Swingle Citrumelo Trifoliate Hybrid Budwood

x Citroncirus spp.

'Duncan' grapefruit x Poncirus trifoliata.

Reported superior attributes of 'Swingle' are being resistant to tristeza and Phytophthora foot rot, blight, cold, and citrus nematode. However, in some cases, trees budded onto 'Swingle' that were infected with 'severe' strains of exocortis or cachexia remained stunted and produced a bud union crease. 'Swingle' is moderatlely salt tolerant but is not adapted to heavy clay soils or calcareous soils. 'Swingle' was observed to be particularly well adapted for use with grapefruits and in some cases 'Lisbon'-type lemons.

These attributes lead 'Swingle' to become the mostly highly utilized rootstock in Florida. However, as older trees on 'Swingle' became available to observe, some limitations became apparent. In addition to those noted above associated with soil conditions, trees on 'Swingle' were observed to decline decline on specific flat woods and ridge soils and when Phytophthora was present in combination with Diaprepes; some apparent incompatibilities with specific scions also appeared. Nonetheless, 'Swingle' is considered one of the 'standard' rootstocks to be considered for planting in many situations or trials.

Rootstocks of accession:  Carrizo citrange, C-35 citrange.

Prepared by the Givaudan Citrus Variety Collection at The University of California Riverside.