Simple sequence repeat markers associated with anthracnose and Turcicum leaf blight resistance in sorghum

Abstract

Deployment of host resistance remains the most cost effective strategy for management of foliar and grain diseases, especially for resource constrained farmers. There is paucity of information on dual resistance in sorghum to both diseases. The objective of this study was to identify SSR markers associated with anthracnose and TLB resistance in sorghum for future use in markers assisted introgression. Mapping of resistance to anthracnose and Turcicum leaf blight (TLB) was undertaken in 126 F_8:9 sorghum recombinant inbred lines, derived from a cross between MUC007/009 and Epuripuri. The F_8:9 RILs were evaluated for field resistance to anthracnose and TLB in Uganda and Sudan. There were significant differences among locations (P<0.001), suggesting a strong influence of environments on reaction to both diseases. Transgressive segregation was observed, indicating that both parents carried minor loci or alleles for resistance that differed from each other. SSRs Xtxp25, Xtxp201, Xtxp302, Xtxp25, Xtxp295 and Xtxp95 were associated, respectively, with anthracnose and TLB resistance, consistent with dominant epistasis gene action. The SSRs Xtxp201 and Xtxp303 were associated with both anthracnose and TLB resistance. High polymorphic information content (0.44 to 0.59) and gene diversity (0.54 to 0.66) were observed. SSRs could be used to detect the dual resistant genotypes and, therefore, contribute substantive information to multiple disease resistance research of sorghum.

Keywords: Dual resistance, simple sequence repeats