title: QTL analysis of soft scald in two apple populations.
abstract: The apple (Malus×domestica Borkh.) is one of the world's most widely grown and valuable fruit crops. With demand for apples year round, storability has emerged as an important consideration for apple breeding programs. Soft scald is a cold storage-related disorder that results in sunken, darkened tissue on the fruit surface. Apple breeders are keen to generate new cultivars that do not suffer from soft scald and can thus be marketed year round. Traditional breeding approaches are protracted and labor intensive, and therefore marker-assisted selection (MAS) is a valuable tool for breeders. To advance MAS for storage disorders in apple, we used genotyping-by-sequencing (GBS) to generate high-density genetic maps in two F1 apple populations, which were then used for quantitative trait locus (QTL) mapping of soft scald. In total, 900 million DNA sequence reads were generated, but after several data filtering steps, only 2% of reads were ultimately used to create two genetic maps that included 1918 and 2818 single-nucleotide polymorphisms. Two QTL associated with soft scald were identified in one of the bi-parental populations originating from parent 11W-12-11, an advanced breeding line. This study demonstrates the utility of next-generation DNA sequencing technologies for QTL mapping in F1 populations, and provides a basis for the advancement of MAS to improve storability of apples.
authors.affiliation: Department of Plant and Animal Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia B2N 5E3, Canada; Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Kendra A
authors.initials: KA
authors.lastname: McClure
authors.affiliation: Agriculture and Agri-Food Canada, Fredericton Research and Development Centre , Fredericton, New Brunswick E3B 4Z7, Canada.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Gardner
authors.affiliation: Agriculture and Agri-Food Canada, Summerland Research and Development Centre , Summerland, British Columbia V0H 1Z0, Canada.
authors.forename: Peter Ma
authors.initials: PM
authors.lastname: Toivonen
authors.affiliation: Agriculture and Agri-Food Canada, Summerland Research and Development Centre , Summerland, British Columbia V0H 1Z0, Canada.
authors.forename: Cheryl R
authors.initials: CR
authors.lastname: Hampson
authors.affiliation: Agriculture and Agri-Food Canada, Kentville Research and Development Centre , Kentville, Nova Scotia, Canada B4N 1J5.
authors.forename: Jun
authors.initials: J
authors.lastname: Song
authors.affiliation: Agriculture and Agri-Food Canada, Kentville Research and Development Centre , Kentville, Nova Scotia, Canada B4N 1J5.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Forney
authors.affiliation: Agriculture and Agri-Food Canada, Kentville Research and Development Centre , Kentville, Nova Scotia, Canada B4N 1J5.
authors.forename: John
authors.initials: J
authors.lastname: DeLong
authors.affiliation: Department of Plant Agriculture, Crop Science Building, University of Guelph , Guelph, Ontario N1G 2W1, Canada.
authors.forename: Istvan
authors.initials: I
authors.lastname: Rajcan
authors.affiliation: Department of Plant and Animal Sciences, Faculty of Agriculture, Dalhousie University , Truro, Nova Scotia B2N 5E3, Canada.
authors.forename: Sean
authors.initials: S
authors.lastname: Myles