Location: Application Technology Research Unit
Project Number: 3607-21000-015-33
Start Date: Aug 22, 2013
End Date: Jul 31, 2018
Specific projects that address resource use during the young plant and finished stages of greenhouse crop production that we will conducted at the University of Minnesota include: Young Plant Stage • Reducing energy inputs: o Evaluate LEDs for efficacy in flower induction of long-day plants and how that efficacy interacts with temperature and irradiance by using LEDs that vary in light quality and irradiance o There is a pervasive belief that carbon dioxide (CO2) is not limiting in greenhouses or that floriculture crops do not respond to supplemental CO2. Our earlier data clearly shows that many greenhouse crops benefit from adding CO2 to levels higher than 380 ppm (ambient). We will evaluate the impact of CO2 (200 – 1200 ppm) at the young plant stage (seedling/cutting stage) in growth chambers and track the impact of that work in the finishing greenhouse environment under ambient air conditions. Finished Plant Stage • Reducing chemical inputs: o Costs of applying growth retardants and pesticides have increased dramatically because of chemical and labor costs. We will identify innovative tank mixes and evaluate alternative application techniques (pH, rewetting, time of day, temperature/humidity, etc.) to maximize efficacy. We will also determine factors that affect plant absorption. We will also identify susceptible and resistant cultivars of at least 5 ornamental herbaceous crops to (bacteria, botrytis, powdery and/or downy mildew and whitefly, aphids, and/or mites; different species for different pests/diseases) and conduct studies to identify ways to increase resistance of susceptible plants. Some of that work will involve treatments to affect endogenous phytohormone levels including ethylene and jasmonate pathways. Efficacy will be evaluated using assessment of pest destruction and disease proliferation identified for each pest/disease and species. • Reducing energy inputs: o U.S. growers would benefit from crop-specific guidelines to help improve management of heating, cooling, shade and CO2 supplementation. We will develop lighting (50-800 umol m-2 s-1), temperature (10-35C) and CO2 standards (see above) that maximize growth and minimize energy inputs based on single leaf and/or whole plant photosynthetic response curves as plants develop and the leaf area indices change on at least 25 ornamental crops. Evaluated materials will include traditional woody/nursery plants materials that are propagated in greenhouses and/or forced in greenhouses.