Mapping QTL underlying fruit quality traits in an F1 strawberry population

Understanding how strawberry nutritional and quality traits are genetically regulated and correlated is an essential step towards improving marker-assisted breeding programmes in this crop. A first step to achieve this goal was to construct a Single Nucleotide Polymorphism (SNP)- based genetic map of 140 F1 individuals of a cross between the two octoploid parents ‘Redgauntlet’ and ‘Hapil’. The map consisted of 3933 SNPs distributed over 28 linkage groups, representing the seven homoeologous groups expected in Fragaria (2n = 8x = 56), and covered a total length of 2624.7 cM with an average resolution of 0.7 cM/SNP. Two overlapping subsets of F1 individuals were evaluated in the field and glasshouse at East Malling Research and the University of Reading, respectively. Negative correlation was observed between Pelargonidin and the three traits L*, a* and b*, whereas positive correlations were observed within L*, a* and b*, and between Ellagic acid, Pelargonidin, and Cyanidin at both trial locations. QTL mapping revealed 29 significant QTL associated with the measured traits and mapped over 16 linkage groups. Two QTL for fruit Fresh Weight (FW) were co-located between day 1 and day 4 of shelf life, accounting for over 62 % of the variation. These data will enhance our understanding of the genetic basis and correlation of strawberry quality traits and provide the basis for refining QTL that underpin the genetic regulation of these quality traits.