Agriculture Reference
In-Depth Information
Dominant and Recessive:
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.
Modifying Genes:
By breeding we can determine.. Let's say... what the color of
the plant's bud will be, or more importantly, what color the offspring
of two plants is going to look like. The final appearance however will
be the result of more than one gene locus. Plants may have several
color genes for different parts of the plant. A plant's genetic structure
is quite complex.
Partial Dominance:
Now that we have explained the basics of dominant and
recessive, you can move on to the next step.
Some gene loci in plants have more than two possibilities.
These are sometimes referred to as 'partially dominant genes' and are
usually given some type of secondary marker such as B' or B".
