Ratio of plants produced in the monohybrid cross in the F1 and F2 generation

In a monohybrid cross, two individuals with contrasting traits for a single characteristic are crossed. This type of cross allows us to observe the inheritance pattern of a single gene and understand how traits are passed on from one generation to the next.

F1 Generation:
The F1 generation is the first filial generation, which is the result of crossing two true-breeding parents (homozygous individuals) with different traits. In a monohybrid cross, one parent is homozygous dominant (AA) and the other parent is homozygous recessive (aa).

- The F1 generation will consist of all heterozygous individuals (Aa) for the trait under consideration.
- The ratio of plants produced in the F1 generation will be 100% heterozygous (Aa).

F2 Generation:
The F2 generation is the second filial generation, which is obtained by crossing two F1 individuals. In this generation, we can observe the segregation of alleles and the different combinations they can form.

- The F2 generation can produce plants with three different genotypes: homozygous dominant (AA), heterozygous (Aa), and homozygous recessive (aa).
- The ratio of plants produced in the F2 generation follows a classic Mendelian ratio, known as the 1:2:1 ratio.
- This means that approximately 25% of the plants will be homozygous dominant (AA), 50% will be heterozygous (Aa), and 25% will be homozygous recessive (aa).

Explanation:
- The ratio of plants in the F1 generation is all heterozygous (Aa) because the dominant allele (A) masks the expression of the recessive allele (a).
- In the F2 generation, the heterozygous individuals (Aa) can produce both dominant and recessive alleles when they undergo independent assortment during gamete formation.
- When these gametes combine during fertilization, they can produce offspring with different genotypes, resulting in the observed 1:2:1 ratio of homozygous dominant, heterozygous, and homozygous recessive plants.

Summary:
In a monohybrid cross, the ratio of plants produced in the F1 generation is 100% heterozygous (Aa), while in the F2 generation, the ratio follows a 1:2:1 ratio, with approximately 25% homozygous dominant (AA), 50% heterozygous (Aa), and 25% homozygous recessive (aa) plants. This ratio demonstrates the principles of Mendelian inheritance and the segregation of alleles during gamete formation.

F1 all are tall F2 3:1 .... 3 are tall .... 1 dwarf