Analysis of Rice Blast Resistance Dominant Genes and their Combinations in Japonica Rice

AbstractRice blast is a disastrous fungal disease affecting rice (Oryza sativa L.) and undermines world food security. Different ecological conditions and genetic backgrounds altered the effectiveness of rice blast resistance genes. Anhui (China) is a high‐incidence area and has long been affected by rice blast. Despite chemical or other control methods of rice blast, analyzing the effects of specific rice blast resistance genes within the Anhui region, identifying favorable genes (combinations), and incorporating them into the process of new variety selection and breeding programs are effective ways to improve rice blast resistance. This research study examined the distribution of 16 rice blast resistance genes (i.e., Pi‐ta, Pi5, Pi1, Pia, etc.) in a recombinant self‐cross population of japonica rice and analyzed their correlation to panicle neck blast resistance. Five genes, Pit, Pi‐ta, Pik, Pb1, and Pi54, were identified and evaluated as dominant genes to improve panicle neck blast resistance. Further comparisons of the neck blast resistance levels between various gene combinations revealed that Pi54, when combined with Pb1/Pi‐ta (Pi54 + Pb1, Pi54 + Pi‐ta), could further increase resistance to panicle neck blast; and the highest resistance level was found with the three‐gene combination of Pi54 + Pi‐ta + Pb1. Meanwhile, the neck blast resistance capacity of Pi54 and Pb1 was significantly improved after polymerization with Pit and Pik (Pik + Pi54, Pit + Pi54, Pit + Pb1). Therefore, gene polymerization is widely regarded as a successful strategy to breed varieties with long‐lasting and broad‐spectrum resistance. It is anticipated that rice blast tolerance capacity will be considerably improved by gene polymerization of dominant genes.