Identification of allelic genes conferring resistance to Xanthomonas campestris pv. Oryzae in eight cultivars of rice

Rice cultivars Ruchi, RM 1, R 435–107, R 435–756, IR 54, RP 2151-40-1, BG 400-1 and DV 85 were genetically analysed against the Indian pathotype group I of bacterial blight. The varieties were crossed with the susceptible T(N)1 and amongst themselves. The F_l and F₂ analyses clarified that the cl1ltivars possessed one recessive gene for resistance. These genes for resistance can be grouped in to three allelic groups. Group 1-Ruchi and BG 400-1, Group.2 RP 2151-40-1, DV 85 and RM 1 and Group-3 IR 54, R 435–107, R 435–756.