Genetic Diversity and Population Structure Analysis of Hoary Basil ( Ocimum americanum L.) Germplasm From Burkina Faso Using Simple Sequence Repeat (SSR) Markers

Ocimum americanum is a wild, aromatic species belonging to the Lamiaceae family. It holds significant socioeconomic importance as it is widely utilized in agriculture, medicine, and food by the local population in Burkina Faso. Previous works revealed that O. americanum is one of the candidate species for domestication in Burkina Faso. Such a perspective requires a good understanding of its genetic diversity. This study was carried out to assess the genetic diversity of O. americanum based on simple sequence repeat (SSR) markers, also known as microsatellites. To achieve this goal, 79 accessions of O. americanum collected in three phytogeographic sectors (sub-Sahelian, North Sudanian, and South Sudanian) were genotyped using 13 SSR markers. Nine SSR markers out of 13 revealed polymorphism within the accessions with PIC values ranging between 0.047 and 0.443. In all, 36 alleles were identified and the expected heterozygosity ranged from 0.047 to 0.449. Significant differences were observed between the accessions based on the phytogeographic sectors of origin. The analysis of the organization of the genetic diversity using the STRUCTURE approach led to two genetic groups, while the discriminant analysis of principal components (DAPC) revealed six groups. This study is the first report on the genetic diversity of O. americanum in Burkina Faso. The results of this study could help in developing a strategy for the sustainable management and utilization of the genetic resources of hoary basil.