Validating Markers Linked to Soluble Solids Content in Octoploid Strawberry

In Rosaceous crops including strawberry, the RosBREED project is focused on enabling marker-assisted breeding via identification as well as validation of markers that are associated with fruit quality traits. Around the world, strawberry is valued for its organoleptic characteristics and its nutritional content. Fruit quality traits have been prioritized in this crop. Flavor is the phenotypic result of a well synchronized combination of aroma compounds, sugars, acids and texture. The best strawberry flavor is obtained if high acids and sugars are in balance. Soluble solids content (SSC) includes mostly the concentration of sugars, followed by organic acids and soluble pectins and is positively correlated with sweetness perception and consumer likeness. The objectives of this study were: 1. to validate a previously identified QTL for SSC in 890 field-grown strawberry individuals for which SSC data were previously collected in 2011 and 2012, and 2. to identify genotypes with high SSC based on phenotypic and genotypic data. Fruit samples were collected and the resulting puree was used to measure the percent of soluble solids on a refractometer. Allele composition at the EMFv006 single sequence repeat (SSR) locus previously linked to high SSC content in the ‘Capitola’ × CF1116 strawberry population was determined after separation by capillary electrophoresis. Percent soluble solids content ranged from 3.1 to 18.7 in 2011 and between 3.7 and 16.6 in 2012 in the Oregon, and Michigan field-grown individuals evaluated.  Average SSC observed in MI and OR was 11% and 8.1%, respectively. The microsatellite allele dosage and configuration establishment (MADCE) method is being used to quantitatively establish the full allelic configuration at EMFv006. We will report association of the marker alleles and haplotypes with SSC content in strawberry.