Genetic diversity among sorghum landraces and polymorphism assessment of local improved varieties for stay-green trait

Abstract

Microsatellites or simple sequence repeats (SSR) are playing an important role in molecular breeding. This investigation was undertaken to study the genetic diversity among local sorghum accessions from two different agro-ecological zones of Burkina Faso and to assess the polymorphism within local improved varieties and a source (B35) exhibiting the stay-green trait. One hundred and eighty-six local and some exotic accessions were assessed using 26 SSR markers (including 14 markers linked to stay-green QTLs). DNA was extracted using Mixed Alkyl Trimethyl Ammonium Bromide method from dried sample after collection of leaves from three week old plantlets. The average number of alleles per locus was 4 with a medium value of gene diversity (He=0.45) across loci, indicating a low level of dissimilarity among local accessions. The genetic differentiation was significant between local and exotic materials and accessions were grouped according to their racial affiliation. The important finding was the presence of private alleles at markers linked to stay-green loci in the background of some local guinea accessions. The polymorphism between B35 and some local improved varieties for stay-green QTL indicates that most of the linked markers could be used in a breeding program through marker-assisted selection. Keywords : Sorghum, diversity, stay-green trait, marker, polymorphism.