Genetic diversity and population structure of Moringa oleifera

Moringa is a genus of the tropical flowering plant family Moringaceae containing 13 diverse species. Among the different species, only Moringa oleifera L. is cultivated. This species has great potential in serving as a high-value crop for food, medicinal products, as well as fodder for animals, particularly in developing tropical regions of the world. In this study, the genetic diversity and population structure of world-wide collections of M. oleifera were investigated using DNA markers. A total of 19 microsatellite or simple sequence repeat (SSR) markers along with a partial sequence of the chloroplast gene atpB were used to study genetic diversity within 161 accessions of M. oleifera collected from Asia, Africa, North and South America, and the Caribbean. On average, 8.3 alleles/per SSR were amplified in each accession. A total number of 158 alleles were detected in 131 accessions collected from the wild in Pakistan and from 30 accessions obtained from ECHO (Florida). Observed heterozygosity varied from 0.16 to 0.86, with an average of 0.58, while the average PIC value was 0.59. Partial sequencing of chloroplast genes of 43 of 161 plants generated mixed patterns. These findings have demonstrated that there is a large genetic diversity present in wild collections of M. oleifera collected in Pakistan; whereas low genetic diversity is detected in cultivated accessions obtained from ECHO. Taken together, these results agree with previous reports that M. oleifera is native to the Indo-Pakistan ecological region, and provides sufficient diversity for genetic exploration as well as for genetic improvement efforts.