Genetics of resistance in rice cultivar Sateng to Philippine and Japanese races of bacterial blight pathogen

Abstract

Rice cultivar Sateng was analyzed for resistance to bacterial blight of rice (BB) caused by Xaeathomonas campestris pv. oryzae, using Japanese and Philippine BB races. Sateng had been reported to have a recessive gene, xa-9. However, it showed reactions similar to those of Chugoku 45, Java 14, and Zenith against Japanese and Philippine races in our preliminary experiment. Therefore, Sateng was subjected to an allele test with the above cultivars which have Xa-3 gene, using Japanese and Philippine races. The reaction of the F₂ population from the cross Toyonishiki/Sateng to Japanese race IIIA showed that Sateng has one domlnant gene. All F₂ plants of Chugoku 45/Sateng and Sateng/Zenith were resistant with browning around the lesions. The reaction of F₁ and F₂ populations from the cross of IR24/Sateng and Toyonishiki/Sateng also showed that Sateng has one dominant gene for resistance to Philippine races 1 to 4. Lesion length of the F₂ plants was somewhat variable due to segregation of minor genes. These results indicated that Sateng has a dominant gene which is allelic to Xa-3. Analyis of the F₃ progenies from the cross Java 14/Sateng using Philippine races confirmed these results.