title: Genetic architecture of kernel composition in global sorghum germplasm.
abstract: Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for dryland areas in the United States and for small-holder farmers in Africa. Natural variation of sorghum grain composition (protein, fat, and starch) between accessions can be used for crop improvement, but the genetic controls are still unresolved. The goals of this study were to quantify natural variation of sorghum grain composition and to identify single-nucleotide polymorphisms (SNPs) associated with variation in grain composition concentrations.
  
  
  
  In this study, we quantified protein, fat, and starch in a global sorghum diversity panel using near-infrared spectroscopy (NIRS). Protein content ranged from 8.1 to 18.8%, fat content ranged from 1.0 to 4.3%, and starch content ranged from 61.7 to 71.1%. Durra and bicolor-durra sorghum from Ethiopia and India had the highest protein and fat and the lowest starch content, while kafir sorghum from USA, India, and South Africa had the lowest protein and the highest starch content. Genome-wide association studies (GWAS) identified quantitative trait loci (QTL) for sorghum protein, fat, and starch. Previously published RNAseq data was used to identify candidate genes within a GWAS QTL region. A putative alpha-amylase 3 gene, which has previously been shown to be associated with grain composition traits, was identified as a strong candidate for protein and fat variation.
  
  
  
  We identified promising sources of genetic material for manipulation of grain composition traits, and several loci and candidate genes that may control sorghum grain composition. This survey of grain composition in sorghum germplasm and identification of protein, fat, and starch QTL contributes to our understanding of the genetic basis of natural variation in sorghum grain nutritional traits.
authors.affiliation: Center for Grain and Animal Health Research, USDA-ARS, 1515 College Ave, Manhattan, Kansas, 66502, USA. davina.rhodes@ars.usda.gov.
authors.forename: Davina H
authors.initials: DH
authors.lastname: Rhodes
authors.affiliation: Department of Soil & Crop Sciences, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: Leo
authors.initials: L
authors.lastname: Hoffmann
authors.affiliation: Department of Soil & Crop Sciences, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Rooney
authors.affiliation: Center for Grain and Animal Health Research, USDA-ARS, 1515 College Ave, Manhattan, Kansas, 66502, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Herald
authors.affiliation: Center for Grain and Animal Health Research, USDA-ARS, 1515 College Ave, Manhattan, Kansas, 66502, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Bean
authors.affiliation: Institute of Translational Genomics, Clemson University, Clemson, SC, 29634, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Boyles
authors.affiliation: Institute of Translational Genomics, Clemson University, Clemson, SC, 29634, USA.
authors.forename: Zachary W
authors.initials: ZW
authors.lastname: Brenton
authors.affiliation: Institute of Translational Genomics, Clemson University, Clemson, SC, 29634, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kresovich
mesh_terms: D002523:Edible Grain / Q000737:chemistry / Q000235:genetics; D056726:Genetic Association Studies; D055106:Genome-Wide Association Study; D023281:Genomics / Q000379:methods; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000737:chemistry* / Q000235:genetics*; D045868:Sorghum / Q000737:chemistry / Q000235:genetics*; D013213:Starch / Q000737:chemistry
chemical_list: D013213:Starch
keywords: Cereal crop; GWAS; Grain composition; Natural variation; Nutrition; QTL; Sorghum