Molecular Characterization of Spider Plant (Cleome gynandra) Accessions Using SSR Markers

Abstract

Spider plant (Cleome gynandra L.) is an indigenous leafy vegetable that is a rich source of minerals, proteins, vitamins, flavonoids, antioxidants and many other compounds. Morphological characterization of the germplasm for optimal genetic exploitation is limited by environmental factors. The objective of this study was to determine the degree of genetic diversity between exotic and local spider plant accessions using molecular markers. The spider plant germplasm consisted of 18 local and exotic accessions. Seven polymorphic simple sequence repeat (SSR) markers were used in the study. The SSR marker combinations revealed a total of 46 alleles at 7 loci, with an average of 6.57 alleles per locus. An average polymorphic information index of 0.69 was recorded. According to Nei’s genetic distance analysis, low population differentiation was observed between the local and exotic spider plant accessions, which was indicated by a low fixation index value of 0.024 and a high Nm (10.20). Analysis of molecular variance showed no significant (p < 0.327) variation among and within the local and exotic accessions. Furthermore, low population differentiation was recorded when accessions were grouped based on their stem colour, with an Fst value of 0.007. In both the hierarchical clustering using an unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCoA), the local accession ‘ML-3-KK’ was grouped alone, suggesting that this accession was different from the rest of the accessions and could be useful in selection programmes for spider plant genetic improvement. Both the UPGMA and PCoA were similar in clustering the eighteen spider plant accessions into four groups. The local spider plant accessions were more genetically diverse (with sixteen rare alleles) when compared to the exotic accessions (with only three rare alleles). The rare alleles provided useful information on the genetic variability in certain loci and identification of accessions that could be used as parental lines in spider plant breeding programmes.