Bioscience in brief
Plant genetics and crop breeding
What is the difference between yellow and white maize?
The occurrence of yellow or white colour of maize kernels is controlled by a single gene.
- Why do some maize ears have so many different coloured grains? Each maize grain is actually a different individual (the seed of a new plant) with a unique mix of genes inherited from its parents.
The difference between yellow and white maize grains is due to the colour of the nutritive tissue that surrounds the embryo in the seed, called the endosperm.
Endosperm colour in maize is controlled by a single gene. The presence of a single (dominant) Y allele leads to the production of carotenoid pigments in the endosperm and results in yellow seeds. White maize seeds occur when two recessive y alleles are present: carotenoids are not produced and the endosperm is white.
The colour of the endosperm may be masked if the outer layer surrounding it (called the aleurone) is also pigmented. The aleurone may be colourless (as in white and yellow maize), purple or red.