title: Genetic diversity and population structure of castor (Ricinus communis L.) germplasm within the US collection assessed with EST-SSR markers.
abstract: Castor is an important oilseed crop and although its oil is inedible, it has multiple industrial and pharmaceutical applications. The entire US castor germplasm collection was previously screened for oil content and fatty acid composition, but its genetic diversity and population structure has not been determined. Based on the screening results of oil content, fatty acid composition, and country origins, 574 accessions were selected and genotyped with 22 polymorphic EST-SSR markers. The results from cluster analysis, population structure, and principal component analysis were consistent, and partitioned accessions into four subpopulations. Although there were certain levels of admixtures among groups, these clusters and subpopulations aligned with geographic origins. Both divergent and redundant accessions were identified in this study. The US castor germplasm collection encompasses a moderately high level of genetic diversity (pairwise dissimilarity coefficient = 0.53). The results obtained here will be useful for choosing accessions as parents to make crosses in breeding programs and prioritizing accessions for regeneration to improve germplasm management. A subset of 230 accessions was selected and will be planted in the field for establishing a core collection of the US castor germplasm. Further evaluation of the US castor germplasm collection is also discussed.
authors.affiliation: a USDA-ARS, Plant Genetic Resources Conservation Unit, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Wang
authors.affiliation: b Department of Agronomy, Iowa State University, 2014 Agronomy Hall, Ames, IA 50011, USA.
authors.forename: M
authors.initials: M
authors.lastname: Dzievit
authors.affiliation: c Department of Crop and Soil Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.affiliation: a USDA-ARS, Plant Genetic Resources Conservation Unit, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Morris
authors.affiliation: d Emory University Hospital, Emory University, 1364 Clifton Road, Atlanta, GA 30322, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Norris
authors.affiliation: a USDA-ARS, Plant Genetic Resources Conservation Unit, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Barkley
authors.affiliation: a USDA-ARS, Plant Genetic Resources Conservation Unit, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: B
authors.initials: B
authors.lastname: Tonnis
authors.affiliation: a USDA-ARS, Plant Genetic Resources Conservation Unit, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Pederson
authors.affiliation: b Department of Agronomy, Iowa State University, 2014 Agronomy Hall, Ames, IA 50011, USA.
authors.forename: J
authors.initials: J
authors.lastname: Yu
mesh_terms: D000483:Alleles; D016000:Cluster Analysis; D020224:Expressed Sequence Tags; D005227:Fatty Acids / Q000737:chemistry; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D005843:Geography; D018895:Microsatellite Repeats; D011110:Polymorphism, Genetic; D025341:Principal Component Analysis; D012276:Ricin / Q000235:genetics; D012278:Ricinus / Q000235:genetics*; D014481:United States
chemical_list: D005227:Fatty Acids; D005819:Genetic Markers; D012276:Ricin
keywords: EST-SSR marker; castor germplasm; core collection establishment; diversité génétique; genetic diversity; germoplasme de ricin; marqueur EST-SSR; population structure; structure de population; établissement d’une collection nucléaire