Expected Phenotypic Ratios in Offspring from a Cross between a Plant with Yellow Seeds (TtYy) and a Tall Plant with Green Seeds (Ttyy)

When a cross is made between a plant with yellow seeds (TtYy) and a tall plant with green seeds (Ttyy), the offspring will inherit a combination of traits from both parental plants. In this case, the traits being considered are seed color (yellow or green) and plant height (tall or dwarf).

To evaluate the expected proportions of phenotypes in the offspring, we need to consider the principles of Mendelian genetics and the rules of inheritance. Mendel's laws of segregation and independent assortment are particularly relevant in this context.

1. Law of Segregation:
According to this law, each individual has two alleles for each gene, and these alleles segregate (separate) during gamete formation, with each gamete receiving only one allele for a particular trait.

2. Law of Independent Assortment:
This law states that the inheritance of one trait is independent of the inheritance of another trait, as long as the traits are located on different chromosomes or are far apart on the same chromosome.

Now let's break down the expected proportions of phenotypes in the offspring into two categories:

(a) Tall and Green:
To be tall, the offspring must inherit at least one dominant allele for plant height from the tall parental plant (T). Similarly, to have green seeds, the offspring must inherit at least one recessive allele for seed color from the green parental plant (y). Therefore, the genotype of the offspring for the tall and green phenotype can be TtYy or Ttyy.

The phenotypic ratio for tall and green offspring can be determined by considering the possible genotypes resulting from the cross:

- TtYy: 1/4 of the offspring will have this genotype, resulting in tall plants with yellow seeds.
- Ttyy: 1/4 of the offspring will have this genotype, resulting in tall plants with green seeds.

Thus, the expected phenotypic ratio for tall and green offspring is 1/4 + 1/4 = 2/4, which simplifies to 1:1 or 50%.

(b) Dwarf and Green:
To be dwarf, the offspring must inherit two recessive alleles for plant height from both parental plants (tt). Additionally, to have green seeds, the offspring must inherit at least one recessive allele for seed color from the green parental plant (y). Therefore, the genotype of the offspring for the dwarf and green phenotype can be ttyy.

The phenotypic ratio for dwarf and green offspring can be determined by considering the possible genotype resulting from the cross:

- ttyy: 1/4 of the offspring will have this genotype, resulting in dwarf plants with green seeds.

Therefore, the expected phenotypic ratio for dwarf and green offspring is 1/4 or 25%.

In summary, when a cross is made between a plant with yellow seeds (TtYy) and a tall plant with green seeds (Ttyy), the expected proportions of phenotypes in the offspring can be as follows:
- Tall and green: 50%
- Dwarf and green: 25%

Note: The remaining 25% of the offspring will have other combinations of traits, such as tall plants with yellow seeds and dwarf plants