Association mapping of traits related to leaf blast disease in rice (Oryza sativa L.)

The present research was conducted to validate and verify the association of SSR markers with traits related to leaf blast disease in 121 rice cultivars. Number of spots, number of spore-producing spots, spot size, infection type, infection percentage, and the area under the disease progress curve (AUDPC) were the blast-related traits measured in the rice blast nursery. Evaluation of genetic diversity of markers indicated that RM166 had the highest level of diversity indices including observed number of alleles, effective number of alleles, polymorphism information content (PIC) value, gene diversity, and Shannon’s index. Thus, RM166 is the more valuable marker which can be used in association mapping because of the high opportunity of linkage to valuable disease resistance traits. Association mapping was performed using population structure matrix through the general linear model (GLM) and the mixed linear model (MLM). Based on a structure analysis, three subpopulations were observed in the rice population of this study. Among the set of selected markers, 30 and 29 markers exhibited a significant linkage with traits related to blast disease in GLM and MLM, respectively. RM224 had the most significant relationship with evaluated traits in both GLM and MLM, suggesting that this marker can be used in breeding programs.