What is the expected percentage of ${\text{F}}_{\text{2}}$ progeny with yellow inflated pod in dihybrid cross involving pea plants with green coloured inflated pod and yellow coloured constricted pod as parental plants ?

In a dihybrid cross involving pea plants, we examine two traits: pod color and pod shape. The parental plants in this case have:

• Green-colored inflated pod (homozygous recessive for color, dominant for shape)
• Yellow-colored constricted pod (homozygous recessive for shape, dominant for color)

These plants represent a classic Mendelian dihybrid cross where the F1 generation will all be heterozygous for both traits, inheriting the dominant traits from both parents. In the F2 generation, we expect a 16-cell Punnett square with four possible phenotypic combinations: two parental types and two recombinant types.

Genotypic and Phenotypic Ratios:

The genes for pod color and pod shape are inherited independently according to Mendel's Law of Independent Assortment. The following are the genotypes and corresponding phenotypes of the F2 generation:

Now, focusing on the question about the yellow inflated pod phenotype, it falls under the recombinant category. The recombination occurs when the alleles for the pod color and pod shape assort in a way that creates a new combination not seen in the parental generation. The expected percentage of F2 progeny with yellow inflated pod is:

18.75% (or 3/16) of the F2 generation is expected to have the yellow inflated pod phenotype.

Conclusion:

Therefore, when crossing a pea plant with green inflated pods and a yellow constricted pod with each other in a dihybrid cross, the expected percentage of F2 progeny with yellow inflated pods is 18.75%. This represents a recombinant phenotype resulting from genetic recombination in the F2 generation.