Bacterial spot resistance in peach: functional allele distribution in breeding germplasm

• Published in: Acta horticulturae no. 1084; pp. 69 - 74
• Main Authors: Gasic, K, Reighard, G, Okie, W, Clark, J, Gradziel, T, Byrne, D, Peace, C, Stegmeir, T, Rosyara, U, Iezzoni, A
• Format: Journal Article
• Language: English
• Published: International Society for Horticultural Science 01-01-2015
• Subjects: alleles; breeding; consumer demand; cracking; cultivars; defoliation; DNA; fruit growing; germplasm; loci; peaches; Prunus persica; quantitative trait loci; Xanthomonas arboricola pv. pruni; United States
• ISSN: 0567-7572; 2406-6168
• DOI: 10.17660/ActaHortic.2015.1084.7

Bacterial spot, caused by Xanthomonas arboricola pv. pruni, is a serious economic disease causing severe defoliation and black surface pitting, cracking or blemishes on peach fruit worldwide. A management option for control and meeting consumer demand for chemical-free, environmentally friendly fruit production is the development of resistant or tolerant cultivars. Resistance to bacterial spot in peach cultivars is apparently under polygenic control. Several controlling loci in the peach genome conferring quantitative resistance were recently discovered in an F2 population. The two quantitative trait loci (QTLs) with the largest effects on bacterial spot resistance in peach fruit, Xap.Pp.OC-1.2 and Xap.Pp.OC-6.1, were validated here in a large collection of U.S. peach breeding germplasm (Prunus persica and some closely related species). High-resolution genome scans of this germplasm conducted within the RosBREED project were associated with phenotypic data on fruit bacterial spot resistance to determine effects and distributions of functional alleles. This resulting predictive DNA information has immediate application in U.S. peach breeding.