Exploring and exploiting phenotypic and genetic diversity in peach : identification of major genes and QTLs by GWAS

Genetic variability is a key requirement for breeding. Although new peach cultivars are released yearly to the market, the genetic pool of cultivated peaches is very limited. To evaluate the variability available in commercial but also in old local peach accessions we selected a panel of 1,580 accessions maintained and evaluated in four European and one Chinese germplasm collections. Phenotypic data collected over years following common protocols have been integrated in a database, generating a useful tool for breeders and researchers. These accessions were genotyped with the peach 9K SNP array v1. T. Genotypic data distributed the accessions in three main subpopulations (Occidental obtained in breeding programs, Occidental old local varieties and Chinese cultivars). Linkage disequilibrium (LD) was in agreement with previous studies reporting long extension. Phenotypic and genotypic data have been combined in a GWAS study allowing the design of markers for marker assisted selection (MAS). Preliminary analyses on quantitative traits are promising, while further analysis will be required to integrate all data in a single genome-wide association analysis.