Evaluation of blackberry cultivars and breeding selections for fruit quality traits and flowering and fruiting dates

Authors: Lewers, Kimberly; Wang, Shiow; Vinyard, Bryan

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2010
Publication Date: 11/1/2010
Citation: Lewers, K.S., Wang, S.Y., Vinyard, B.T. 2010. Evaluation of blackberry cultivars and breeding selections for fruit quality traits and flowering and fruiting dates. Crop Science. 50(6):2475-2491.

Interpretive Summary: We compared 122 blackberry cultivars and breeding selections for antioxidant levels, flavor, and flowering and fruiting seasons in order to help farmers and blackberry breeders better select blackberry varieties. In addition to finding a tremendous range for all traits observed, we found that late-flowering blackberries tend to be sweeter and higher in anti-oxidants. Blackberry breeders and farmers will be interested in using these findings to provide delicious blackberry fruit high in antioxidants to consumers.

Technical Abstract: A collection of 122 Rubus (L.) cultivars and breeding selections, primarily semi-erect Eastern blackberry, were evaluated for fruit antioxidant capacity (ORAC), total phenolics, total anthocyanins, percentage soluble solids, titratable acids, flowering dates and fruiting dates. The highly correlated traits of antioxidant capacity, total phenolics and total anthocyanins varied by over three-fold, and the high consistent correlation, within and across years, suggests indirect selection for genotypes with high antioxidant capacity may be more time- and cost-efficient than direct selection. Some genotypes were more than twice as sweet or twice as tart as others, and the ratio of percentage soluble solids to titratable acids varied by more than three-fold. There were no significant genotype-by-year interactions for percentage soluble solids, or the ratio of soluble solids and titratable acids (SSC/TA), so selection for these important flavor components could be made in a single year of replicated testing. The date of first open flower ranged from the third week of April through mid-June, a 54-day range in dates. The date of first ripe fruit ranged from early June to the third week in July, a 51-day range. The dates of first open flower and first ripe fruit were well correlated, even thought the difference between the two, the fruit development period, varied from around one to two months. Interestingly, the date of first open flower was significantly correlated with most of the other traits. Late-flowering genotypes tended to have shorter fruit development periods and fruit that was both sweeter and higher in antioxidant capacity, yet the fruiting season duration tended to be shorter.