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United States Department of Agriculture

Agricultural Research Service

Research Project: Using Lighting Technologies and Genetics to Improve Growth and Flowering of Floriculture Crops

Location: Application Technology Research Unit

Project Number: 3607-21000-017-09
Project Type: Specific Cooperative Agreement

Start Date: Sep 18, 2013
End Date: Aug 14, 2018

Objective:
1. To use new lighting technologies, especially light-emitting diodes (LEDs), to understand how ornamental plants grow and acclimate to different light environments. 2. a) To develop molecular markers for two interspecific hybrid petunia populations, P. axillaris x P. exserta and P. axillaris x P. integrifoli; b) To develop genetic linkage maps for the interspecific hybrid populations; and c) To use these populations and markers to develop molecular markers for early flowering traits.

Approach:
A series of experiments will be performed with herbaceous annuals, including popular bedding plants, to quantify how plants grow and acclimate to different light intensity and light quality treatments. Experiments will be performed in chambers that contain blue, green, and red LEDs, and additional colors of light may be added depending on results and development of other LED colors (e.g., far red). All other environmental parameters will be closely monitored and controlled to ensure that results can be attributed to the lighting treatments and are not confounded with other parameters such as temperature. In some experiments, plants will be grown from seed or cuttings for 4 to 5 weeks under various light quality treatments, and plant growth characteristics such as leaf area, height, and fresh weight will be collected. In some cases, plants will subsequently be grown in research greenhouses to determine if there are any carry-over effects from the light quality treatments delivered to propagules on the plants at flowering. In order to employ molecular breeding techniques, baseline genomic data and genetic linkage maps need to be generated to allow for development of specific molecular markers for traits of interest, such as the stakeholder-identified trait of earlier flowering. Through this project, we will sequence the transcriptomes of three Petunia species, utilizing a variety of tissues and stages of development, to identify SSR and SNP markers across species. These markers will be utilized to genotype 300 recombinant inbred lines (RILs) from the interspecific hybrid populations P. axillaris x P. exserta and P. integrifolia x P. axillaris for the development of genetic linkage maps. We will generate approximately 3000 SNP markers for allelic discrimination and mapping in P. integrifolia x P. axillaris and P. axillaris x P. exserta RIL populations. The two RIL populations will be grown in several greenhouse trials and data will be collected on crop timing and quality traits. These data will be used for quantitative trait locus (QTL) analysis. Following the QTL analysis, we will select individuals from the RIL populations exhibiting the extremes of the phenotypic range for development rate as parents for test crosses within the RIL populations to evaluate the utility of the developed markers and for RNA sequencing to identify candidate gene that may be involved in the control of development rate.

Last Modified: 4/21/2014
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