Inheritance of resistance to bacterial Blight in ten rice (Oryza sativa L.) cultivars

Abstract

Ten rice cultivars from the International Rice Germplasm Centre originating from Bangladesh were analysed for their genetics of resistance to bacterial blight. The test cultivars were selected on the basis of their high level of resistance to races IV & VI of Xanthomonas oryzae pv. oryzae. The mode of inheritance was studied by crossing the test cultivars with Taichung Native 1 (TNI) which is highly susceptible to the races 1,2,3;4 & 6 of X. Oryzae pv. oryzae. The genetic analysis revealed that the test cultivars have two recessive genes conferring resistance to races 1 (PX 061) and 6 (PX 079) of X. oryzae pv oryzae, respectively. The allelic relationship of genes conferring resistance with xa-5 and xa-13 was oryzae, respectively. The allelic relationship of genes conferring resistance with xa-S and xa-13 was studied in progenies derived from crosses between the cultivars and IRBB5 and IRBB13 which are near isogenic lines carrying genes xa-5 and xa-13 respectively. The Chi-square analysis of F₂ populations revealed that resistance in these cultivars to race 1 was conferred by xa-5. Resistance to race 6 was found by xa-5. Resistance to race 6 was found.

Keywords: Oryza sativa, rice, Xanthomonas oryzae pv. oryzae, bacterial blight, races

Tanzania J. Agric. Sc. (2000) Vol. 3 No.1, 39-46