Abstract:

【Objective】 Comparison of resistance spectrums with known BB resistance genes and genetic analysis revealed that the rice germplasm C4059 harbored a new BB resistance gene, designated tentatively as Xa36 (t). Molecular mapping of Xa36 (t) gene and breeding of its near-isogenic line were made by constructing populations with a susceptible indica variety IR24 as recurrent parent.【Method】 A F3 population was used for molecular mapping of Xa36 (t). Bulked Segregant Analysis (BSA) was adopted to survey SSR and EST molecular markers. 【Result】 Thirteen markers on rice chromosome 11 displayed polymorphism between the S-pool and R-pool. The four molecular markers, RM2136, RM7443, RM1233, and RM224, were the nearest markers to Xa36 (t). Linkage analysis revealed that RM2136 and RM7443 were located near the telomere of the chromosome, with genetic distances of 3.2 and 3.8 cM to the resistance gene, respectively, while RM1233 and RM224 were located on the other side of Xa36 (t), with genetic distances of 1.9 and 1.3 cM, respectively. 【Conclusion】 By analyzing the F3 populations, the gene Xa36 (t) was mapped within a length of 4.5 cM on the long arm of rice chromosome 11.

Key words: rice bacterial blight, Xa36(t), gene mapping