Dissecting four correlated growth period traits using a genome-wide association study approach in soybean

Soybean [Glycine max (L.) Merr.] is a short-day, photoperiod-sensitive crop. The vegetative growth period (V), reproductive growth period (R), whole growth period (V + R) and the ratio of growth period structure (R/V) are photoperiod traits critical to adaptability and yield in soybean. To thoroughly dissect the genetic basis of these growth period traits and their correlations, a panel of 277 soybean accessions were genotyped with a single nucleotide polymorphisms (SNPs) panel and phenotyped at three field environments over three years. A genome-wide association study found 28 SNPs on fifteen chromosomes with 33 significant marker-trait associations, eleven, eight, four and ten for V, R, V + R and R/V, respectively. Two SNPs, Map-6077 and -6502, showed pleiotropy in three and two traits, respectively. Map-6077, associated with V, R, and V + R, was a synonymous SNP of the GmMFT, a member of PEBP family that has been reported to inhibit seed germination and regulate oil content. These results provide candidate SNP markers and genes for further functional experiments to advance molecular marker-assisted breeding.