2017 ASHS Annual Conference

Strawberry (Fragaria ×ananassa) is consumed for its flavor and health benefits. Over the last two decades, several quantitative trait loci (QTL) analysis studies for consumer traits were conducted using low-density genetic maps. The previous studies utilized low-throughput genotyping methodologies. The IStraw90^® single nucleotide polymorphism (SNP) array enabled QTL studies using high-density SNP genetic maps, which can be linked to physical genome positions. In this study, breeder-relevant traits, evaluated in Michigan (MI) and Oregon (OR) from the ‘RosBREED: Enabling Marker-Assisted Breeding in Rosaceae’ project, were analyzed using a pedigree-based QTL analysis approach. During the two years of evaluation in OR and MI, QTLs were validated for soluble solid content (SSC), fruit weight (FWT), pH, and flowering habit and unique QTLs were detected for FWT and titratable acidity (TA). For fruit quality, a QTL for SSC on linkage group (LG) 6A, four QTLs for FWT (LGs 1B, 2BII, 3C, and 4A), two QTLs for pH (LGs 4D and 4CII), and two QTLs for TA (LGs 2A and 7A) were detected. In addition, a large-effect QTL for flowering habit was detected at the distal end of LG 4A coinciding with the FaPFRU locus in F. ×ananassa. Haplotyping of FaPFRU indicated that the homozygous recessive genotype was highly predictive of seasonal flowering (SF). SNP probes identified in the FaPFRU region may be helpful for the development of DNA-based markers for selecting flowering habit.