In pea plants, the allele for yellow seeds [tex]$(Y)$[/tex] is dominant and the allele for green seeds [tex]$(y)$[/tex] is recessive. Two plants with the following genotypes are crossed:
[tex]$
Yy \times Yy
$[/tex]

What ratio of yellow seeds to green seeds should you expect in the offspring?

A. 3:1
B. [tex]$4:0$[/tex]
C. 2:2
D. [tex]$1:3$[/tex]



Answer :

Let's analyze the cross between two pea plants and determine the expected ratio of yellow seeds to green seeds in the offspring.

The genotypes of the parent plants are [tex]\( YY \)[/tex] and [tex]\( Yy \)[/tex]. Here, [tex]\( Y \)[/tex] represents the dominant yellow allele and [tex]\( y \)[/tex] represents the recessive green allele.

When we cross these two plants, we can use a Punnett square to visualize the genotypic combinations of the offspring.

The Punnett square for this cross is as follows:

[tex]\[ \begin{array}{c|c|c} & Y & Y \\ \hline Y & YY & YY \\ \hline y & Yy & Yy \\ \end{array} \][/tex]

From the Punnett square, we obtain the following genotypes for the offspring:
- [tex]\( YY \)[/tex]
- [tex]\( YY \)[/tex]
- [tex]\( Yy \)[/tex]
- [tex]\( Yy \)[/tex]

Now, let's count the number of each genotype:
- Two offspring have the genotype [tex]\( YY \)[/tex].
- Two offspring have the genotype [tex]\( Yy \)[/tex].

Both [tex]\( YY \)[/tex] and [tex]\( Yy \)[/tex] result in yellow seeds because the yellow allele [tex]\( Y \)[/tex] is dominant.

Therefore, all four offspring will have yellow seeds.

As a result, the ratio of yellow seeds to green seeds in the offspring is [tex]\( 4:0 \)[/tex].

Thus, the correct answer is:

B. [tex]\( 4 : 0 \)[/tex]