Quality of day-neutral strawberries grown in a high tunnel system

Abstract

Spring-planted, day-neutral strawberry (Fragaria x ananassa) production within a high tunnel system could provide growers with season extension and enhanced postharvest quality. This study identified which spring-planted, day-neutral strawberry cultivars are successful in a plasticulture, high tunnel system, while investigating the utility of an evaporative cooling system (EC), with regard to quality at harvest and throughout storage. The trial was conducted at Kansas State University Olathe Horticulture Research and Extension Center (OHREC) during the 2014 and 2015 growing seasons. Six commercially-available cultivars were evaluated, ‘Albion’, ‘Evie 2’, ‘Monterey’, ‘Portola’, ‘San Andreas’, and ‘Seascape’. Mature fruit (90–100 % red) were harvested twice weekly and three harvests were evaluated for the quality. Respiration rate, moisture content, and overall visual quality, using a scale from 5 (excellent) to 1 (poor), were monitored every 24 h. Flesh firmness, color, soluble solids content (SSC), and titratable acidity (TA) were evaluated at harvest and every other day throughout storage. Nutritional quality (total phenolic and antioxidant capacity) was evaluated at harvest. ‘Monterey’, ‘Seascape’, and ‘Albion’ had the highest SSC (P < 0.001) at 8.22, 7.82, and 7.81 %, respectively. While ‘Monterey’ and ‘Albion’ also produced the darkest fruit (L*). Nutritional quality (as determined by ORAC and total phenolic content) was statistically similar for ‘Albion’, ‘Evie 2’, ‘Monterey’, ‘San Andreas’, and ‘Seascape’, which were higher than ‘Portola’ (P < 0.05). Results show ‘Albion’, ‘Monterey’, ‘San Andreas’, and ‘Portola’ maintained flesh firmness (P < 0.001), and maintained their overall visual quality (P < 0.001) past day 6, compared to ‘Evie 2’ and ‘Seascape’. The strawberries grown with EC system were lighter (P < 0.01), and had a lower total phenolic content (P < 0.01) than the fruit grown without EC. However, minimal postharvest effects due to the use of EC were observed. This research identified cultivars that perform optimally concerning quality at harvest and throughout storage while investigating the utility of EC.