Dominant and recessive
by Greg Green
Individual genes within a locus are said to be either dominant or recessive. This is noted by a capital letter for a dominant gene and a lower case letter for a recessive gene. Dominant genes have a stronger effect and if only one is present, will win over the recessive gene in that locus.
For example the B gene means the plant will produce big bud, while the b gene means the plant will produce small bud. Since B is dominant a plant with a Bb genotype will produce Big Bud. The B is dominant over the b. In order for a recessive gene to have an effect, both genes must be recessive, so BB is Big Bud, and Bb is Big Bud, but bb will be small bud.