Phylogenetic relationships of USDA peach rootstock accessions

Authors: Chen, Chunxian

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/3/2023
Publication Date: 5/3/2023
Citation: Chen, C. 2023. Phylogenetic relationships of USDA peach rootstock accessions. American Society of Horticulture Science Meeting. N/A.

Interpretive Summary:

Technical Abstract: Peach rootstocks serve as the foundation for tree architecture and provide soil-borne disease and pest resistances not possessed in peach scions. Understanding of the phylogenetic relationships among peach rootstock accessions and authentication of their identity can be useful for breeding programs and orchard management. In this report, we used chloroplast and nuclear microsatellites to genotype a collection of peach rootstock accessions, including cultivars, clones, and Prunus species, which are maintained at the U.S. Department of Agriculture stone fruit breeding program at Byron, GA. Phylogenetic analysis with chloroplast microsatellite data revealed that the accessions belonged to four previously defined maternal lineage groups (MLG-1 to -4) and five new ones (MLG-9 to -13). MLG-1 and MLG-2 share the same chloroplast alleles of ‘Chinese Cling’ peach (P. persica) derived scions and American scions and rootstocks related to early European introductions, respectively. MLG-3 included ‘Guardian’ rootstock and its descendants. MLG-4 had a single genotype ‘Okinawa’ that is the maternal parent of ‘Flordaking’. MLG-9 and MLG-11 to -13 included hybrids with different plums (P. salicina, P. cerasifera, P. tomentosa, or P. angustifolia) in their maternal parentage. MLG-10 included hybrids from almond (P. dulcis) in the maternal parentage. The neighbor-joining phylogenetic tree based on nuclear microsatellite genotyping data showed several clusters. Cluster I included only one scion cultivar Elberta from MLG-1. Cluster II, III and V contained peach accessions mostly in MLG-2. Cluster IV and VI included accessions mostly in MLG-3. Cluster VII included most accessions of plum-peach hybrid origin and those found within MLG-13. Cluster VIII were found to be mixed with different plum-peach hybrids and hybrids from other Prunus species, most of which were found in MLG-10, -11 and -12. Most accessions in cluster IX were related to plums in MLG-11 and a few accessions in MLG-9. Overall, the genotyping data and results can be useful for peach rootstock genetics and breeding.