2018 ASHS Annual Conference

Of all tomatoes consumed in New York State less than 10% are grown within state, creating a void in the availability of locally produced tomatoes. Greenhouse tomatoes are the largest greenhouse vegetable crop produced in the U.S. with over $400 million annual wholesale value. One of the challenges associated with growing tomatoes in upstate New York is the energy demands for heating and lighting. Use of supplemental CO₂ can reduce the need for supplemental lighting and increase crop yield in off-season. While CO₂ enrichment is known to increase crop yields, scientific literature is lacking on the interaction between CO₂ concentration and daily light integral (DLI) and subsequent photosynthetic and yield response of tomatoes.

The objective of this research is to study the interaction of supplemental CO₂ and lighting on tomatoes at different developmental stages. Phase 1 of this experiment uses climate controlled mini-chambers with 16 different treatment combinations conducted using four different CO2 concentrations (400, 600, 800, 1000 ppm) and light intensities (10, 15, 20, 25 mol•m^-2•day^-1 PAR) on juvenile ‘Merlice” tomato plants. After 10 days of exposure, plants are assessed for biomass, photosynthetic parameters, and morphological differences. An equation relating plant biomass and net photosynethic assimilation based on CO₂ and DLI is under development. In Phase 2, CO₂ and DLI will be controlled in a greenhouse to determine responses at the tomato fruiting stage.