I probably put the cart before the horse a bit last time. I want to comment this time on the simpler notion of what colors we see in Clivia flowers and where they come from.
There are three sets of pigments in flowers: reds, oranges, and pinks are generally due to anthocyanin pigments. They are phenolic compounds that are connected to one or more sugar molecules. They include pelargonidin, cyanidin, and delphinidin. the sugar is usually one molecule of glucose, and it is usually connected at the number 3 position on the anthocyanin molecule.
The yellows are usually due to carotenoid pigments. Beta-carotene is one of these that is likely to be familiar to health food enthusiasts. Another is lycopene, the pigment that gives tomatoes their red color. I don't know whether there is ever any lycopene in Clivia flowers or not, but I'd guess that there is not.
Finally, the green color in flowers is due to chlorophyl. We don't think of flowers having chlorophyl, but most have at least a little green here or there.
Red flowers have high concentrations of anthocyanins and often also of carotenoids.
Orange flowers have a bit less anthocyanin, but still have the carotenoids.
Yellow flowers have no anthocyanins, but at least a little carotenoid.
Bronze flowers have chlorophyl which is overlaid with anthocyanin and/or carotenoids.
Green throats in flowers have chlorophyl in the throat but none of the usual carotenoids there.
Peach flowers, it turns out, have almost as much carotenoid as light yellow flowers, but they also have traces of anthocyanins. Peach is just yellow from carotene with a tiny bit of red or orange anthocyanin added.
White flowers, if we ever get those in Clivia, will have little or no carotenoid and no anthocyanin. Pink flowers will have traces of anthocyanins but virtually no carotenoids. I would put the "Appleblossom" group of Clivia in the white to pink category, pending actual chemical analysis of their flowers for pigments.
Dr. Keith Hammett of Aukland, New Zealand, analyzed a series of Clivia types for the pigments in their flower petals. I take the information for this from his article in CLIVIA 8 (published by the Clivia Society in South Africa, 2006), entitled "Pigment Surprise" (pages 39-49).
There is also a nice article in the same issue by Prof. Johan Spies, entitled "Genetic Aspects of Clivia Breeding," CLIVIA 8, pp. 31-38 (2006). I recommend both articles to anyone interested in this topic. You can find the Clivia Society (South Africa) on the web.