agronomy Article Genotyping-by-Sequencing to Unlock Genetic Diversity and Population Structure in White Yam (Dioscorea rotundata Poir.) Ranjana Bhattacharjee 1,* , Paterne Agre 1 , Guillaume Bauchet 2, David De Koeyer 3, Antonio Lopez-Montes 1,4, P. Lava Kumar 1 , Michael Abberton 1, Patrick Adebola 5, Asrat Asfaw 5 and Robert Asiedu 1 1 International Institute of Tropical Agriculture, PMB 5320, Ibadan 200001, Nigeria;
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[email protected] Received: 7 August 2020; Accepted: 14 September 2020; Published: 22 September 2020 Abstract: White yam (Dioscorea rotundata Poir.) is one of the most important tuber crops in West Africa, where it is indigenous and represents the largest repository of biodiversity through several years of domestication, production, consumption, and trade. In this study, the genotyping-by-sequencing (GBS) approach was used to sequence 814 genotypes consisting of genebank landraces, breeding lines, and market varieties to understand the level of genetic diversity and pattern of the population structure among them. The genetic diversity among different genotypes was assessed using three complementary clustering methods, the model-based admixture, discriminant analysis of principal components (DAPC), and phylogenetic tree.