The Evolution of Citrus Species - Methods to Develop New Sweet Orange Cultivars

Citrus originated before recorded history. Citrus sinensis as the sweet orange began in 1765, though its origin is unknown. Hybridization between Citrus species and subsequent selection may have given rise to the orange. Cultivars likely resulted through selection of naturally occurring mutations over a long history. Selection of natural and induced mu tations and hybridization are methods used to develop new orange cultivars. Hybridization is a more difficult method to accomplish orange cultivar improvement, but the magnitude of trait change is greater than is possible by selection of mutations. 'Ambersweet' is the first recorded orange cultivar developed through hybridization, but other hybrids very similar to the orange have been produced. Organoleptic or taste tests are essential to determine if a hybrid has juice that would be recognized as sweet orange.