Genome-wide association study of the husk number and weight in maize (Zea mays L.)

Abstract

Maize husk number and weight are two vital traits, influencing the grain drying rate after physiological maturity, shattering and breakage rate in the progress of combine harvesting, in breeding varieties suitable for mechanized harvest. Unveiling the genetic basis of the husk number and weight would be useful for guiding maize genetic improvement of mechanical harvesting. The present study is the first to conduct a genome-wide association study of the husk number and weight. In this study, 253 maize inbred lines were evaluated in three environments to detect single nucleotide polymorphisms (SNPs) for the husk number and weight using the Maize SNP3 K Beadchip. Based on the mixed linear model, 24 associated SNPs for husk number and 29 associated SNPs for husk weight were detected with P < 0.001 in different environments as well as the best linear unbiased predictions over all environments. Eight and nine stable SNPs for husk number and weight were detected in all environments, respectively. Based on the phenotypic effects of the alleles of these stable SNPs, the favorable alleles were mined. Several typical accessions harboring favorable alleles with elite phenotypic performance of husk number and weight were identified, such as T53, BJT4, Zong3, A489, and BJT6. Five elite parental combinations were predicted for reducing maize husk number and weight. These results might serve as a basis for quantitative trait loci fine mapping and the genetic improvement of maize husk number and weight through molecular marker-assisted approach.