2012 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 fertilization 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.
Managing Temperature in Greenhouses for Energy Conservation: A second experiment was conducted to quantify the effect of temperature on crop timing and plant quality for a range of popular bedding plant species. Approximately 20 different crops were grown in our research greenhouses at constant temperatures ranging from 57 to 79 °F, and flowering time and plant quality parameters were recorded. These results are being combined with a previous experimental replicate. Currently, data is being analyzed and generating equations that predict flowering time within the temperature range studied. These equations allow for extrapolation beyond this temperature range to estimate the species-specific base temperature and in some instances, maximum temperature. This information will be added to the Virtual Grower program.
Another series of experiments was performed to compare the effect of starting plant size on crop timing. Five different crops were grown from two different transplant sizes and were grown at either 63 or 73 °F. This will provide information on how the maturity (or size) of the transplant influences crop timing. A simple analysis is being performed comparing production costs when starting with the two transplant sizes and when crops are grown at the two temperatures.
Genetic Approaches to Improving Energy-Efficiency of Petunia Production: Researchers developed two populations of recombinant inbred lines derived from interspecific petunia crosses. Approximately 200 inbred lines have been developed for the Petunia integrifolia × Petunia axillaris (the species that were originally hybridized to breed the garden petunia, Petunia hybrida) population and, in collaboration with an industry partner, developed approximately 300 lines from a Petunia axillaris × Petunia exserta population. These populations will serve as an ‘eternal’ resource that researchers and industry breeders can utilize to understand the genetics of traits controlling crop timing and crop quality, and for breeding to improve these traits of interest. The Petunia integrifolia × Petunia axillaris recombinant inbred lines were evaluated for development rate, time to flower, and many crop quality parameters. From this, the fastest and slowest developing lines were identified. These lines will be used to evaluate the utility of the molecular markers that were previously identified for development rate to breed for faster development under cool temperatures.
Participating members of the “North South Initiative Team” (The Floriculture Research Alliance) wrote a six-part series of articles based on research supported by the USDA Floriculture and Nursery Research Initiative as well as private horticulture companies and granting agencies. The articles appeared in Greenhouse Product News magazine, with each print version reaching 20,000 people in the U.S. greenhouse industry, and many more though its website. In addition, research-based information was presented in person to growers at meetings throughout the U.S.
The same team developed FlowersOnTime, which is a decision-support tool that predicts how a modification in temperature influences flowering time for a grower’s existing production schedule. The program is an Excel spreadsheet and can be downloaded under the “Grower resources” tab at the Floriculture Research Alliance website. This is a faster way of evaluating how temperature alone influences development of crops compared to Virtual Grower.
This project relates to two sub-objectives of the parent project. Sub-objective 1a: Elucidate the optimal tissue concentration of P and B in different light environments for major production species and how their susceptibility to foliar and root pathogens are influenced by nutrient status and light; and sub-objective 2b: Improve the Virtual Grower software model to enable growers to optimize their production systems by making more informed economic decisions about energy use, plant growth, and scheduling to meet premium market windows. Each 12-month milestone adds 6 to 8 new species, and this project will assist in meeting that goal. Additionally, features such as supplemental lighting, water use, nutrient use, can be added and improved, and additional model validation will be accomplished. It is planned that every 12 months, an additional version will be publicly released.