2008 Annual Report
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.
This progress falls under National Program (NP) 301, Plant Genetic Resources, Genomics, and Genetic Improvement; Component 3: Genetic Improvement of Crops; Problem Statement 3C: Germplasm Enhancement/Release of Improved Genetic Resources and Varieties.
Hybridizations were made for the peach breeding programs. Late spring frosts reduced fruit set of hybrid fruit. ‘Gulfcrimson’, a moderate-chill peach was introduced as a replacement for ‘June Gold’ in 2007, a year earlier than projected. Significant progress was made in chilling experiments to model dormancy of peach blooms. A manuscript on effects of light on peach flower chilling was drafted.
Hand and bee pollinated crosses were made for the rootstock development program. Spring frost damaged those that were not under shelter. Substantial progress was made in completing the evaluation of the first group of interspecific hybrid selections made in this program. A manuscript on their performance to date and current status was drafted. Initial grower trial of advanced interspecific hybrid rootstock selections was successfully established. New Armillaria, peach tree short life and horticultural trials were established.
This report documents research conducted under a Trust Agreement between ARS and the South Carolina Foundation Seed 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 United States 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 primarily because of its exceptional resistance to peach tree short life (PTSL). However, Guardian 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 trials. Several items stand out as potential candidates for commercial test and release. A manuscript describing their performance in on-station tests and commercial potential has been prepared.
5.Significant Activities that Support Special Target Populations
Okie, W.R. 2008. Nectarine; peach. In: Finn, C.E., Clark, J.R., editors. Register of new fruit and nut cultivars. List 44. HortScience. 43(5):1321-1343.
Okie, W.R., Layne, D.R. 2008. 'Early Augustprince' and 'Augustprince' Peaches. HortScience. 43(5):1600-1602.
Okie, W.R., Layne, D.R. 2008. 'Scarletprince' and 'Julyprince' Peaches. HortScience. 43(5):1603-1605.
Beckman, T.G. 2008. Nursery performance of peach seedling rootstocks. Journal of American Pomological Society. 62(2):46-51.
Beckman, T.G., Krewer, G.W., Chaparro, J.X., Sherman, W.B. 2008. Potential of non-melting flesh peaches for the early season fresh market. Journal of American Pomological Society. 62(2):52-57.