Original Paper

Tree Genetics & Genomes

, Volume 7, Issue 2, pp 323-335

QTL analysis of fruit quality traits in two peach intraspecific populations and importance of maturity date pleiotropic effect

  • Iban EduardoAffiliated withParco Tecnologico PadanoIRTA. Centre de Recerca en Agrigenòmica CSIC-IRTA-UAB
  • , Igor PachecoAffiliated withDipartimento di Produzione Vegetale, Università degli Studi di Milano
  • , Giorgiana ChieteraAffiliated withDipartimento di Produzione Vegetale, Università degli Studi di Milano
  • , Daniele BassiAffiliated withDipartimento di Produzione Vegetale, Università degli Studi di Milano
  • , Carlo PozziAffiliated withParco Tecnologico Padano
  • , Alberto VecchiettiAffiliated withParco Tecnologico Padano
  • , Laura RossiniAffiliated withDipartimento di Produzione Vegetale, Università degli Studi di Milano Email author 

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Abstract

Two intraspecific peach breeding populations have been used to conduct a quantitative trait locus (QTL) analysis of fruit quality traits: an F1 from the cross Bolero (B) x OroA (O) and an F2 from the cross Contender (C) x Ambra (A). A total of 344 Prunus simple sequence repeats (SSRs) were analyzed in B, O, C, A parents and CxA F1 hybrid. Eight SSR were mapped for the first time in peach. A multiplex-ready polymerase chain reaction (PCR) protocol has allowed considerable time and cost saving during genotyping steps. Two maps (B map and O map) were produced for BxO population following the pseudo-test cross strategy and one for CxA. No marker could be mapped on G6 for the B map, on G4 and G8 for the O map and on G5 for the CxA map. Both populations were phenotyped over 2 years for maturity date (MD), fruit weight, external fruit skin overcolor, juice total soluble solids (SSC, Brix degree), juice titrable acidity and juice pH. Data for blooming time and flower type were scored only for BxO in 2007. All traits had a normal distribution, except for MD which was bimodal in BxO and trimodal in CxA, where it was scored as a co-dominant trait. Up to two QTLs per trait were detected in each population, and most of them were located in the same region forming clusters of QTLs, especially on G4. This is likely due to a major pleiotropic effect of MD masking the identification of other QTLs for different traits.

Keywords

Breeding Genomics Assisted selection Prunus persica (Batsch.) L. SSR Maturity date Peach Quality traits Molecular maps