Genome-wide Association Studies of Agronomic Traits Consisting of Field- and Molecular-based Phenotypes

Genome-wide association study (GWAS) is a powerful approach to identify the genetic factors underlying the intraspecific phenotypic variations. Recent advances in DNA sequencing technology, including next generation sequencing has enabled us to easily genotype high density genome-wide SNPs. In addition, many accessions of various plant species have been widely collected in recent years. These genetic resources have made GWAS a markedly more popular approach for investigation of natural variations occurring in various traits using large populations. In addition to genotyping technology, advances in high-throughput phenotyping technologies have enabled us to acquire variation data on a large number of accessions characterized for various traits, including not only the field traits (e.g., yield and disease resistance) but also molecular traits (e.g., gene expression level and metabolite content). Thus, it is possible to expand the range of application of GWAS and enhance the detection power of genomic association. In this review, we summarize recent GWAS of various agronomic traits at field and molecular scale, following which we highlight the integration approach involving GWAS and high-throughput phenotyping technologies including transcriptome, ionome and metabolome.