Early-season Sweet Oranges and Grapefruit with Improved Tolerance to Huanglongbing
Posted August 2025
Researchers: Manjul Dutt, Gary England, Sheetal Ramekar
Contact: Manjul Dutt, UF/IFAS CREC manjul@ufl.edu
Summary:
We have recently identified several early-season selections that better tolerate huanglongbing (HLB) than other earlies. This project has led to the Citrus Research and Field Trial (CRAFT) Foundation recommendations of two selections: R20-T30 (a ‘Parson Brown’ type) and R21-T36 (a ‘Hamlin’ type), and they are available for evaluation by the stakeholders. A new ‘Flame’ grapefruit-derived bud sport that better tolerates HLB has also been identified. Named the Lennon Flame, the bud sport produces later maturing fruit (2-3 weeks later than the parent) and is notably healthier, with lush green leaves and better fruit quality. This selection is also available in the Division of Plant Industry (DPI) repository for propagation. Some selections sourced from the Carney Orange 3 are currently being evaluated in the field, and several are showing healthy growth with very low HLB titers. These selections are being grown without any IPC covers to assess their response to HLB in these young trees. A few of these selections are also being propagated for more extensive replicated field evaluations to confirm our preliminary observations.
Take Home Message:
- Newer selections have enhanced tolerance to HLB and are being propagated for multi-location field trials to confirm HLB tolerance.
