Utilizing the Huanglongbing (HLB) Tolerance Traits in Citrus Relatives to Build Better HLB Tolerant Rootstocks
Posted August 2025
Researchers: Manjul Dutt, Nabil Killiny, Jude Grosser, John Chater, Lamiaa Mahmoud
Contact: Manjul Dutt, UF/IFAS CREC manjul@ufl.edu
Summary:
Several citrus species have enhanced tolerance to huanglongbing (HLB). Some like the Australian lime species (Citrus australasica, C. australis, and C. glauca) are resistant to HLB. Others, such as the C. latipes, have been observed to be highly tolerant of HLB. Our breeding focus has been to utilize the natural tolerance/resistance traits of these species to develop hybrids of HLB-tolerant rootstocks that can better endure HLB and support citrus scions. Hybrids developed with these species and select UF germplasm have demonstrated enhanced tolerance to HLB in preliminary greenhouse studies and limited field evaluations Some hybrids have remained HLB negative as rootstocks even after years of field evaluations. Currently, a select population of these hybrids is being clonally propagated for extensive multi-location field trials. By carefully selecting and breeding citrus varieties with natural HLB tolerance traits, leveraging modern genomic techniques, and conducting thorough field trials, we can develop rootstocks that help citrus trees endure the stresses caused by HLB. Over time, these improved rootstocks could become a crucial component of an integrated strategy to combat HLB and ensure the sustainability of citrus production globally.
Take Home Message:
- HLB-tolerant rootstocks can be produced by breeding with HLB-tolerant citrus relatives.
- Several new rootstocks have demonstrated enhanced tolerance to HLB.
