Robertson Old Line Navel Orange Budwood

Citrus sinensis.

Fruit virtually indistinguishable from Washington except for medium-large size, slightly lower quality, and earlier maturity, which is usually ten days to two weeks. While maturing about the same time as Thomson, quality is better and fruit is retained much longer on tree. Because fruit is often borne in tight clusters, its shape is sometimes slightly distorted and exhibits flat contact surfaces.

Tree lacking in vigor (more so than Thomson), small (markedly dwarfed on sour orange rootstock), heat-resistant, precocious, and very prolific.

The heat resistance and associated high-yielding behavior of the Robertson navel orange appear to relate to the fact that, although it blossoms at about the same time as other varieties the young fruits develop more rapidly and pass through the fruit-setting phase earlier. The fruits thus escape the severe dropping associated with the heat and dryness normally characteristic of the later fruit-setting period of other varieties.

Robertson originated as a limb sport in an old Washington navel tree bearing an unusually heavy quantity of fruit.

Rootstocks of accession:  Carrizo citrange.

Season of ripeness at Riverside, California:  December to January.

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