Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2003
Publication Date: N/A
Two growth chamber experiments were conducted with tomato (Lycopersicon esculentum Mill., cultivar Laura) to investigate the effects of 14 day air temperature perturbations on production and scheduling of vine-ripened tomato fruit. Plants were grown in 6" pots filled with perlite, pruned to a single truss, and irrigated using drip-irrigation. Plants were subjected to either a high (28°C/23°C), control (23°C/18°C), or low (18°C/13°C) day/night temperature for a 14-day period beginning ten days after fruit set. Before and after those fourteen days a 23°/18°C day/night temperature was utilized. All other environmental conditions were equal between treatments, including set-points of 400 µmol m-2 s-1 PPF (photosynthetic photon flux), 75% relative humidity, 1000 µmol mol-1 atmospheric carbon dioxide concentration, and 16 hour photoperiod. Results for the two experiments show a significant reduction (4.5 days) in the time to harvest due to the high temperature treatment. A production scheduling model that predicts flowering and harvest dates based on the amount of PAR (photosynthetically active radiation) received by the plant between seedling emergence and flowering dates was modified to incorporate temperature effects based on these results. A thermal time approach was used to calculate a requirement for plants to accumulate 739°C-days (with a base temperature of 4.75°C) during the period between flowering and breaker stage. When coupled with the original model, this requirement addresses the influence of temperature perturbations in predictions of harvest date for single truss tomato production. With further refinement and validation, the model can be beneficial for greenhouse growers to appropriately manage and utilize resources in consideration of market demand.