Location: Fruit and Tree Nut Research
2022 Annual Report
Objectives
1. Develop new high-chill stone fruit cultivars for main season production areas with improved adaptability, cropping reliability, disease resistance, handling ability, and eating quality. 2. Develop new moderate-chill stone fruit cultivars for early season production areas in the lower coastal plain with improved adaptability, cropping reliability, tree architecture, disease resistance, handling ability, and eating quality. 3. Develop new stone fruit rootstocks with improved disease resistance and a range of vigor control to manage tree size. 4. Determine how the individual genetic components of the pecan genome function collectively to determine priority traits for pecan production such as host-plant resistance to scab disease and floral and fruit development that control alternate-bearing. (NP301, C1 PS1A).
Approach
Elite breeding lines and select varieties with appropriate traits will be hybridized and the best hybrid seedlings selected. These selections will be tested for multiple years in several locations to identify those truly superior to existing commercial varieties in terms of cropping reliability, productivity, fruit size, appearance, firmness and eating quality. These superior selections will then be named and released for use by the commercial peach industry.
Parental root-stock lines with superior resistance to peach-tree short life, Armillaria root rot and commercially important root-knot nematode species will be intercrossed to produce hybrid seedlings with the desired characteristics. Extensive field testing will be utilized to identify those hybrids which have the requisite combination of disease resistance and horticultural traits for successful commercial utilization the southeastern U.S. peach industry. Best selections will be released for commercial utilization.
Progress Report
Under Objective 1. Hand crosses were made for the high-chill peach cultivar development program. Peach seedlings generated in the previous pollination season were planted into the field. Seedlings and advanced selections are being evaluated during the season. Promising advanced selections nearing completion of evaluations were scaled up in anticipation of impending releases. Invention disclosures and release notices of two early-season peach cultivars, intent for commercial use, have been reviewed and approved for patent applications that are currently being reviewed and submitted by the USDA-ARS Office of Technology Transfer. Three licenses have been granted to a commercial nursery to propagate and sell trees of three new peach cultivars. New trials of recent releases are being established under appropriate agreements to continue testing their performance in interested regions.
Under Objective 2. Due to a critical vacancy, no hybridizations were made for the moderate-chill peach cultivar development program. Field evaluation of moderate chill selections were performed by collaborators. Breeding materials are being maintained by another scientist, program technicians and collaborators in the project.
Under Objective 3. Due to a critical vacancy, no hybridizations were made for the rootstock development program, nor were any evaluation trials established. Breeding materials are being maintained by another scientist, program technicians and collaborators in the project.
Accomplishments
1. Marker analysis of U.S. peach cultivars. A large collection of peach cultivars and selections in the USDA-ARS Byron Georgia breeding program have never been analyzed using DNA markers. ARS scientists at Southeastern Fruit and Nut Research Laboratory in Byron, Georgia have genotyped these peach materials and revealed their relatedness using optimally selected DNA markers that were able to distinguish cultivars. The new knowledge facilitates understanding of the materials and optimization of parents in future crosses.
2. Licensing of three new peach cultivars. New and improved peach cultivars remain in high demand by the Southeastern peach industry. Licensing of three new peach cultivars, developed via conventional breeding by ARS scientists at the Southeastern Fruit and Nut Research Laboratory in Byron, Georgia, have been issued by the agency to a commercial nursery and tens of thousands of trees have been ordered by and propagated for commercial growers. Planting trees of the new cultivars with improved characteristics greatly benefits the industry.
Review Publications
Chen, C., Okie, W.R. 2021. Population structure and phylogeny of some United States peach cultivars. Journal of the American Society for Horticultural Science. 147, 1, 1-6. https://doi.org/10.21273/JASHS05117-21.
Chen, C., Rodriguez Bonilla, L., Beckman, T.G. 2022. Assessment of prunus rootstock accessions using chloroplast and nuclear microsatellites. Journal of the American Society for Horticultural Science. 147(2):95-103. https://doi.org/10.21273/JASHS05137-21.
