Inheritance of blast resistance in three Indica rice cultivars

Three Indica rice cultivars Tetep, Ta-Poo-Cho-Z and Pankhari 203, which were resistant to the blast fungus Pyricularia oryzae, were crossed to a susceptible Korean rice cultivar Tongil. The resistant Indica rice cultivars were crossed each other for allelism test. The F₂s were screened against four races IA-61, IB-47, IC-27 and IH-1. Inheritance pattern, relationships between reactions to different races in the same F₂ plants, and allelism relationships were studied. The rice cultivar Tetep was found to convey three dominant resistance genes, Ta-Poo-Cho-Z one dominant and one recessive resistance genes, and Pankhari 203 one dominant resistance gene against those fungus races tested. The resistance gene of Pankhari 203 was common to one of the three resistance genes of Tetep. Thus, five reistance genes to blast fungus were found; three dominant genes from Tetep, one dominant and one recessive genes from Ta-Poo-Cho-Z.