Project Number: 6034-22320-007-08-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2017
End Date: Sep 30, 2020
Assist in screening citrus germplasm for resistance to citrus greening disease by inoculating germplasm with the pathogen responsible for the disease.
We will select five most promising hybrids for generating inarched nursery plants with Kuharske rootstock, Valencia scion and inarched hybrid plants with the help of Brite Leaf Nursery, Florida (year 1). These composite plants will be evaluated for huanglongbing (HLB) tolerance in Fort Pierce, Florida in the greenhouse (no-choice psyllid feeding), in the field (Fort Pierce; natural psyllid feeding), in an organic grove (Uncle Matt’s Organic grove in Clermont, Florida) and in a conventional grove in Florida (to be identified). To inoculate (no-choice in greenhouse), individual plants with flush will be caged with ‘CLas-infected’ Asian citrus psyllid (ACP) for two weeks similar to as described by Hall et al. (2016). Plants not testing positive for the disease after 6 to 8 months will be subjected to inoculation again. The plants will be monitored for years 2 and 3 and HLB disease response analyzed. At this time, we are in the process of generating composite inarched plants with known HLB resistant and tolerant citrus relative accessions: Eremolemon, Finger lime, Microcitrus inodora and Orange jasmine (collaboration with Brite Leaf Nursery). These will be evaluated in the same four scenarios as described before during year 1. The plants will be monitored for three years for HLB disease response. In California, we will generate composite inarched plants using material available in Riverside (under evaluation in University of California (UC) Davis Contained research facility) with a collaborating California nursery (to be identified). The inarched plants will be evaluated in UC Davis contained research facility and in Riverside (in the new BSL3 facility to be built). The plants will also be raised in three locations in CA for horticultural evaluation in the field. [Hall, D. G., U. Albrecht, and K. D. Bowman. 2016. Transmission rates of ‘Ca. Liberibacter asiaticus’ by Asian citrus psyllid are enhanced by the presence and developmental stage of citrus flush. J. Econ. Entomol. 109: 558-563. doi: 10.1093/jee/tow009].