title: Grain protein content variation and its association analysis in barley.
abstract: BACKGROUND
  Grain protein content (GPC) is an important quality determinant for barley used as malt, feed as well as food. It is controlled by a complex genetic system. GPC differs greatly among barley genotypes and is also variable across different environments. It is imperative to understand the genetic control of barley GPC and identify the genotypes with less variation under the different environments.
  
  
  RESULTS
  In this study, 59 cultivated and 99 Tibetan wild barley genotypes were used for a genome-wide association study (GWAS) and a multi-platform candidate gene-based association analysis, in order to identify the molecular markers associated with GPC. Tibetan wild barley had higher GPC than cultivated barley. The significant correlation between GPC and diastatic power (DP), and malt extract confirmed the importance of GPC in determining malt quality. Diversity arrays technology (DArT) markers associated with barley GPC were detected by GWAS. In addition, GWAS revealed two HvNAM genes as the candidate genes controlling GPC. No association was detected between HvNAM1 polymorphism and GPC, while a single nucleotide polymorphism (SNP) (798, P < 0.01), located within the second intron of HvNAM2, was associated with GPC. There was a significant correlation between haplotypes of HvNAM1, HvNAM2 and GPC in barley.
  
  
  CONCLUSIONS
  The GWAS and candidate gene based-association study may be effectively used to determine the genetic variation of GPC in barley. The DArT markers and the polymorphism of HvNAM genes identified in this study are useful in developing high quality barley cultivars in the future. HvNAM genes could play a role in controlling barley GPC.
authors: Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou 310058, China.
authors: Shengguan
authors: S
authors: Cai
authors: Gang
authors: G
authors: Yu
authors: Xianhong
authors: X
authors: Chen
authors: Yechang
authors: Y
authors: Huang
authors: Xiaogang
authors: X
authors: Jiang
authors: Guoping
authors: G
authors: Zhang
authors: Xiaoli
authors: X
authors: Jin
mesh_terms: D002523:Edible Grain / Q000235:genetics / Q000378:metabolism*; D055106:Genome-Wide Association Study / Q000379:methods*; D006239:Haplotypes / Q000235:genetics; D001467:Hordeum / Q000235:genetics*; D015810:Linkage Disequilibrium / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics
chemical_list: D010940:Plant Proteins