Quantifying Temperature Effects on Development Rate and Plant Quality of Compact Container-grown Tomato

Abstract

Mean daily temperature effects on plant development rates and quality were evaluated for compact container-grown tomato (Solanum lycopersicum). Compact tomato varieties ‘Siam’ and ‘Red Velvet’ were grown in greenhouses at 18 to 26 °C (Expt. 1) and 20 to 30 °C (Expt. 2) under supplemental high-pressure sodium lighting and 16-h photoperiod. The number of days to first open flower, first ripe fruit and from flower to ripe fruit were measured and development rates calculated by taking the reciprocal (e.g., 1/d). Temperature effects were predicted by fitting a linear (for first open flower) and a nonlinear exponential function (for first ripe fruit and between first open flower and ripe fruit), which included base temperature (Tmin) and maximum developmental rate (Rmax, 1/d) parameters. Plant quality attributes were measured in Expt. 2. As temperature increased, the time to flower and fruit decreased (i.e., developmental rates increased) for both varieties. Estimated Tmin was 8.7 °C for ‘Siam’ and 11.4 °C for ‘Red Velvet’, whereas Rmax was similar between cultivars (0.030 at fruit and 0.037 from flower to fruit). ‘Siam’ and ‘Red Velvet’ grown at ≈25 °C had a relatively short crop time, compact canopy, adequate fruit size, and a high number of fruits per plant at finish. Compact tomatoes are new crops being grown by greenhouse floriculture operations for ornamental and edible value, and the information from this study can help growers schedule these crops to meet critical market windows and determine the impacts of changing growing temperature on crop timing and quality.

Keywords

• edibles
• floriculture
• flowering
• fruiting
• lycospersicum
• scheduling