Assessment of Genetic Diversity in Corchorus olitorius Accessions by Simple Sequence Repeat Markers (SSR)

Abstract

Indigenous leafy vegetables such as Corchorus olitorius (jew’s mallow) have potential in contributing to food security as they can provide important nutritional requirements needed for human nourishment. However, in Botswana, this plant is not yet domesticated and its utilization is minimal due to lack of knowledge. To have the crop fully domesticated it is important to document important information on the available landraces and wild species. One of the important information is understanding the variation among the available genotypes as this will help not only in domestication but also in breeding purposes. Thus this study aimed to assess the genetic diversity of 49 accessions of jews mallow collected in Botswana and other African countries. Simple sequence repeats (SSR) markers were used to characterize fourty nine accessions. The results revealed that, out of 49 SSR primer pairs used, 46 showed scorable polymorphism by producing clear amplified products. The average polymorphic loci rate was 82.44% with the lowest rate (33.33%) detected in MJM-536 and the highest was 100% recorded by 27 of the primers. The polymorphism information content (PIC) potential ranged from 0.398 for MJM-475 primer to 0.979 for the primer MJM-623 with an average of 0.719. With the Shannon diversity index, an average of 3.626 was recorded under the studied accessions and this confirmed a very high diversity. In addition, a dendrogram was generated to illustrate the genetic diversity and possible relationships among the 49 Corchorus olitorius accessions using the unweighted pair group method (UPGM) with arithmetic means. This UPGM cluster analysis distinctively divided the accessions into five (5) groups at a cophenetic correlation coefficient 0.977. The total number of accessions per cluster varied from one group to the other. These results reinforced the effectiveness of the SSR markers in discriminating individuals within species even within a narrow genetic background.