Skip to main content
ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #419947

Research Project: Genetic Improvement of Citrus for Superior Production, Marketability, and Tolerance to Huanglongbing

Location: Subtropical Insects and Horticulture Research

Title: US-Gallasch: A new citrus rootstock 60 years in the making

Author
item SMITH, MALCOLM - Department Of Agriculture And Fisheries
item GULTZOW, DEBRA - Department Of Agriculture And Fisheries
item NEWMAN, TONI - Department Of Agriculture And Fisheries
item REID, MICHAEL - Department Of Agriculture And Fisheries
item Krueger, Robert
item ROOSE, MIKEAL - University Of California, Riverside
item FEDERICI, CLAIRE - University Of California, Riverside
item Bowman, Kim

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2025
Publication Date: 4/18/2025
Citation: Smith, M.W., Gultzow, D.L., Newman, T.K., Reid, M., Krueger, R., Roose, M.L., Federici, C.T., Bowman, K.D. US-Gallasch: A new citrus rootstock 60 years in the making. HortScience. 60(5): 777–781. 2025. https://doi.org/10.21273/HORTSCI18444-24.
DOI: https://doi.org/10.21273/HORTSCI18444-24

Interpretive Summary: Citrus crops are grown as grafted combinations of a fruiting/scion cultivar growing on a different rootstock cultivar that forms the lower trunk and roots of the tree. Key traits for the rootstock cultivar are disease resistance, tolerance to stressful environmental conditions, graft compatibility with important fruiting cultivars, apomictic seed propagation, good tree size, and induction of good fruit productivity and fruit quality. This manuscript describes one new cultivar that originated at USDA, Indio, California, and was determined by testing in Australia to have desired rootstock characteristics for commercial use in Australia citrus production.

Technical Abstract: US-Gallasch is a new citrus rootstock released by the Queensland Department of Agriculture and Fisheries Australia (QDAF) for wider testing by nurserymen and citrus growers. This hybrid selection was originally produced from a cross made in 1962, in the citrus breeding program of the United States Department of Agriculture (USDA) at Indio, California. The major positive attributes of this rootstock are excellent resistance to Citrus tristeza virus (CTV), salt tolerance, graft union compatibility and induction of moderate tree size, with good productivity and fruit quality. US-Gallasch can be uniformly and efficiently propagated by apomictic seed, showing desirable nursery growth characteristics. The release of this rootstock follows a long path from its original creation, with research on two continents and the revelation of repeated promising parental impacts that may prove useful to future rootstock breeders.