Location: Fruit and Tree Nut Research
2021 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.
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
Objective 1. Hybridizations were made for the high-chill peach variety development program. Peach seedlings generated in the 2020 pollination season were planted into the field. Seedlings and advanced selections are being evaluated by ARS scientists in Byron, Georgia, during the season. Promising advanced selections nearing completion of evaluations were scaled up in anticipation of impending releases. Two invention disclosures of peach cultivars, intent for commercial use, were submitted by ARS scientists in Byron, Georgia. New trials of recent releases are being established under Material Transfer/Evaluation Agreements to continue testing their performance in different regions.
Objective 2. Hybridizations were made for the moderate-chill peach variety development program. Fruit set was good in plastic covered greenhouse and in field under frost protection shelters. Hybridizations were also made in the field and fruit set was also good, heaters were set up in the orchard to help with frost damage. Some moderate chill hybrids planted by ARS scientists in Byron, Georgia, produced fruits for the first time and seed was collected.
Objective 3. Hand pollinated and bee mediated crosses were made for the rootstock development program. New Armillaria root rot and graft compatibility trials were established at the Byron, Georgia location. Previously established grower trials at other locations are continuing to be evaluated.
Accomplishments
1. DNA markers reveal parentages of historical peach cultivars. Pedigrees of well-known ‘Elberta’ and other historical peach cultivars in the U.S. are conjectural. DNA markers can be used to authenticate pedigrees and/or parentages. ARS scientists in Byron, Georgia, have used DNA marker data of forty-eight historical peach cultivars in the U.S. to validate some parentages and their genetic relationships.
Review Publications
Chen, C., Okie, W.R. 2021. Genetic relationship and parentages of historical peaches revealed by microsatellite markers. Tree Genetics and Genomes. 17/35. https://doi.org/10.1007/s11295-021-01517-8.
Chen, C. 2021. Peach cultivar releases and fruit trait distribution in the USDA-ARS Byron program. Acta Horticulturae. 1304/29-35. https://doi.org/10.17660/ActaHortic.2021.1304.4.
Chen, C. 2021. Genotyping variability of computationally categorized peach microsatellite markers. Acta Horticulturae. 1304/107-112. https://doi.org/10.17660/ActaHortic.2021.1304.17.
