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United States Department of Agriculture

Agricultural Research Service

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Research Project: Improved Production Methods: North South Initiative (University of Minnesota)

Location: Application Technology Research

2010 Annual Report

1a. Objectives (from AD-416)
The objective of this unified research effort is to improve the efficiency of plant production through a multi-disciplinary team approach that focuses on scheduling, the environment, energy, nutrient, water, and chemical growth regulator resources.

1b. Approach (from AD-416)
Develop protocols to flower plants at a specified plant size for the retail environment, and extending the marketing season by producing early- or late-flowering plants for different locations in the U.S. A single product or tank mix growth retardant applications for new crops that reduce elongation most without delaying flowering and whether innovative practices such as rewetting of foliage increases efficiency of growth regulators. Identify the crops and stages of development in which lighting is most effective. In addition, photoperiodic lighting is increasingly being used to induce earlier flowering during the winter and spring. Determine how photoperiodic lighting can be maximized by investigating how light quantity, quality, and duration (including cyclic lighting) impact flowering of a range of popular garden plants. Potential energy savings will be quantified by optimizing light and temperature to produce crops in the most efficient and cost-effective manner for different locations in the U.S. Develop tools and techniques that allow growers to more precisely control and manipulate flowering of greenhouse crops. Techniques will be developed for producing 'programmed' liners that have the branching, height potential, and flower bud development necessary so that the liner can be simply transplanted and quickly finished. "Bud meters" will be developed for important floriculture crops so that growers can manage greenhouse environments in order to properly time flowering on finished crops or to possibly reduce greenhouse temperatures to save fuel costs while still hitting the targeted market dates. Determine optimal fertilziation rates and tissue nutrient levels to maximize growth of flowering plants and characterize the symptoms of nutritional disorders. Measure nutrient uptake through leaves, stems, and roots at different stages of rooting under greenhouse and controlled hydroponic conditions to match fertilizer supply with demand. Quantify the interaction of applied water and fertilizer rates on leaching of different forms of nutrients from propagation media. Identify the fertigation strategies that reduce nutrient leaching while maintaining crop health.

3. Progress Report
Research in this project advances our understanding of how high temperature can inhibit plant growth and flowering, and reduce crop yield. As worldwide temperatures increase, this is an increasingly important area of research. We believe high temperature and drought tolerance are intimately associated as stomatal closure results in an increase in plant temperature during the day. That rise in temperature can result in heat-shock, cell injury and/or decreased flowering, growth and yield. Taken together, information from this project will help us to understand the impact of chronic and short-term high temperature stress on the physiology of growth, flowering, and yield of crops, and develop management strategies for growers to limit high temperature stress to improve yield and ornamental performance. This work may also help identify screening methods to facilitate breeding to increase heat tolerance of flowering of crops. Information on lighting and temperature effects on ornamentals will provide producers with information to promote or inhibit flowering using different lighting treatments to increase the marketability of crops and how temperature interacts with those treatments to affect crop timing and flowering. Lastly, ornamental crops identified as heat tolerant may expand the diversity of ornaments marketed and provide a needed group of ornamentals that can withstand high temperatures and/or have reduced irrigation requirements. We identified 1) the response of photosynthesis of greater than 20 important ornamental crops to light, temperature and carbon dioxide to identify environmental strategies to maximize photosynthesis to increase crop quality and yield, 2) the effects of the environment on efficacy of four plant growth retardants was studied to maximize chemical efficacy to reduce chemical use, 3) what species can survive on rooftops in the Twin cities area (cold northern climate) and the impact of each of those species on a variety of desirable environmental impacts that could reduce building operating costs was tested on a rooftop in Minneapolis, 4) new heat and drought tolerant species (primarily cacti and succulents) were screened that have potential as new floriculture and/or landscape crops that require fewer inputs during production and in the landscape. This project was monitored through periodic email communication and face-to-face meetings 3 times during the year.

4. Accomplishments

Last Modified: 06/24/2017
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