Artículo de publicación ISIPeach and nectarine quality traits such as flavor, texture, and juiciness are important for consumer acceptance. Maturity date (MD) also plays a role in the fruit-ripening process and is an important factor for marketing fresh fruit. On the other hand, cold storage produces a physiological disorder known as chilling injury where the most important symptom is a lack of juice in the flesh or mealiness (M). In this study, we analyzed an F2 population obtained from a self-pollination of "Venus" nectarine that segregates for MD and M. We built a linkage map with 1,830 SNPs, 7 SSRs and two slow-ripening (SR) morphological markers, spanning 389.2 cM distributed over eight linkage groups (LGs). The SR trait was mapped to LG4 and we compared the whole genome sequences of a SR individual and "Venus" and identified a deletion of 26.6 kb containing ppa008301m (ANAC072) co-localized with the SR trait. Three Quantitative Trait Loci (QTL) for MD were detected; they all co-localize on LG4 between 31.0 and 42.0 cM. Four co-localizing QTLs on LG4 between 33.3 and 40.3 cM were detected for M, explaining 34 % of the phenotypic variation. We identified five and nine candidate genes (CGs) for MD and M from the QTL regions, respectively. Our results suggest that the transcription factors (TFs) ANAC072 and ppa010982m (ERF4) are CGs for both traits. LG4 contains a cluster for genetic factors that possibly regulate MandMD, but functional validation is necessary to unravel the complexity of genetic control responsible for fruit traits.Conicyt-Fondecyt 11121396 Conicyt-FONDEF G13i10005 Corfo-Innova 09PMG-7240 Fondo de Areas Prioritarias Centro de Regulacion del Genoma 15090007 UNAB DI-489-14R CONICYT D-21090737 PFB-1

The peach [Prunus persica L. (Batsch)] slow ripening (SR) trait is a mutation preventing the normal ripening process. Individuals with this phenotype are discarded in peach breeding programs. This trait is determined by a single gene (Sr/sr), where the recessive homozygote (sr/sr) confers the SR phenotype, and has been mapped to linkage group 4 of the peach genome. A large deletion of 26.6 kb containing the sequence of a NAC transcription factor has been proposed as the causal mutation. Two dominant markers based on the sequence of this region have been assayed previously and found to be diagnostic (genotypes always predicted the phenotypes). However, their dominant nature-a null allele for the marker was associated with the sr allele-made it impossible to predict the individuals that carried the SR trait. Here we used resequencing information to develop a codominant molecular marker for the SR trait in peach. The marker was validated in the 'Belbinette' 9 'Nectalady' F1 and the 'Venus' F2 populations, and in 27 lines, 18 of which are known to carry the sr allele. The marker cosegregated with the SR phenotype in all cases, allowing the discrimination of two DNA fragments of different size associated with normal-ripening alleles, in addition to a third fragment associated with the sr allele. The utility of this marker in peach breeding programs is discussed.Spanish Ministry of Economy and Knowledge AGL2012-40228-C02-01 Fondo de Areas Prioritarias Centro de Regulacion del Genoma 15090007 CORFO Consorcio Biofrutales 13 CTI-21520-SP03 13 CTI-21520-SP04 FONDECYT 1160584 FONDEF Genoma G13i10005 CORFO-Innova 09PMG724