2018 ASHS Annual Conference

Fruit quality traits have significant effect on consumer acceptance and subsequently on the consumption of peach (Prunus persica L. Batsch). The improvement of quality traits such as sweetness, flavor, and texture can be enhanced throughout QTL discovery and validation to enable the use of marker assisted breeding (MAB). A Bayesian QTL mapping approach implemented in FlexQTL^TM software has been conducted on seven F₁ low to medium chill families along with the founders and parents. Phenotypic data were collected for two years at a high chill (Clovis, CA) and a medium chill (College Station, TX) location (Clovis) and genotyped using the 9K SNP Illumina array. The objective of this study was to discover and/or validate the number and positions of quantitative trait loci (QTL) for three quality traits: titratable acidity (TA), soluble solid content (SSC), and fruit skin blush (Blsh). Fourteen QTLs were identified for the three traits across the environments: eight QTLs with strong and decisive evidence and the other six QTLs with positive evidence. Several QTLs were reported in previous studies and a few were novel QTLs. QTLs for SSC in TX 2012 and TA in TX 2013 were not mapped because of lack of phenotypic data. The proportion of phenotypic variance explained (PVE) by a QTL for the three traits ranged from 18.9 to 94.8%. This approach would help to develop DNA marker test and subsequent marker-assisted breeding for developing new peach cultivars of superior quality traits.