Marker assisted introgression of durable blast resistance gene pi-1 into popular Indica variety

Swarna is high yielding and widely grown indica rice cultivar covering a substantial portion of rice area in India and in the Asian countries such as Bangladesh, Philippines, Thailand and Indonesia, but it is highly susceptible to blast disease. The donor selected for the resistant gene is C101LAC carrying blast resistance gene Pi-1 derived from LAC23. The Pi-1 gene was done introgressed into Swarna by using Marker assisted backcross breeding method. Foreground selection was using RM224 linked marker to identify plants possessing resistance alleles in the segregating generations along with stringent phenotypic selection for faster recovery of the recurrent parent genome (RPG). Foreground selection coupled with stringent phenotypic selection identified plants homozygous for Pi-1, which was advanced to BC2F4 through pedigree selection. Marker-assisted selection for Pi-1 in BC2F4 using flanking markers identified five homozygous families. Background analysis with parental SSR markers was used to estimate the recovery of RPG in improved lines and it revealed that RPG recovery was up to 94.7% (# SL-10-3-7-63-45-7). Screening with highly virulent isolate SPI-28 showed that the improved lines were resistant to blast disease and were on a par with swarna for yield, and grain quality. These introgressed lines provide valuable material for resistant breeding program.