The term “Wheaten”, in the Rhodesian Ridgeback, is not so much a color as it is a "pattern of color". The general color of a Ridgeback has a wonderful range of shades from light to dark in the brown family - from yellowish to coppery to reddish brown. The areas of the sides of the neck, behind the shoulder and "breeches" are much lighter than the general body colors and the dorsal (topline) and legs (below the stifle and elbows) tend to be darker than the body.
The hair shaft itself is "banded", ie it is lighter at the root and darker at the tip. Of course, on longer haired breeds this is easier to see and gives a "mottled " appearance. As the RR is shorter haired, it is not as evident. The more "wheaten" the dog, the more the "banding" shows on the individual hair shaft. The effect of the lighter color at the roots gives the illusion of a yellowish base. In terms of genetic coat colors, this "banded hair" is called "agouti".
See the page listing NORMAL RR colors to see the fantastic range of beautiful colors in the breed.