QTL Analysis for Fruit Quality Traits in Peach [Prunus persica (L.) Batsch]

Chile is the first peach exporter in the South Hemisphere and the fifth producer in the world. Chilean initiatives of peach breeding have been carried out, where the fruit quality and postharvest performance are the main goals for the new peach varieties. Breeding is a time consuming and costly process. For this reason, the development of genomic tools to support the early selection of genotypes is quite relevant to improve the efficiency of breeding programs. Thus, the aim of this work was to identify genome regions associated to fruit quality traits in peach using a QTL analysis. The segregating population of 151 individuals obtained from Venus x Venus was evaluated in four periods: Harvest, harvest + shelf life, 21 days at 0 °C and 21 days at 0 °C + shelf life. Firmness, weight, color, soluble solids content, titratable acidity, ripening time, browning and mealiness were evaluated. The segregating population was genotyped with microsatellite markers (SSRs) and SNPs using 9K SNP array for peach. A linkage map was built with 1,820 markers, which were mapped in 8 linkage groups. The resulting map spanned a total distance of 382.9 cM with an average of 0.21 cM between adjacent markers. A QTL for titratable acidity was associated to chromosome 1 (5.2 Mbp with 42% variance explained) and in chromosome 4, QTLs for weight (2 Mbp with 15% variance explained), soluble solids content (1.9 Mbp with 32% variance explained) and two for mealiness (6.53 Mbp and 0.5 Mbp with 35% and 41% variance explained respectively) were detected. Currently, additional work has being done in order to get new molecular markers related to fruit quality traits. (This work was supported by Fondecyt 11121396, FONDAP CRG 15070009, Núcleo Milenio P10-062-F and Basal PFB-16).