Introgression of Pi-kh Resistance Gene into a Malaysian Cultivar, MR264 using Marker-Assisted Backcrossing (MABC)

Magnophorthe oryzae is one of the most destructive disease that affected rice productivity. Developing new breeding strategies for durable blast resistant varieties is essential for crop protection. In this study, we aimed to introgress a blast resistance gene using local resistant genotypes, Pongsu Seribu 2 into MR264, a high-yielding rice variety that is blast susceptible thru Marker-Assisted Backcrossing (MABC) approach. Results demonstrated that, resistance gene (Pi-kh) was successfully incorporated into MR264-rice variety. Two foreground markers, RM206 and RM5961 were identified tightly linked to the target gene which located at chromosome 11. Both markers were utilized at each backcrossed generation to identify plants possessing heterozygous alleles for the target gene. A total of 82 background markers were used to evaluate recovery of recurrent parent genome in each backcrossed generation. The percentage of recovery of parent genome in BC1F1 and BC2F1 were 79.1% and 89.7% indicated a higher percentage compared to conventional method. The expected number of resistant and susceptible plants in segregation ratio for a backcrossed model fitted with 1:1 with (pgreater than 0.05) was not significantly different form the number of observed plants. This research finding will be helpful guidance of application of MABC in developing a blast resistant variety with highest recovery of RP genome with reducing number of generation.