Bacterial leaf blight (BB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) limits rice yield in all major rice-growing regions of the world. As the bacterial pathogen is difficult to manage, the development of host-plant resistance is considered the most effective and economical means to control BB. Twenty-four major genes conferring resistance to various races of the pathogen have been identified and used in rice breeding programs (Lee et al 2001). Several varieties with high or moderate resistance to BB have been released under the auspices of the All India Coordinated Rice Improvement Project (AICRIP). Variety Ajaya (IET8585), released in 1994 under AICRIP, is highly resistant to all pathotypes in India (DRR 1996).