Day-neutral Strawberries for High Tunnel Production in the Central United States

Abstract

Specialty crop production in high tunnel systems has greatly expanded in the central United States. Strawberry (Fragaria ×ananassa) may be a viable high-value crop for high tunnel growers, but fall-planted production systems have a high opportunity cost in regard to winter production space. This study investigates the feasibility of spring-planted day-neutral strawberry cultivars in a high tunnel production system in Kansas. Furthermore, the goals of this report are to identify day-neutral cultivars that are successful in this production system and investigate the utility of evaporative cooling (EC), as they relate to fruit yield and marketability as well as incidence of gray mold (caused by Botrytis cinerea). High tunnel trials were conducted at the Kansas State University Olathe Horticulture Research and Extension Center during 2014 and 2015. Six commercially available cultivars were evaluated: Albion, Evie 2, Monterey, Portola, San Andreas, and Seascape in both years. Mature fruit (90% to 100% red) were harvested twice weekly for total and marketable (fruit with no defects) fruit yield. The results indicate that ‘Portola’ had the highest total fruit weight in both years at 0.60 and 0.51 kg/plant, respectively, and was significantly higher than ‘Monterey’, ‘Albion’, and ‘San Andreas’ in both years (P < 0.05). In 2014, ‘Portola’, ‘San Andreas’, and ‘Albion’ produced the largest total fruit average weight (grams/fruit) and were significantly larger than ‘Seascape’ and ‘Evie 2’ (P < 0.05). In 2015, ‘Portola’ had significantly larger fruit than all the other cultivars except San Andreas (P < 0.05). Marketability percent by weight ranged from 76.5% to 88.6% across both years and the highest marketability was observed with ‘Albion’ (89% and 83%) and ‘Monterey’ (85% and 84%) in 2014 and 2015, respectively. An examination of fruit production during the early, mid-, and late seasons was used to determine seasonal dynamics of each cultivar and the high tunnel system. The overall trend was that total fruit weight was highest during the midseason and total average fruit weight was largest in the early season. However, ‘San Andreas’ and ‘Seascape’ had similar levels of production between the early and midseason and had the lowest level of production in the midseason, particularly in the 2015 trial. In our trials, the use of EC did not affect fruit weight or gray mold incidence on strawberry fruit. Based on the crop productivity observed in our study, this production system has the potential to extend the season for strawberry growers in the central United States or provide a high-value rotational crop for existing high tunnel growers that does not require winter production space.