2010 Annual Report
1a.Objectives (from AD-416)
Develop improved varieties of peaches and plums for the southeastern United States, and improved clonal and seedling rootstocks for peach and other stone fruits.
1b.Approach (from AD-416)
Superior breeding lines and varieties with unique characters are hybridized, and the best seedlings selected. These selections are tested in multiple years and locations to identify those truly superior to existing varieties in terms of productivity, firmness and quality. These are then named and released for the public to grow.
Parental rootstock lines with superior resistance to peach tree short life and Armillaria root rot as well as other desirable traits, are intercrossed to produce seedlings with the desired characteristics. Extensive testing is used to identify those hybrids which have the requisite combination of disease resistance and horticultural traits for successful commercial use.
Hybridizations were made for the peach breeding programs. Unusually favorable spring weather resulted in excellent fruit set. Peach seedlings for the collaborative moderate chill variety development program were planted into the field for evaluation. Advanced variety selections nearing completion of evaluations were scaled up in anticipation of impending release(s). Numerous very high quality plum and plumcot selections were made throughout the season, many of which were propagated for further trial. It will be necessary to observe their long-term disease resistance before they can be considered for release to the public. Final observations were made on budded trees of flowering peach selection BY94p7706, which has very large red, pink and white blossoms as well as red and green leaves. This selection is slated for release in 2010.
Hand and bee pollinated crosses were made for the rootstock development program.
New peach tree short life, Armillaria root rot, and horticultural trials were established at the Byron location. Previously established grower trials at other locations are continuing to be evaluated. New root-knot nematode trials were established at locations in GA and FL. New rootstock selections were made and propagated for further development. Advanced rootstocks selections nearing completion of evaluations were scaled up in anticipation of impending release(s).
Research conducted under Trust Fund Cooperative Agreement No. 58-6606-9-0217, "Stonefruit Rootstock Development for Resistance to Soilborne Diseases and Nematodes," between ARS and the South Carolina Crop Improvement Association. The development of new rootstocks and management practices for the control of soilborne diseases and nematodes of peach is an urgent need of the southeastern US peach industry. This has become even more apparent with the introduction of Guardian peach rootstock in 1993. Guardian has been widely adopted by the southeastern US peach industry; and though it has provided exceptional resistance to peach tree short life (PTSL), it is highly susceptible to Armillaria root rot (ARR) which has now surpassed PTSL as the primary cause of premature peach tree death. The first group of plum hybrid and plum x peach hybrid rootstock selections bred in this program are approaching completion of their disease resistance and horticultural evaluations. Several items continue to stand out as potential candidates for industry use and one has been proposed as the first release for commercial testing. Evaluations are continuing and the scaling up of materials to support expected release(s) is continuing.
Molecular markers for chilling requirement in peach. Chilling requirement determines where peaches are adapted. In cooperation with Clemson University, molecular markers associated with chilling requirement were identified in peach seedlings from the ARS-Byron breeding program. As the associated genes are identified, it will facilitate breeding for chilling requirement, and enhance understanding of how the chilling process works.
New rootstock for peaches. Premature tree death caused by several soilborne diseases adds significantly to production costs of US peach growers. First interspecific hybrid peach rootstock with broad disease resistance developed by the ARS-Byron rootstock breeding program has been proposed for release. Material has been scaled up for commercial propagation and Invention Disclosure submitted. In research and grower trials on disease infested sites this new rootstock has provided significant improvements in tree performance and longevity compared to current commercial standards.
Beneficial compounds in red-fleshed peaches. Fruit with highly pigmented flesh are thought to have numerous potential health benefits. In cooperation with Texas A&M, compounds contained in red-fleshed peach selections from the ARS-Byron breeding program were found to inhibit reproduction of breast cancer cells in vitro. No high-quality red-fleshed peach selections are available in the US, but advanced breeding selections are approaching commercial quality. These results provide additional incentive to further develop red-fleshed peach material.
Noratto, G., Cisneros-Zevallos, L., Byrne, D.H., Okie, W.R., Porter, W. 2009. Molecular mechanisms involved in the inhibition of MDA-MB-435 breast cancer cells by phenolic acids from the red-flesh peach BY00P6653. Acta Horticulturae. 841:67-72.