Genetic Structure and Diversity of Rice From Certified Cultivars and Farmer’s Fields in Burkina Faso

Background: In West Africa, two rice species are cultivated, the African rice Oryza glaberrima and the Asian rice Oryza sativa, the second one being much more frequent. Despite its importance for food security in West Africa, the genetic diversity of Oryza sativa in farmer’s fields remains understudied in this region. Documenting the dynamics of diversity in the fields between landraces and improved cultivars is of importance to ensure rice cultivation adaptation to global change.In this study, we genotyped 77 rice samples from Burkina Faso using the C6AIR SNP array from IRRI. Among the studied samples, 27 were certified cultivars and 50 were sampled in rice fields from three geographical zones in western Burkina Faso, each zone comprising one irrigated area and a neighboring rainfed lowland. Obtained data were analyzed in the frame of the worldwide rice genetic diversity by using the 3K genomes as reference.Results: Most of the certified cultivars clustered with the indica genetic group, with a minority (26%) assigned to the japonica group. All except one of the rice samples from farmer’s fields belonged to the indica group. The peculiar one unexpectedly clustered with the Aus genetic group and originated from Tengrela (rainfed lowland in Karfiguela zone). This site, already known to differ in terms of agronomic practices, showed the highest genetic diversity compared to the five other sites, as well as highest genetic differentiation. Obtained genetic data confirmed the high global frequency of one cultivar, in accordance with the data from farmer’s interview. However, at the field level, genetic data rarely corresponded to the cultivar’s names obtained from farmer’s interviews.Conclusions: Overall we found a high genetic diversity in the studied samples from Burkina Faso (certified and field’s samples). We argue on the importance to document and preserve this agro-biodiversity as a prerequisite to face the current challenges of growing rice demand and global change. To this purpose, are required further scientific studies to refine our understanding of the dynamics of diversity in farmers’ fields, as well as a better knowledge of rice agro-biodiversity and awareness of its importance by rice farmers themselves.