Diversity and Population Structure of Local and Exotic Lablab Purpureus Accessions in Kenya as Revealed by Microsatellite Markers

Abstract

Lablab purpureus is an important pulse crop in some parts of sub-Saharan Africa and Asia but has largely remained underuti-lized. Understanding the genetic diversity is prerequisite for ge-netic improvement and utilization of this leguminous crop. The relationships of the local lablab genotypes and those collected from other diverse geographic origins including the wild acces-sions remain unknown in Kenya. The study was undertaken to determine genetic diversity and population structure of germ-plasm accessions collected from Kenya and other global regions. Eight simple sequence repeat primer pairs were used to genotype the 189 lablab accessions. A total of 39 alleles were re-vealed by eight SSR with an average of 4.88 alleles per polymor-phic loci. The average PIC was 0.42. The gene diversity among the accessions ranged from 0.26 to 0.52 with an average of 0.38, indicating moderate genetic diversity. Germplasm collected from Kenya showed a moderate genetic diversity of 0.36. Higher ge-netic diversity (He<0.5) was detected within the Ethiopian and South Africa populations. Analysis of molecular variance (AMO-VA) revealed that 94% of the allele diversity was attributed to in-dividuals within populations while only 6% was distributed among the populations. The Bayesian model-based Structure method and Principal coordinate analysis (PCoA) scatter plot clustered the accessions into three groups with germplasms collected from Kenya showing distribution among all the three groups. The wild accessions clustered mainly with those from Southern and Eastern Africa confirming earlier suggestions that lablab is of Af-rican origin. The results of this study are discussed in light of the crop improvement of this crop.