Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/25/2005
Publication Date: N/A
Citation: Interpretive Summary: Tomato is one of the most commonly grown greenhouse crops in the United States. Various strategies for controlling environmental inputs, such as air temperature, have been used to obtain high fruit yields and predictable production schedules. More knowledge on tomato plant responses to the environmental conditions imposed during different stages of its life cycle can be used to improve these strategies. Experimental results showed that a two-week change in air temperature following the flowering of tomato plants could be used to control production scheduling and the quality of vine-ripened fruits. Warmer temperatures decreased the time to harvest and fruit size, and influenced nutritional and taste factors such as lycopene and fruit acidity. Cooler temperatures increased time to harvest and fruit size, and increased internal sugar content in the fruits. The work will be useful for scientists to understand how fruit quality, yield, and ripening time are influenced by environment in tomato. These data can be integrated with existing greenhouse management strategies to provide growers with an additional level of control over tomato production for meeting specific market demands.
Technical Abstract: Short-term changes in air temperature imposed after fruit-set may be suitable for controlling tomato production scheduling and improving quality of vine-ripened fruit. Three growth chamber experiments were conducted with hydoponically grown tomato (Lycopersicon esculentum Mill., cv. Laura) in which air temperature was altered from the control thermoperiod values of 23/18C for a two-week period starting at 10 days post fruit-set. Plants were returned to the control temperature value and fruits were harvested from the cluster at one of three ripening stages, breaker stage (taken as the point at which 25% of the fruit skin acquired a red tint), breaker stage plus three days, and breaker stage plus six days. A +/-5C (28/23C and 18/13C) temperature perturbation was used for two experiments and a +/-7C (30/25C and 15/11C) was used in a third experiment for the two-week period. A similar increase in harvest window, reduced time to harvest (between 5.5 and 7.4 days) and reduced fruit mass (by an average 35.0 grams per fruit) was observed for both high temperature treatments compared with the control group. Low temperature treatments increased fruit mass as compared to the control group (by an average of 14.5 grams per fruit) while only the 15/11°C delayed time to harvest by 2.6 days. Quality parameters were significantly different between temperature treatments for color indices, soluble solids, acidity, viscosity, and lycopene content at each vine-ripened stage. The results demonstrate that the temperature treatments altered the rate at which changes occurred in the external appearance of the fruit (color) and the internal characteristics (such as soluble solids, acidity, consistency, etc.) as compared to the control group. The results will be suitable for developing more effective environmental control strategies for tomato growers.