Creating New Germplasm Of Rice Expressing Highly Resistant Bacterial Blight Gene By Somatic Hybridization

A bacterial blight (BB) resistance trait from a wild rice species, Oryza meyeriana (highly resistant to BB pathogens), was introduced into an elite japonica rice cultivar (Dalixiang) using asymmetric somatic hybridization. One hundred and thirty two independent hybrid lines were regenerated. The hybrid plants possessed several morphological features of O. meyeriana. Random Amplification of Polymorphic DNA (RAPD) analysis of ten of these hybrid lines revealed that hybrid plants exhibited some banding patterns derived from their parental genotypes. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. Majority of the hybrids showed intermediate resistance to BB pathogens between O. meyeriana and O. sativa (cv. Dalixiang). Six of the hybrid lines exhibited high BB resistance. These results demonstrates that O. meyeriana can be used a useful genetic source for breeding of BB resistance in commercial rice cultivars through asymmetric somatic hybridization, which serves as an alternative means to the transgenic approach.