Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major seed-borne pathogen of rice and is a threat to rice production in both temperate and tropical rice-growing regions, due to its high epidemic potential (Mew, 1987). BLB of rice causes considerable losses in all cultivars of rice in India, particularly in the Punjab state of India