Sometimes there can be more than one desirable gene. you are going to give two plants of your favorite tomato variety to a friend, and you want both of them to have the desirable allele at each of two genes. at gene one, you know the parents are both heterozygotes; at gene two, the mother is heterozygous and the father is homozygous for the desirable allele. what is the probability of any given seed being heterozygous for both genes?

1/4 or 25%

Explanation:

This question illustrates a cross involving two genes coding for two desirable traits in a tomato plant. Let's assume that the desirable traits are coded for by the dominant alleles B and C.

According to the question, the female parent is heterozygous for both genes B and C i.e. will have a genotype, BbCc while the father is heterozygous for Gene B and homozygous for the desirable trait in gene C I.e. will have a genotype, BbCC

N.B: Dominant alleles B and C are responsible for the desirable traits.

In a cross between parents: BbCc and BbCC, each parent will produce gametes according to Mendel's law of segregation. The possible gamete combinations are:

BbCc - BC, Bc, bC and bc

BbCC - BC, BC, bC and bC

Using these gametes in a punnet square (see attached image), 16 possible seed offsprings will be produced. However, out of the 16 possible offsprings, 4 of them will likely be heterozygous for both genes i.e. possess a genotype, BbCC.

Hence, 4/16 = 1/4 is the probability of a given seed to be heterozygous for both genes.

it will increase due to the time span

"do a testcross with a homozygous recessive plant."