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United States Department of Agriculture

Agricultural Research Service

Related Topics


Location: Floral and Nursery Plants Research

2011 Annual Report

1a. Objectives (from AD-416)
Accelerate development of superior Hydrangea germplasm using wide hybridization, molecular markers, and ploidy manipulations. Develop, evaluate, and release improved germplasm of selected nursery crops species, including Hydrangea, Cornus, Clethra, and Styrax. Investigate physiological constraints with transplanting nursery crops and root system changes for better adaptation into production systems. Develop improved nursery production systems with an integrated approach of bio-plastic containers, plant water and nutrient use, and cultural management.

1b. Approach (from AD-416)
Use wide hybridization to improve H. macrophylla. Use molecular markers for studying genetic relationships and creating genetic linkage maps in Hydrangea. Develop a polyploid series in H. macrophylla. Develop, evaluate, and release improved germplasm of Hydrangea, Cornus, Clethra, and Styrax. Evaluate germplasm for nursery production and landscape potential. Determine root growth, root quality and plant performance in non-traditional nursery containers. Determine transplantability and survivability of bare root trees during nursery production and in post harvest landscape settings. Determine the relationship of cyclic irrigation and low nutrient inputs with container-grown ornamental trees. Determine the influence of irrigation and nutrient inputs on bio-based materials for container nursery production.

3. Progress Report
A seedling derived from hybridization of Dichroa febrifuga and Hydrangea macrophylla was selected for propagation and potential commercial evaluation. This seedling has mophead type flower heads, sepals that range in color from pink to purple to dark green, and inflorescences that stay attractive on greenhouse-grown plants for several months. A medium-sized oakleaf hydrangea seedling with large, upright inflorescences was sent to cooperators for evaluation. A Styrax japonicus cultivar was released under the name ‘Spring Showers’. This cultivar, which breaks bud 2 to 3 weeks later in the spring than most Japanese snowbell cultivars, is well-suited for use in areas of the country that frequently have late spring freezes. Six pellets (P 29, P 32, P 37, P 40, P 45, and PNaS) made of biobased plastic resin materials containing various amount of feather fibers, glycerol and other ingredients were evaluated. Roots of pepper failed to grow through a layer of P 29, P 32, P 37, and P 40 pellets; however, roots grew well through P45 pellets. Changes in the surface of pellets were observed using a low temperature scanning electron microscope (LT-SEM). Images indicated that growth of fungal hyphae is the most extensive in P 32, followed by P 29 and P 45 pots. A selection of cold hardy camellias and red-leaved crapemyrtles were planted in new field trials to evaluate for nursery production and landscape potential. A study of nutrient loss via substrate leaching in large nursery containers as influenced by time of daily irrigation and emitter selection was completed. Studies on the time of application of neonicotinoid insecticides for prevention of flatheaded borer attack on Acer rubrum were continued. Prototype bio-based nursery containers were evaluated for structural integrity and subsequent plant growth of selected herbaceous and woody perennials. An evaluation of nutrient input and irrigation management for container grown trees was continued.

4. Accomplishments

Review Publications
Reed, S.M. 2010. ‘Ruby Slippers’ and ‘Munchkin’ Oakleaf Hydrangeas. HortScience. 45(12):1908-1909.

Last Modified: 10/18/2017
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