Plant Genetic Resources: Characterization and Utilization

Research Article

Genetic diversity analysis of yam cultivars (Dioscorea rotundata Poir.) in Benin using simple sequence repeat (SSR) markers

Serge Tostaina1 c1, Clément Agbanglaa2, Nora Scarcellia1 p1, Cédric Mariaca1, Ogoubi Daïnoua2, Julien Berthauda1 and Jean-Louis Phama1

a1 Institut de Recherche pour le Développement (IRD), UMR 1097: Diversité et Génomes des Plantes Cultivées, Equipe Dynadiv, BP 64501, F-34394 Montpellier cedex 5, France

a2 Laboratoire de Génétique, Faculté des Sciences et Techniques de l'Université d'Abomey Calavi, 01BP 526 Cotonou, République du Bénin


Guinea yam (Dioscorea rotundata Poir.) is a dioecious vegetatively propagated tuber crop. It is widely cultivated by traditional techniques in West Africa, its area of origin. The genetic diversity of 146 accessions from Benin was analysed using 10 polymorphic simple sequence repeat (SSR) nuclear markers and agromorphological traits. An average of 8.4 alleles per locus was detected. The mean heterozygosity was 0.57 and the mean polymorphism information content (PIC) for polymorphic markers was 0.51. Some cultivars (23%) were found to have an identical genotype for the 10 markers. The structure of the genetic diversity observed in Benin is the result of farmers' crop management practices and their know-how. The cultivar diversity had a geographical component. We also noted major differentiation between early and late cultivars, with higher diversity in the early ones. Cultivars from northern Benin and early cultivars had the greatest allelic richness. SSR markers proved to be powerful tools for fingerprinting each cultivar and analysing their genetic relationships. The results of this study could be useful for defining a strategy for the conservation of genetic diversity in yams.

(Received January 30 2006)

(Accepted September 18 2006)