Analysis of blast resistance genes and panicle neck blast resistances of conventional indica rice varieties

Objective To indentify the blast resistance genes and resistance effects of conventional indica rice variety resources.

Method The distribution of 14 blast resistance genes in 121 conventional indica rice varieties were genotyped using PARMS SNP typing technology. Natural identification of panicle neck blast was conducted in the field, and the relationship between genotype and resistance was analyzed.

Result Most of the tested varieties carried 2−6 blast resistance genes. The detection rates of Pi46 and Pia were 3.3% and 7.4%, respectively. The detection rates of Pi54 and Pi5 were 86.0% and 67.8%, respectively. None of the tested varieties carried Pi9, Pigm, Pik-m, or Pik. Field resistance identification showed the resistances to panicle neck blast of the tested varieties were generally weak, yet the resistances of Guangdong varieties were significantly higher than those of Guangxi varieties. There was no significant correlation between the number of resistance genes and the resistance to panicle neck blast. Pi2 and Pid3 had significant contributions on the resistance to panicle neck blast, with the odds ratios of 5.98 and 7.50, respectively. The combinations of Pi2⁺Pid3⁺, Pi2⁺Pi33⁺ and Pid3⁺Pi33⁺ showed higher resistance to panicle neck blast.

Conclusion The results of this study provides a theoretical support for the parent selection of pyramiding breeding using rice blast resistance genes in the indica rice regions of Guangdong and Guangxi, and provides scientific references for the rational layout of conventional rice.