2011 Annual Report
2. To identify plant traits which impart resistance to the psyllid, traits that could be used to develop commercial citrus varieties with psyllid resistance for the purpose of reducing incidence of huanglongbing disease.
Citrus germplasm (87 genotypes including citrus relatives) was assessed in a field study for resistance to natural South Florida populations of the psyllid. The majority of genotypes surveyed hosted all three life stages of the psyllid; however, there were significant differences among genotypes in infestation levels of eggs, nymphs and adults. Although not completely avoided, very low levels of the psyllid were found on two surveyed genotypes of Poncirus trifoliata, Simmon’s trifoliate and Little-Leaf. Poncirus trifoliata readily forms hybrids with other citrus germplasm, is commonly incorporated into rootstock varieties, and has been used in breeding advance scion material. The identification of partial resistance in P. trifoliata to the psyllid may prove useful in future citrus breeding efforts aimed at reducing the incidence and spread of huanglongbing.