Refining the Genomic Region Containing a Major Locus Controlling Fruit Maturity in Peach

Date to fruit maturity (DTFM), defined as the duration between full bloom and maturity, is highly variable in peach [Prunus persica (L.) Batsch].  Identifying molecular markers associated with DTFM will greatly aid peach breeders in marker assisted selection (MAS) targeted towards producing peach cultivars that mature during different maturity windows during the season.  A population consisting of 133 diverse peach accessions was used to conduct a genome wide association study (GWAS).  Each accession was phenotypically evaluated for (i) flowering date (FD) (Julian day when ~ 50% of the flowers on the tree had reached full bloom) and (ii) Maturity date (MD) (Julian day when ~ 50% of the fruit on the tree reached market maturity). DTFM was calculated by subtracting FD from MD; each accession was genotyped using genotyping-by-sequencing (GBS).   The GWAS results revealed a 46.3 kbp locus on chromosome 4 that was highly associated with DTFM.  The position of the locus identified in this study differed from the position of a previously reported locus associated with DTFM. The genomic region identified in this study plays a major role in regulating the length of time to complete fruit maturity and ripening in peach. The data reported here will aid peach and other Prunus spp. breeders in MAS targeted towards widening peach germplasm for maturity, particularly early maturity.