J. Cody Rawls, Renee Threlfall,* Margaret Worthington, and Luke Howard
*University of Arkansas, 2650 N Young Ave, Fayetteville, AR 72704 (rthrelf@uark.edu)

Advances in muscadine grape (Vitis rotundifolia Michx.) breeding efforts have resulted in unique traits emerging with commercial, fresh-market potential. Harvest and post- harvest attributes of muscadine genotypes (cultivars and breeding selections) grown in Arkansas in 2020 were evaluated at the University of Arkansas System Division of Agriculture (UA System). Two cultivars (Summit and Supreme) and seven UA System selections were hand-harvested from the UA System Fruit Research Station, Clarksville. Approximately 1.8 kg of each genotype were harvested into clamshells and evaluated for physical attributes (berry weight, seed number, stem scar tear, and berry firmness) and composition (soluble solids, pH, titratable acidity, and soluble solids/titratable acidity ratio) at harvest and for postharvest attributes (weight loss and unmarketable berries) after 0, 14, or 28 days at 2°C. Genotype impacted all harvest attributes except seed number (3.11/berry). Berry weights at harvest ranged from 4.76 g (AM 77) to 12.50 g (AM 70), stem scar tear ranged from 0% (AM 26) to 30.61% (Supreme), and berry firmness ranged from 6.53 N (AM 135) to 10.75 N (Summit). For composition attributes at harvest, Supreme (17.43%) had the highest soluble solids, and AM 195 (3.80) had the highest pH. AM 77 had the highest titrat- able acidity (1.06%) and lowest soluble solids (11.37%), pH (2.81), and soluble solids/ titratable acidity ratio (10.75). AM 70 had the highest soluble solids/titratable acidity ratio (35.17) and lowest titratable acidity (0.43%). There was a significant genotype × storage interaction for both postharvest attributes. During storage, weight loss and unmarketable berries increased. AM 102 had the largest weight loss at 14 days (4.53%) and 28 days (7.83%). Supreme had the most unmarketable berries at 14 days (7.02%) and 28 days (24.56%). The ideal physical and composition attributes and high storage potential demonstrate potential for muscadines as a fresh-market crop.

Funding Support: none