Transferring striga resistance Qtl from a resistant donor source into in Rwandan adapted sorghum variety

Abstract

Sorghum [Sorghum bicolor (L.) Moench] is one of the most important cereal crops globally after wheat, maize, rice, and barley and has an important role in the food and fodder security for millions of rural families in arid and semi-arid regions of the world. Despite its important role, sorghum is affected by numerous pests, weeds and diseases such Striga sp, stalk and root rot diseases, leaf blights, downy mildews, virus diseases, smuts, rust, greenbugs, sorghum midge, stem and stalk borers, shoot fly, and others. Among these constraints, Striga hermonthica is a major biotic constraint to sorghum production in the Eastern region of Rwanda. In this study, a molecular marker assisted introgression of five Striga resistance QTL from a resistant donor N13 line located on SBI-Ol, SBI-02, SBI-05 (with 2QTL) and SBI-06 was performed to improve IS8193 line, a farmer preferred variety in the Eastern region of the country. The transfer of these QTL was confirmed with the help of Simple Sequences Repeats (SSRs) molecular markers. Nine foreground polymorphic SSR markers were used to identify F, and BC,F, progenies carrying Striga resistance QTL. From a cross between IS8193 and N13, twenty F, progenies were genotyped. Sixteen of these were found to be heterozygous, with one to three Striga resistance QTL. The sixteen selected genotypes were back-crossed to IS8193 to produce BC,F, generation. After BC,F, progenies genotyping, twelve BC,F, lines were identified to carry one to three Striga resistance QTL and were again backcrossed to IS8193 to produce BC2F, genotypes. The study showed a successful introgression of Striga resistance QTL into Rwanda material and the BC2F, lines carrying Striga resistance QTL will assist in further generations to produce a ready resistant variety, although it will require further backcrossing and genotyping.