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United States Department of Agriculture

Agricultural Research Service

Related Topics


Location: Application Technology Research

2011 Annual Report

1a. Objectives (from AD-416)
Sustainability of the $4.22 billion commercial floriculture industry in the U.S. is being seriously challenged due to high energy costs. Considerable grower interest exists in producing winter and spring crops at lower temperatures to reduce heating costs. However, adoption of this practice may lengthen the production cycle thereby decreasing profits realized from growing at a lower temperature. We propose an efficient screening procedure to identify begonia accessions from a large germplasm pool that tolerate reduced temperature production. A well established preproduction screening procedure on seedlings or rooted cuttings will enable systematic evaluation of a larger number of plant accessions prior to conducting more expensive production evaluations with larger plants.

1b. Approach (from AD-416)
We will evaluate plants at plug stage (rooted cuttings or seedlings) for their physiological growth response at lower temperatures. Rooted cuttings, rather than seeds, are to be used for many accessions because in those accessions, seed propagation is slow. Replication will be 15 begonia plants per accession. Using non-contact, non-destructive measurement methods, we will be able to evaluate a larger number of accessions at several distinct growth temperatures. Begonia will be generated and provided by the Ornamental Plant Germplasm Center (OPGC) (Columbus, Ohio). Some accessions in the OPGC collection have reported tolerance to cooler temperatures (e.g. Begonia grandis) and will be evaluated first. Also included in this research are species and cultivars of commercial importance including B. cucullata, a parent of many commercially important hybrid Semperflorens, and commercial cultivars for comparison include ‘Big’ series from Benary, ‘Dragon Wing’ from PanAmerican, and ‘Volumia’ from Syngenta. At the conclusion of the study, all data will be entered into the USDA National Plant Germplasm System Germplasm Resources Information Network (GRIN) and be made publicly available. Small plants (plugs) of 50 begonia accessions will be grown in growth chambers set to a range of temperatures (3ºC increments, 3 steps, 15°C, 18°C, and 21°C) for a period of two to three weeks. This represents “normal” or recommended temperatures for greenhouse production for begonia, and 3ºC and 6ºC cooler than recommended. Photoperiod of the growing environment will be selected following a literature review to avoid its effects on flowering. After the two to three weeks time period, non-destructive measures of whole plant CO2 gas-exchange (photosynthesis and respiration), chlorophyll fluorescence, and number of leaves added during this period will be made at those growth temperatures. Two of the best and two of the worst performing accessions at plug stage will be grown to maturity under the three growth temperatures. Their harvest quality such as foliage width, foliage height, time to bloom, bloom duration, time to marketability will be correlated with the early indicators. During that growth period, leaf unfolding will be calculated. After that period, non-destructive measures of whole plant CO2 gas-exchange (photosynthesis and respiration) and chlorophyll fluorescence will be made at those growth temperatures. The three performance measures will be analyzed separately in a randomized block design and as an index using all three measures weighted by the reciprocal of their variance.

3. Progress Report
No progress was made on this project due to the September 2010 tornado that destroyed the cooperator's place of research. This research addresses ARS parent project objective 2A: Evaluate the use of non-destructive sensor technology to measure and predict the impact of biotic and abiotic stresses in ornamental crops. Progress on this project, such that it was, was monitored via phone and e-mail.

4. Accomplishments

Last Modified: 10/17/2017
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