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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Research Project #445148

Research Project: Functional Genomics, Genetic Improvement, and Sustainable Production of Nursery Crops

Location: Floral and Nursery Plants Research

Project Number: 8020-21000-086-000-D
Project Type: In-House Appropriated

Start Date: Apr 14, 2023
End Date: Apr 13, 2028

Objective 1: Develop genomic resources, genetic maps, and gene-trait correlations to provide durable genetic improvement for economically valuable traits such as recurrent flowering, novel floral forms, and disease resistance in hydrangeas, including oakleaf hydrangeas that are native to North America. Sub-Objective 1.A.: Develop gene-trait correlations for double flowers, recurrent flowering, and inflorescence shape in the model nursery crop Hydrangea macrophylla. Sub-Objective 1.B.: Develop gene-trait correlations for powdery mildew resistance in Hydrangea macrophylla and Dichroa febrifuga. Sub-Objective 1.C.: Develop genomic resources for identifying and characterizing native and underutilized nursery crops. Objective 2. Breed or select new cultivars and improved germplasm of novel or underutilized woody landscape plants, such as oakleaf hydrangeas, incense-cedar (Calocedrus decurrens), manzanita (Arctostaphylos species and hybrids), and Osmanthus (Osmanthus species and hybrids) to broaden the diversity of the cultivated landscape and create marketing opportunities for growers. Sub-Objective 2.A.: Generate genetic variation through hybridization, mutation, and ploidy manipulation in native and/or underutilized woody species including, but not limited to, Arctostaphylos, Calocedrus, Hydrangea, and Osmanthus. Sub-Objective 2.B.: Evaluate disease resistance, growth rate, habit, and rooting ability to identify superior germplasm for nursery production and landscape use of native and/or underutilized woody species listed in Sub-Objective 2.A. Objective 3. Improve nursery production practices, including propagation and nutrient inputs for underutilized woody plant taxa such as species listed in Objective 2, to improve nursery input efficiency and facilitate grower adoption of new taxa. Sub-objective 3.A: Develop improved container nursery production practices to decrease nutrient runoff or improve nutrient use efficiency. Sub-objective 3.B: Refine propagation protocols for Calocedrus decurrens and Hamamelis sp.

The research will produce novel genetic variations through hybridization and mutation, and existing genetic variations will be harnessed by collecting and cataloging wild populations of native woody species. Genomic information will be applied to current breeding lines of ornamentals to accelerate the production of high-value nursery crop cultivars. Native and underrepresented woody landscape species improved for product quality and disease resistance will stimulate consumer interest in landscape plants, provide producers with expanded marketing opportunities, and reduce the environmental footprint of nursery production by reducing the need for pesticides. A research-based nursery production protocol for these plants will facilitate adoption, provide additional marketing opportunities for the ornamental horticulture industry, and, ultimately, increase genetic diversity in cultivated landscapes. Increased consumer demand coupled with reduced costs for growers provides a strong foundation for long-term support of the U.S. nursery industry.