GBS Analysis of Genetic Variation of Organic Acids in American Cranberry

This study focused on phenotypic variation of four organic acids found in cranberry fruit (Vaccinium macrocarpon Aiton); quinic acid (QA), benzoic acid (BA), citric acid (CA), and malic acid (MA). CA and MA are common in other fruit species and contribute to the tart taste of cranberries. QA and BA are quite unique to cranberry and have been associated with fruit rot resistance. Genetic variation for these acids is evident in our cranberry germplasm and breeding populations.  We evaluated variation in 99 progeny from a bi-parental cross between Budd’s Blues (high in BA and QA, and highly fruit rot resistant) and Crimson Queen (low in BA and QA). Fruit samples were collected at two points during the season, early in fruit development (Jul 30) and at fruit maturity (Oct 8), and concentrations of QA, BA, MA, and CA were determined using high performance liquid chromatography (HPLC). QA levels decreased from the first (immature) to second (mature) harvest date, BA and MA increased between the two dates, and CA remained fairly stable. Phenotypic variation in organic acid constituents in cranberry was evident at both stages of fruit development. For example on Oct 8, QA levels ranged from 10 to 20 mg/g among the 99 progeny; BA: 0.02-0.28 mg/g; CA: 5-13 mg/g; and MA: 3-9 mg/g. Genotyping by Sequencing (GBS) identified SNPs and a number of QTLs associated with levels of these organic acids.