4. For tomato plants, the allele for red fruit color (R) is dominant to the allele for yellow
fruit color (r), and a round shaped fruit (F) is dominant to the allele for pear shaped fruit
(f). One tomato plant that has yellow pear shaped fruit is crossed with a tomato plant that
is heterozygous for red fruit and homozygous for round shaped fruit. What is the
probability that of the F1 offspring will have red pear shaped fruit?
a 50%
b. 38%
c. 0%
d. 28%

The cross between rrff and RrFF does not produce any F1 offspring with the genotype, Rrff, therefore the probability that the F1 offspring will have red pear shaped fruit (Rrff) is: c. 0%

Given the following:

A tomato plant that has a yellow pear shaped fruit will be - rrff

A tomato plant that is a heterozygous red fruit and is h0m0zygous round shaped fruit will be: RrFF

The cross between both parents (rrff × RrFF) is shown in the Punnett Square attached below.

F1 offspring that will have red pear shaped fruit will have the genotype as, Rrff.

Thus, the cross between rrff and RrFF does not produce any F1 offspring with the genotype, Rrff, therefore the probability that the F1 offspring will have red pear shaped fruit (Rrff) is: c. 0%

Learn more about Punnett Square on:

link

The  probability that of the F1 offspring will have red pear shaped fruit 0%.

c. 0%

Explanation:

Given-

Red color (R) is dominant over yellow (r) fruit color

Round shaped (F) is dominant over pear shaped (f) fruit

Yellow pear shaped = rrff

Heterozygous for red fruit and homozygous for round shape = RrFF

Gametes of rrff = rf , rf, rf, rf

Gametes of RrFF = RF, RF, rF, rF

Performing a cross between these gametes would give -

The cross performed is attached as a word file for your reference.

According to the cross,

The probability of red pear shaped fruit is 0%

i believe the answer is c