Jenkins, J. A. and G. Mackinney.
Crosses were made between lutescent lines and a number of homozygous carotenoid types: tangerine, beta orange, yellow-apricot and tangerine-apricot. It is only when the lutescent gene is homozygous that it has any effect on chlorophyll and carotenoid content. Homozygous lutescent plants have normal green leaves when young, but as the plants age the leaves turn yellow. Lutescent, when homozygous, has no apparent affect, even on immature fruits, on the content of B-carotene. Lycopene formation, on the other hand, is definitely delayed. Furthermore, there is some indication that the level of lycopene does not reach the level characteristic of normal red-fruited plants. This differential behaviour of lycopene and B-carotene is in keeping with earlier findings that these two carotenoids may vary independently.