Identification of new sources of bacterial blight ( Xanthomonas oryzae pv. oryzae ) resistance in wild Oryza species and O. glaberrima

Bacterial blight (BB) of rice is a widespread disease in tropical Asia, contained largely through the deployment of race-specific resistance genes. Although more than 25 BB resistance genes have been identified, none are effective individually against all the pathotypes prevalent in north-western India. The response of a set of 327 accessions of 13 wild Oryza species and cultivated African rice, O. glaberrima, was evaluated to infection with seven pathotypes of Xanthomonas oryzae pv. oryzae over a period of 3‐4 years. Of these, 67 were resistant or moderately resistant to all pathotypes. These comprised 13 accessions of O. glaberrima ,5o f O. barthii ,1 0 ofO. rufipogon ,4o fO. longistaminata ,2 2 ofO. nivara ,6o fO. officinalis ,2 of O. rhizomatis and 5 of O. minuta. Inheritance studies, molecular mapping and transfer of some of these genes into O. sativa ssp. indica are in progress.