多基因聚合培育抗稻瘟病且镉低积累水稻新种质OA

This study aimed to breed new rice germplasm with rice blast resistance and low cadmium accumulation in grains.The two-line sterile rice line Zhi 796S carrying the rice blast resistance gene Pita,the maintainer line Jinzhen B,the restorer line Zhixianghui 859 carrying Pi2,and the intermediate material KZ-3425 of the restorer line that carried the rice blast resistance gene were used as receptor parents.Luohong 4B and Xiang'an 1 with OsNramp5 deletion were used as the donor parents.Molecular marker-assisted selection was used to integrate the rice blast resistance gene(Pita/Pi2)and the allele of low cadmium accumulation gene OsNramp5 deletion into the same genetic background through crossing,back-crossing,and multi-generation selfing.The results showed that the obtained rice line carrying Pi2 exhibited moderate resistance(grade 3)to rice blast,which was significantly higher than that(moderate susceptibility,grade 5)of the receptor parent.The obtained lines showed the cadmium content within the range of 0.011-0.035 mg/kg,which was far below the limit of 0.2 mg/kg specified in the national food safety standard.There were significant differences in the agronomic traits of improved lines with different genetic backgrounds.The lines LF104,LF106,and LF107 with the genetic background of Zhixianghui 859 demonstrated excellent comprehensive traits and possessed moderate resistance to rice blast and low cadmium accumulation in grains.This study provided a material basis and theoretical reference for green and safe rice production in cadmium-contaminated areas.