Abstract
Inheritance of resistance to a genetically-characterised, representative pathotype of Xanthomonas oryzae (Ishiyama) pv. oryzae was studied in three multiple insect-pest and bacterial blight (BB) resistant rice lines, namely, R650-1817, TTB148-174-3-2-1, and TTB148-206-1-1-1. Segregation patterns in the F1, F2, and F3 populations derived from crosses between these lines and a highly susceptible cultivar, Taichung (Native) 1 (TN1), revealed that a single dominant gene controlled resistance to BB in each of the three rice lines. Disease reaction of the F2 populations of intercrosses among the three lines indicated that the dominant gene controlling resistance in TTB174-3-2-1 and TTB148-206-1-1-1 was the same (allelic). However, the dominant gene controlling BB resistance in R650-1817 was non-allelic to the dominant gene of TTB174-3-2-1 as well as TTB148-206-1-1-1.