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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

2011 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
During FY11, progress was made on all three objectives, which fall under NP301.

Selections were made from mature flowering cherry hybrids that had been growing in the field for 7-15 years. Plants were propagated for replicated trials in our nurseries and to send to cooperators. A study to examine DNA fingerprints of historic Yoshino cherries at the Tidal Basin was begun.

Selections of mature crapemyrtles were also made based on flower color, habit, and flowering time. Crapemyrtle selections were propagated for replicated field evaluation, and to initiate a study to determine the inheritance of early flowering. Crosses were made among early-flowering hybrids in order to develop early flowering cultivars.

A propagation study in box huckleberry was initiated in order to determine the best time of the year to take cuttings of this species. Seeds from open-pollinated crosses were harvested, and seeds collected last year were successfully germinated.

Controlled interspecific hybridizations in Cercis and Corylopsis were conducted in order to create novel or sterile interploid hybrids (Corylopsis) or to combine traits of interest (Cercis). Measurements of ploidy among species and selections in both these genera were made using the flow cytometer.

Selections of crapemyrtle, Picrasma, and flowering cherry were established in tissue culture and treated with oryzalin to create tetraploid plants. Tetraploids were confirmed by flow cytometry, and will be multiplied and hardened off for use in breeding.


4.Accomplishments
1. Release of camellia ‘Anacostia’. The introduction of new woody ornamental plants is one of the driving forces behind the sustained growth of the ornamental horticulture industry. The introduction of new cultivars addresses the need for new landscape plants that are disease and pest resistant and of superior ornamental value. ARS researchers in Washington, DC released Camellia ‘Anacostia’ in 2010. This plant was selected for its abundant, large, semi-double pink flowers; dark glossy evergreen foliage; rounded and relatively compact growth habit; and increased cold hardiness. It is well-suited for use as a specimen plant, hedge or screen, foundation plant, or mass planting. ‘Anacostia’ is currently being propagated by several wholesale growers and has limited wholesale availability.

2. Release of Loropetalum ‘Snow Panda’. The introduction of new woody ornamental plants is one of the driving forces behind the sustained growth of the ornamental horticulture industry. The introduction of new cultivars addresses the need for new landscape plants that are disease and pest resistant and of superior ornamental value. ARS researchers in Washington, DC released a new variety of Chinese fringe flower (Loropetalum chinense) ‘Snow Panda’ in 2011. This plant was selected for its abundant white fringe-like flowers, medium-green foliage, and loosely vase-shaped habit. It is well-suited for use as an evergreen hedge or screen, foundation plant, container plant, or espalier. ‘Snow Panda’ is currently being propagated by a wholesale nursery cooperator for availability in 2012.


Review Publications
Pooler, M.R. 2011. 'Anacostia' Camellia. HortScience. 46:139-140.

Last Modified: 8/22/2014
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