Question

The trait for tall pea plants is (T) and the trait for short pea plants is (t). The trait for smooth pea plants is (R) and the trait for wrinkled is (r).Two plants are crossed producing a F1 generation of plants with 612 tall and smooth pea plants and 188 short and wrinkled pea plants.What would be the most likely genotype of the parental generation?

Answer 1

The parental generation most likely had heterozygous genotypes (TtRr) for both the tall-smooth and short-wrinkled traits. This is indicated by the F1 generation having a 9:3:3:1 phenotypic ratio which corresponds to the traits observed (tall-smooth and short-wrinkled).

Step-by-step explanation:

Understanding Pea Plant Genetics

Considering that the student observed 612 tall and smooth pea plants and 188 short and wrinkled pea plants in the F1 generation, we can infer that both tall (T) and smooth (R) traits are dominant. Since the short and wrinkled trait numbers (188) are roughly a quarter of the total, we can deduce that the parental generation most likely had heterozygous genotypes for both traits (TtRr).

Therefore, each parent contributed a recessive allele (t and r) to produce the short, wrinkled phenotype, following Mendelian principles of inheritance. The dominant traits' genotypic ratio typically occurs in a 9:3:3:1 pattern in dihybrid crosses.

In this case, the observation of such distinct dominant and recessive phenotypes aligns with the expected Mendelian dihybrid ratio, indicating that each parent was heterozygous for both traits (TtRr x TtRr).

Answer 2

P generation = TtRr × TtRr i.e both parents were heterozygote for both traits

Step-by-step explanation:

This question involves two genes encoding the height and texture in pea plants respectively. The alleles for tall and smooth pea traits are dominant over the alelles for short and wrinkled traits.

According to this question, two plants are crossed to produce F1 offsprings as follows: 612 tall and smooth pea plants and 188 short and wrinkled pea plants.

First, we turn this derived number of offsprings into ratio by dividing by the smallest number (188)

612/188 : 188/188

3.25 : 1

Approximately; we can say this is 3 (tall and smooth) : 1 (short and wrinkled)

Based on this ratio, which was got by Mendel for his F1 offsprings when he crossed pea plants, the parental generation has a heterozygous genotype (TtRr).