title: Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers.
abstract: Yams (Dioscorea sp.) are staple food crops for millions of people in tropical and subtropical regions. Dioscorea alata, also known as greater yam, is one of the major cultivated species and most widely distributed throughout the tropics. Despite its economic and cultural importance, very little is known about its origin, diversity and genetics. As a consequence, breeding efforts for resistance to its main disease, anthracnose, have been fairly limited. The objective of this study was to contribute to the understanding of D. alata genetic diversity by genotyping 384 accessions from different geographical regions (South Pacific, Asia, Africa and the Caribbean), using 24 microsatellite markers. Diversity structuration was assessed via Principal Coordinate Analysis, UPGMA analysis and the Bayesian approach implemented in STRUCTURE. Our results revealed the existence of a wide genetic diversity and a significant structuring associated with geographic origin, ploidy levels and morpho-agronomic characteristics. Seventeen major groups of genetically close cultivars have been identified, including eleven groups of diploid cultivars, four groups of triploids and two groups of tetraploids. STRUCTURE revealed the existence of six populations in the diploid genetic pool and a few admixed cultivars. These results will be very useful for rationalizing D. alata genetic resources in breeding programs across different regions and for improving germplasm conservation methods.
authors.affiliation: Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), Centre de Coopération International en Recherche Agronomique pour le Développement (CIRAD), Station de Roujol, Petit Bourg, Guadeloupe, France.
authors.forename: Gemma
authors.initials: G
authors.lastname: Arnau
authors.affiliation: Bioscience Center, International Institute of Tropical Agriculture (IITA), PMB, Ibadan, Oyo State, Nigeria.
authors.forename: Ranjana
authors.identifier: http://orcid.org/0000-0002-5184-5930
authors.initials: R
authors.lastname: Bhattacharjee
authors.affiliation: Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Triruvananthapuram, India.
authors.forename: Sheela
authors.initials: S
authors.lastname: Mn
authors.affiliation: Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Montpellier, France.
authors.forename: Hana
authors.initials: H
authors.lastname: Chair
authors.affiliation: Vanuatu Agricultural Research and Technical Centre (VARTC), Espiritu Santo PB, Vanuatu.
authors.forename: Roger
authors.initials: R
authors.lastname: Malapa
authors.affiliation: Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Port-Vila, Vanuatu.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lebot
authors.affiliation: Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Triruvananthapuram, India.
authors.forename: Abraham
authors.initials: A
authors.lastname: K
authors.affiliation: Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes (UMR Agap), CIRAD, Montpellier, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Perrier
authors.affiliation: ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France.
authors.forename: Dalila
authors.initials: D
authors.lastname: Petro
authors.affiliation: ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Penet
authors.affiliation: ASTRO Agrosystèmes Tropicaux, INRA, Petit-Bourg (Guadeloupe), France.
authors.forename: Claudie
authors.initials: C
authors.lastname: Pavis
mesh_terms: D000349:Africa; D001208:Asia; D001499:Bayes Theorem; D017691:Caribbean Region; D020231:Colletotrichum / Q000472:pathogenicity / Q000502:physiology*; D018556:Crops, Agricultural; D027742:Dioscorea / Q000145:classification / Q000235:genetics* / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics*; D005819:Genetic Markers; D014644:Genetic Variation; D018895:Microsatellite Repeats; D010802:Phylogeny; D058974:Phylogeography; D000069600:Plant Breeding; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D011003:Ploidies; D025341:Principal Component Analysis
chemical_list: D005819:Genetic Markers