| dc.description.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. | en |
