Field screening for blast resistance gene donors, among rice mutant lines of Mira-1

Abstract

Rice blast disease, caused by Pyricularia grisea was one of the most destructive fungal diseases in rice worldwide. Therefore, resistance breeding requires continuous efforts to enrich the reservoir of resistance rice lines to effectively tackle the disease. Mutation induction of the Mira-1 rice variety by gamma rays has been conducted, and M6 generation of rice mutant lines was used for this experiment. The rice mutant lines were selected from a total 112 number of rice mutant lines and it had been planted at Cikembar, Sukabumi Village. Cikembar is a hot spot area of blast disease which was used by researchers for the identification of rice lines resistant to blast, and plants were naturally infected. Disease progress was recorded as leaf and neck blast from 0 to 9 ( highly resistant to highly susceptible ). The results showed that disease severity was significantly different in the rice mutant lines studied and it was consistent and not affected by the plant arrangement in the field. Five rice mutant lines showed high resistance to blast disease, and it found 25 numbers of rice mutant lines scored 1 or resistant to blast disease, meanwhile, their wild type of Mira-1 rice variety showed susceptibility to leaf blast and neck blast diseases respectively. The agronomic traits of rice mutant lines were better than their wild type of Mira-1 rice variety. It was found that Mi-37, Mi-77, the Mi-82 rice mutant lines were the best lines for the gene donors of rice-resistant mutant line.