Question

The monohybrid genotypic ratio 1:2:1 in ${F_2}$ generation indicates
A. Segregation
B. Independent assortment
C. Dominance
D. Incomplete dominance

Answer 1

Genotype ratio indicates the number of times a characteristic of an organism will be seen in the offspring after the cross happens.
Monohybrid cross refers to the inheritance of a single type of trait by two parents at a time but in dihybrid cross two types of trait were studied together like- height and shape of seeds.
According to Mendel each factor in a pair separate during gamete formation so that each gamete receives only factor from the pair.

Complete answer:
When Mendel self crossed the ${F_1}$ hybrids then the ${F_2}$ generations were raised.
In the ${F_2}$ generation Mendel found that 3 plants are taller and one plant was short (dwarf).
Due to the segregation process ${F_2}$ generation indicates genotype ratio 1:2:1 in a monohybrid crossing and here phenotype can be either 3:1 ratio or 1:2:1 ratio depending on types of the genes.
Segregation says that the height (TT, Tt or tt)) genes will be separate during the process of gamete formation and they will go to different offspring.
Independent assortment was observed in dihybrid cross and it says that separate genes for separate traits are passed independently of one another to offspring from parents.
The genotype found in the independent assortment will be 1:2:1:2:4:2:1:2:1.

So, here option (A) Segregation will be the correct answer.

Note: Mendel performed his experiments in a pea plant that is Pisum sativum. He selected seven traits among a number of characters of that plant.
According to the dominance and incomplete dominance genotypes will remain same but the difference can be spotted by their phenotype only.