A pea plant having flat yellow pods (FFYY) is crossed with a pea plant having constricted green pods (ffyy). Show the phenotype and genotype of F1 and F2 generations.

Parental Cross:

• Parent 1: Flat yellow pods (FFYY)
• Parent 2: Constricted green pods (ffyy)

Step 1: F1 Generation

The F1 generation is the result of crossing the two parental plants.

• Flat pod shape (F) is dominant over constricted pod shape (f).
• Yellow pod color (Y) is dominant over green pod color (y).

So, the genotype of the parents are:

• Parent 1 (FFYY): Homozygous dominant for both traits.
• Parent 2 (ffyy): Homozygous recessive for both traits.

When we cross them (FFYY × ffyy), the F1 generation will inherit one allele from each parent for both traits. Thus, the offspring will have the following genotype:

• F1 genotype: FfYy (heterozygous for both traits)

Since both the F and Y alleles are dominant, the phenotype of the F1 generation will be flat yellow pods.

• F1 Phenotype: Flat yellow pods

Step 2: F2 Generation

Now, let’s cross two F1 individuals (FfYy × FfYy) to produce the F2 generation. We can use a Punnett square to figure out the genotypes and phenotypes of the F2 generation.

Step 2a: Punnett Square for FfYy × FfYy

For each trait, we have two alleles that can combine:

• F x F gives FF, Ff, or ff for the pod shape.
• Y x y gives YY, Yy, or yy for the pod color.

So, let’s construct a Punnett square for both traits combined:

	FY	Fy	fY	fy
FY	FFYY	FFYy	FfYY	FfYy
Fy	FFYy	FFyy	FfYy	Ffyy
fY	FfYY	FfYy	ffYY	ffYy
fy	FfYy	Ffyy	ffYy	ffyy

Step 2b: Genotypic Ratios

Now, let’s calculate the genotypic ratio for the F2 generation:

• FFYY: 1
• FFYy: 2
• FfYY: 2
• FfYy: 4
• FFyy: 1
• Ffyy: 2
• ffYY: 1
• ffYy: 2
• ffyy: 1

Step 2c: Phenotypic Ratios

Next, let’s determine the phenotypes:

• Flat pods (F-) dominate over constricted pods (ff).
• Yellow pods (Y-) dominate over green pods (yy).

So, for the F2 generation:

• Any individual with at least one F allele will have flat pods.
• Any individual with at least one Y allele will have yellow pods.

Phenotypic Summary:

• Flat yellow pods (F- Y-): These plants will have either FFYY, FFYy, FfYY, or FfYy genotypes.
• Flat green pods (F- yy): These plants will have genotypes FFyy or Ffyy.
• Constricted yellow pods (ff Y-): These plants will have genotypes ffYY or ffYy.
• Constricted green pods (ff yy): These plants will have genotype ffyy.

Phenotypic ratio:

• Flat yellow pods: 9/16
• Flat green pods: 3/16
• Constricted yellow pods: 3/16
• Constricted green pods: 1/16

Final Results:

• F1 Generation Genotype: FfYy

• F1 Generation Phenotype: Flat yellow pods

• F2 Generation Genotype:

  • 1 FFYY
  • 2 FFYy
  • 2 FfYY
  • 4 FfYy
  • 1 FFyy
  • 2 Ffyy
  • 1 ffYY
  • 2 ffYy
  • 1 ffyy

• F2 Generation Phenotype:

  • 9 flat yellow pods
  • 3 flat green pods
  • 3 constricted yellow pods
  • 1 constricted green pod

This gives us a 9:3:3:1 phenotypic ratio in the F2 generation!