Genetics of Resistance in Rice Cultivars, Chugoku 45 and Java 14 to Philippine and Japanese Races of Bacterial Blight Pathogen

Abstract

Sateng, reported to have recessive gene xa9 for resistance to Xanthomonas campestris pv. oryzae, showed reactions similar to those of Chugoku 45, Java 14 and Zenith (all carrying the Xa3 resistance gene) in response to Japanese and Philippine races. Sateng was subjected to an allele test with the above cultivars. The reaction of F2 plants from the cross Toyonishiki (susceptible) X Sateng to Japanese race IIIA showed that Sateng has one dominant gene. All F2 plants of Chugoku 45 X Sateng and Sateng X Zenith were resistant, with browning around the lesions. The reaction of F1 and F2 populations from the cross of IR24 (susceptible) X Sateng and Toyonishiki X Sateng also showed that Sateng has one dominant gene for resistance to Philippine races 1 to 4. Lesion length of the F2 plants was variable, due to segregation of minor genes. The results indicated that Sateng had a dominant gene which is allelic to Xa3. Analysis of the F3 progenies from the cross Java 14 X Sateng using Philippine races confirmed these results.