Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 18, 2008
Publication Date: November 21, 2008
Citation: Takeda, F., Glenn, D.M., Stutte, G. 2008. Red light affects flowering under long days in a short-day strawberry cultivar. HortScience. 43(7):2245-2247. Interpretive Summary: In the mid-Atlantic coast region, the main strawberry harvest season is from early May to late June. Out-of-season fruit production in the region is low. We developed a simple propagation scheme for short-day type strawberry cultivars to produce fruit in fall and spring in high tunnels without using standard conditioning treatments such as chilling or artificial short-day photoperiod, during the nursery phase. When runner tips of a short-day type cultivar were started as plug plants in early July and field planted around 1 September more than 86% flowered by mid October and produced 3/4 pound of fruit by late December. The results of this study suggest that transplants of short-day type strawberries that will flower in fall can be produced by developing a plant canopy that alters the quality of light illuminating the crown. This technique can be used to increase high quality out-of-season strawberry production when returns will be high.
Technical Abstract: The effect on flower bud induction of red light (600-700 nm) directed at the crowns of short-day 'Strawberry Festival' strawberry transplants was investigated. July-plugged transplants were maintained under a long-day photoperiod in August. Illuminating the crown for 16 h-day-1 with small red light emitting diode (LED) lamps for approximately 4 weeks in August decreased the number of transplants that flowered by mid October. Due to high plant density, the plants developed a high leaf area index (LAI) above the crowns and the crown near the base of leaf petioles was completely shaded. Light reaching the crowns was depleted in wavelengths less than 700 nm because of absorption by the canopy. The results suggest that the absence of red light on the crown has a quantitative effect on flower bud induction in 'Strawberry Festival' transplants under non-photo inductive conditions.