each probe had 6.7 loci averagely. Except for Qitougu, Babaogu and Zinuo, indica cultivars had more loci and higher blast resistance than japonica ones in field and artificial inoculation, implying the positive correlation between the DNA band numbers and blast resistance. The clustering analysis classified the 24 cultivars into 2 groups and 5 subgroups, which respectively corresponded to indica-japonica differentiation and known rice heterotic groups based on pedigree information and blast reaction. The results demonstrated that CRG markers could be used to investigate genetic relationships among rice cultivars, and to control rice blast by inter-planting different cultivars and thus providing rice resistance breeding with parent genetic background.

Key words: Rice (Oryza sativa L.), Candidate resistance gene, RFLP, Diversity, Rice blast