Corrugated Thomson navel orange

Citrus sinensis (L.) Osbeck

CRC 1381

PI 539562

Photos by Toni Siebert, CVC. Photo rights.

Source: Received as a live tree from A.D. Shamel, USDA, 1923.

Parentage/origins: Apparently a limb sport of unknown origin.

Rootstocks of accession: Carrizo citrange, C-35 citrange

Season of ripeness at Riverside: November to January

Notes and observations:

EMN, 1985: Tree furnished by A.D. Shamel. This is a limb sport. This accession had exocortis, removed by shoot tip grafting.

EMN, 11/1988: Only 2 fruits, both small & green, may be off-bloom. Entire fruit rind surface is very corrigated.

EMN, 12/14/1989: Light crop this season. Fruit rind is deeply corrugated with the raised ridges rough and darker orange color than the valleys which are very smooth like the rind of ordinary Thomson. Internal-flesh coarse like Thomson. Typical navel orange flavor. Tree 7 had a large center non-corrigated limb (probably a regressive chimera) which I removed. Fruit on this limb seemed to be typical Thomson. Next door limb may also have lost chimera for corrugation, but there was no fruit on it, so I left it. Watch & remove if needed. This is an interesting chimera, almost strange enough to put through clean-up and release as an ornamental, but probably not quite.

The fruit has raised, rough ridges on the rind that are darker orange than the valleys which are very smooth like the rind of an ordinary Thomson navel.  Internally the fruit is the same flavor and texture of the standard Thomson navel.  Occasionally the tree grows limbs that are non-corrugated, probably a regressive chimera.  Corrugated Thomson would make an appealing ornamental.

Availability: Not commercially available in California.

USDA Germplasm Resources Information Network page for Corrugated Thomson navel orange