Total and marketable yield, fruit size and fruit rot were evaluated for `Camarosa' and `Ventana' strawberries grown with or without protected culture in southern California in 2003 and 2004. In both years, bareroot transplants were established on 5 Oct. using standard “open field” production methods. Fifty-five days after transplanting, metal posts and arcs were positioned over portions of the field and covered with 0.0324-mm-thick clear polyethylene (Tufflite Thermal, Tyco Plastics, Inc., Minneapolis, Minn.) to create “tunnel” structures 5 m wide, 25 m long, and 2.5 m high. Each tunnel covered three contiguous strawberry beds, and experiment design was a randomized complete block with four replications, with individual plots consisting of 20 plants. In 2003, early season (Jan.–1 Apr.) marketable yields in tunnels were 90% and 84% greater than outdoor culture for `Ventana' and `Camarosa', respectively. In 2004, use of tunnels resulted in a 140% marketable yield increase for `Ventana' and 62% for `Camarosa' (Jan.–31 Mar.); however, unusually high temperatures (38 °C) in April resulted in reduced yields in tunnels thereafter. In both years, increased early production coincided with highest fresh market fruit prices, resulting in $5700–7700 greater returns per-acre compared to open field production. For both cultivars, tunnel production resulted in 37% to 63% fewer non-marketable fruit due to less rain damage, better fruit shape, and decreased incidence of gray mold. For all treatments, fruit size decreased as the season progressed and was more pronounced in tunnels after April. Overall, these studies indicate that tunnels have potential for enhancing early-season production and profitability of strawberries in southern California.
Biostimulants affect quality and yield of tomato fruits from open-field production
