Evaluation of Blackberry Cultivar Performance Under 30% Shade and Full Sun in Central Alabama

Abstract

Blackberry, the official state fruit of Alabama, has strong potential for expanded commercial production in the region. Yield, fruit quality, and environmental conditions of eighteen blackberry cultivars were evaluated over two harvest seasons (2024–2025) under full sun and 30% aluminet shade at the Chilton Research and Extension Center in central Alabama using a randomized complete block design (n = 8). Shade increased yield in 2024 but did not consistently improve yield in 2025, likely due to greater rainfall and soil moisture during the second year. Berry size was consistently greater under shade, and white drupelet disorder (WDD) incidence was reduced relative to full sun; however, shade also reduced soluble solids content and increased titratable acidity. Cultivar differences were observed for all measured variables. ‘Kiowa’, ‘Ponca’, and ‘Prime Ark® Horizon’ produced among the greatest cumulative yields across both years, whereas ‘Columbia Star’ and ‘Eclipse’ were among the lowest yielding and poorly adapted to central Alabama conditions. ‘Ponca’ and ‘Osage’ combined high yields with favorable fruit quality, low WDD incidence, and desirable flavor attributes. Although ‘Kiowa’ was consistently high yielding, it exhibited greater WDD incidence and lower soluble solids content than several other cultivars. Costly repairs to the shade structure were necessary during this study following storm damage, and caution should be exercised when determining whether to utilize a shade structure for blackberry production. Cultivar selection was observed to have a more consistent influence on yield, fruit quality, and WDD, and is likely a more economically impactful decision compared to utilizing shade structures in central Alabama.