What are the genotypes of the parents and offspring, if from crossing a tomato with globular yellow fruits

What are the genotypes of the parents and offspring, if from crossing a tomato with globular yellow fruits with a tomato producing pear-shaped red fruits, 25% of individuals with globular yellow fruits were obtained, 25% – with globular red, 25% – with pear-shaped yellow fruits and 25% – with pear-shaped red fruits?

This splitting in the offspring, corresponding to a ratio of 1: 1: 1: 1, is characteristic of the so-called analyzing type of crossing, when a heterozygote is crossed with a homozygote for a recessive gene. Since the problem considers 2 traits, we should talk about crossing a heterozygote with a recessive digomozygote.

Let’s designate the gene that causes the yellow color of tomato fruits as K, then the gene for the red color of the fruits of this plant will be designated as k. Let’s designate the gene for the round shape of tomatoes as L, then the gene for the pear shape will be l.

Tomatoes with a globular yellow fruit are KkLl. They are capable of producing four types of germ cells – kl, KL, kL, Kl.

Tomatoes with a red pear-shaped fruit are kkll, they produce the same type of germ cells – kl.

As a result of crossing tomatoes with each other, we get offspring, including the options:

tomatoes with a pear-shaped red fruit (kkll) – 25%;

tomatoes with a yellow spherical fruit (KkLl) – 25%;

tomatoes with red spherical fruit (kkLl) – 25%;

tomatoes with a yellow pear-shaped fruit (Kkll) – 25%.

An equal splitting of 1: 1: 1: 1 will also work if the red color of tomato fruits is taken as dominant, and the parent plants are designated as kkLl (yellow globular tomatoes, gametes – kL and kl) and Kkll (red pear-shaped tomatoes, gametes – Kl and kl).

Answer: 1) diheterozygote (KkLl) + recessive dihomozygote (kkll); or – 2) heterozygote for the first trait and homozygote for the recessive second (Kkll) + homozygote for the recessive first trait and heterozygote for the second (kkLl).