Location: Floral and Nursery Plants Research2010 Annual Report
1a. Objectives (from AD-416)
The primary objective of this work is to develop seedless cultivars of invasive or potentially invasive nursery crops. Secondary objectives are to develop new technologies and methods to facilitate theses efforts and to further enhance pest resistance, adaptability, and commercial potential of these crops.
1b. Approach (from AD-416)
These efforts will focus on traditional breeding methods to develop seedless cultivars. Tetraploid clones will be identified or developed and then hybridized with diploids to create triploids. Additional approaches will include mutation breeding, wide hybridization and breeding for double flowers lacking pistils. Resulting progeny will be assessed for fertility and commercial merit. Target crops will include: amur maple (Acer ginnala), barberry (Berberis spp.), catalpa (Catalpa spp.), elaeagnus (Elaeagnus spp.), flowering crabapple (Malus spp.), flowering pear (Pyrus spp.), lace-bark elm (Ulmus parvifolia), miscanthus (Miscanthus spp.), mimosa (Albizia julibrissin), Norway maple (Acer platanoides), privet (Ligustrum spp.), spirea (Spiraea spp.), St. Johnswort (Hypericum spp.), and winged euonymus (Euonymus alatus).
3. Progress Report
The objective of this agreement is to develop seedless cultivars of invasive, but commercially important, nursery crops. Ongoing efforts have been successful in building germplasm collections and developing tetraploid clones of the principal taxa of interest. As these tetraploids reach maturity, interploid crosses have been initiated resulting in triploid hybrids which are then evaluated for fertility and commercial characteristics. Non-invasive cultivars of these species provide environmentally friendly and commercially desirable alternatives to older, invasive forms of these plants. Additional benefits from these seedless plants include elimination of nuisance fruits, reduced pollen-induced allergies, and improved flowering and re-blooming characteristics. These new products will be made available to the nursery industry and will ultimately benefit the environment and the general public. Progress has been made in the development of tetraploid and triploid plants in diverse genera of woody taxa. We have been successful in developing tetraploids of Acer tartaricum subsp. ginnala (amur maple), Albizia julibrissin (mimosa), Berberis thunbergii (Japanese barberry), Cytisus spp. (Scotch broom), Koelreuteria paniculata (goldenraintree), and Ulmus parvifolia (lacebark elm). We have also initiated Acer platanoides (Norway maple) in tissue culture in efforts to develop a system for polyploidy induction. Once these plants reach reproductive age, we will complete interploid crosses to develop triploids. In addition to tetraploids, we have successfully developed triploid forms of Campsis sp. (trumpet vine), Elaeagnus spp., Euonymus alatus (winged euonymus), Hypericum androsaemum (tutsan St. Johnswort), Ligustrum spp. (privet), Miscanthus spp. (maiden grass), Pyrus spp. (flowering pear), and Spiraea japonica (Japanese spiraea). These plants are currently being evaluated for commercial merit and fertility. An extensive study was completed that documented that triploid H. androsaemum had no detectable female fertility. Three triploid hybrids have been selected for commercial release. Initial studies indicated that triploid Campsis sp. and tetraploid A. tartaricum subsp. ginnala are also highly infertile, if not sterile. Triploid Miscanthus clones are currently being evaluated for fertility in replicated studies. Research activities conducted under this agreement were monitored by regular email communication, submission of reports by the cooperator, and by in-person communication at scientific and stakeholder meetings.