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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETICS, GENETIC RESOURCE EVALUATION, AND GENETIC IMPROVEMENT OF LANDSCAPE TREES AND SHRUBS

Location: Floral and Nursery Plants Research Unit

2009 Annual Report


1a.Objectives (from AD-416)
The overall objective of this project is to breed, evaluate, select, and release improved landscape trees and shrubs that are disease and pest resistant, tolerant of environmental stresses, are not invasive, and have superior ornamental value. This objective is achieved by genetically characterizing and evaluating the horticultural merit and stress resistance contained in germplasm and advanced selections of Cercis, Lagerstroemia, and Prunus (primary genera), as well as historical or exploratory genera such as Corylopsis, Deutzia, Ilex, Gaylussacia, Syringa, and Viburnum (secondary genera); developing new or improved genetic marker systems for assessing genetic diversity and accelerating genetic improvement of these genera; incorporating improved disease and stress resistance and ornamental traits into this germplasm using traditional and new breeding methodologies; and transferring superior landscape plant cultivars and germplasm to end users. This research will result in new cultivars of landscape trees and shrubs that have value to the nursery and landscape industries; germplasm that has been evaluated or enhanced for various traits; and technology on molecular markers, gene manipulation, and wide hybridization.


1b.Approach (from AD-416)
Conduct comprehensive breeding programs by genetically characterizing and evaluating the horticultural merit and stress resistance contained in germplasm and advanced selections of Cercis, Lagerstroemia, and Prunus (primary genera), as well as historical or exploratory genera such as Corylopsis, Deutzia, Ilex, Gaylussacia, Syringa, and Viburnum (secondary genera); developing new or improved genetic marker systems for assessing genetic diversity and accelerating genetic improvement of these genera; incorporating improved disease and stress resistance and ornamental traits into this germplasm using traditional and new breeding methodologies; and transferring superior landscape plant cultivars and germplasm to end users.


3.Progress Report
Redbud (Cercis) cultivars were collected and planted out to serve as references or germplasm as part of the Cercis breeding program. Molecular genetic diversity and genetic relationships of these cultivars were analyzed using SSR markers. Selections of viburnum, redbud, crapemyrtle, flowering cherry, and lilac were made and propagated for replicated field planting. Several remaining Pyracantha accessions and intergeneric hybrids were propagated in order to rejuvenate and save this germplasm. Controlled pollinations were made in flowering cherry, redbud, and crapemyrtle, and seeds were harvested and sown. Open-pollinated seeds from box huckleberry, which represent significant recombination in this species, were collected from diverse accessions. Selections of several taxa (Picrasma, Catalpa, Cercis, Prunus, Lagerstroemia) were established or treated in-vitro with a mitotic inhibitor to induce chromosome doubling, resulting in tetraploids of Cercis and Prunus. Ongoing and new propagation projects were set up in new greenhouse facilities that were completed in May 2009.


6.Technology Transfer

Number of Active CRADAs1
Number of the New/Active MTAs (providing only)4

Review Publications
Ma, H., Pooler, M.R., Griesbach, R.J. 2009. Anthocyanin regulatory/structural gene expression in Phalaenopsis. Journal of the American Society for Horticultural Science. 134:88-96.

Last Modified: 10/1/2014
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