The Genetic Architecture of Strawberry Yield and Fruit Quality Traits

Abstract

Over the last two centuries breeders have drastically modified the fruit quality of strawberries through artificial selection. However, there remains significant variation in quality across germplasm with scope for further improvements to be made. We report extensive phenotyping of fruit quality and yield traits in a multi-parental strawberry population to allow genomic prediction and QTL identification, thereby enabling the description of genetic architecture to inform the efficacy of implementing advanced breeding strategies. A trade-off was observed between two essential traits: sugar content and class one yield. This result highlights an established dilemma for strawberry breeders and a need to uncouple the relationship, particularly under June-bearing, protected production systems comparable to this study. A large effect QTL was associated with perceived acidity and pH whereas multiple loci were associated with firmness, we therefore recommend the implementation of both MAS and genomic prediction to capture the observed variation respectively. Ultimately, our results suggest that the best method to improve strawberry yield is through selecting parental lines based upon the number of marketable fruit produced per plant. Strawberry number metrics were less influenced by environmental fluctuations and had a larger additive genetic component when compared to mass traits. As such, selecting using "number" traits should lead to faster genetic gain. Finally, we identify a large effect locus associated with an increase in class one fruit.