USDA CITRUS BREEDING RESEARCH IN FLORIDA: PAST, PRESENT, AND FUTURE.

Citrus cultivar improvement in the past was done largely through selection of naturally-occurring mutants and occasional desirable zygotic seedlings.
Such selection was the only method available and limited progress was made.
Most new cultivars differed from the original cultivars by one or only a few genes.
Extensive use of genetically similar cultivars in response to market pressures for uniform fruit encouraged monocultures.
The result is large-scale vulnerability to disease or pest problems.

Hybridization was and is still needed to increase the genetic base among citrus scions and rootstocks.
Breeding programs were initiated and progress has been made with both scions and rootstocks.
Scion improvement is being approached through interspecific hybridization among Citrus species as well as through intergeneric hybridization as a long-term approach.
Rootstock breeding has involved intergeneric hybridization since most desirable traits are found outside Citrus. The Florida USDA breeding programs have resulted in improved parental

Symposium on Tropical and Subtropical Fruit Breeding

C.J. Hearn

https://doi.org/10.17660/ActaHortic.1987.196.4