Identification of Quantitative Trait Loci (QTLs) for Fruit Quality Traits in Apple

A segregating mapping population of Co-op 17 x Co-op 16 was used to identify quantitative trait loci (QTLs) associated with various fruit quality traits in apple. Phenotypic data were collected over 2 years for fruit circumference (in centimeter), diameter at midpoint (in centimeter), length (in centimeter), weight (in gram), total soluble solids (in degree Brix), and total titratable acids (in percent) for the segregating population. The phenotypic data along with a previously constructed genetic map, based on simple sequence repeat markers derived from expressed sequence tag and bacterial artificial chromosome end sequence databases, were used in marker-trait association analysis. Interval mapping identified two QTLs linked to fruit size components on linkage groups 03 and 05 with limit of detection scores of 3.27-4.06 and 3.29-4.02 along with phenotypic variation accounting for 15.4-46.4 and 18.3-21.9 %, respectively.