Development and Application of Pi-kh Co-dominant Marker for Rice Blast Resistance Gene

Abstract

Rice, as one of the staple food crops in the world, is reduced by 10~30% every year due to the damage of rice blast. However, the application of marker assistant selection (MAS) with rice disease resistance genes can be effectively, accurately and rapidly used to breed rice blast resistant varieties. The rice blast resistance gene Pi-kh has been proved to have broad-spectrum resistance to the rice blast. Therefore, the selection and utilization of Pi-kh gene by MAS in rice disease resistance breeding possess high application value for improving rice blast resistance. In this study, based on two InDel differences in Coding sequence (CDS) region of Pi-kh gene, a co-dominant functional molecular marker was developed at the conservative position of the sequence, which was named ZJPikh. The marker was used in the disease resistance breeding with rice blast susceptible variety “Yudao 518” as female parent and rice blast resistant variety “Shida 68” as male parent. The genotype of gene Pi-kh related with rice blast resistance in F2 isolated population and high generation plants were verified by pedigree method and MAS. A new rice blast resistant third-grade variety “Yudao 58” with Pi-kh was successfully bred. At the same time, the Pi-kh genotypes of 21 main rice varieties were identified, which provided technical support for the targeted and efficient breeding of blast resistant varieties carrying Pi-kh gene through MAS technology. Our research provides convenience for identifying rice blast resistance germplasm resources and molecular marker-assisted disease resistance breeding.