A genetic diversity analysis of South African sorghum genotypes using SSR markers

Abstract

Diverse landraces of sorghum (Sorghum bicolor (L.) Moench) are widely grown by smallholder farmers in South Africa. The objective of the study was to assess the genetic diversity present in South African sorghum genotypes using genetic distances as measured by simple sequence repeat (SSR) markers. In total 103 diverse landraces and breeding lines were genotyped using 30 SSR primers. A wide genetic diversity was observed with the allele sizes ranging from 90 to 294 bp. The numbers of alleles ranged from 2 to 15 with an average of 6.4 per locus. The polymorphic information content ranged from 0.0192 to 0.8351 (average 0.5031) with heterozygosity values of 0.0194 to 0.8524 (average 0.5483). The Euclidian genetic distances varied from 0 to 8.4 (average 5.7). Genotypes Macia-SA and AS4 had the lowest dissimilarity index, whereas 05-POTCH-115 and MP2048 exhibited the highest value. The study established the existence of considerable genetic diversity among South African sorghum germplasm. This may enable breeders to exploit the potential of transgressive segregation and for strategic genetic conservation.