Genetic diversity of Sorghum bicolor (L.) Moench landraces from Northwestern Benin as revealed by microsatellite markers

The understanding of genetic diversity within local crop varieties constitutes an important step in the preservation of their genetic potential. The objective of this study was to assess the genetic diversity of sorghum (Sorghum bicolor (L.) Moench) cultivated in the Northwest of Benin and to reveal certain fundamental evolutionary mechanisms. A total of 61 accessions of sorghum landraces belonging to the four identified races in Benin were estimated using 20 microsatellite markers. For all the loci analyzed, 140 polymorphic alleles were detected with a mean value of 7.00 per locus and polymorphic information content (PIC) average value was 0.33 for all the 20 simple sequence repeats (SSRs), suggesting an important genetic diversity within the cultivated sorghum germplasm used. An unweighted pair group method arithmetic average (UPGMA) clustering and principal coordinate analysis (PCoA) based on DICE coefficient revealed three major genetic groups supported by two main components: the botanical race and the morpho-physiological characteristics of the grains (colour and degree of bitterness). It was thus recommended that further research on genetic diversity of sorghum should integrate these genetic parameters for a better preservation of the genetic resources of this important crop in Benin.Keywords: Genetic diversity, simple sequence repeats (SSRs) markers, Sorghum bicolor, Benin.