Question

In Mendel’s experiments, tall pea plants (T) are dominant over dwarf pea plants (t).

1. What is the phenotype and genotype of the F₁ generation if a homozygous tall plant is crossed with a homozygous dwarf plant?
2. Draw a Punnett square board to show the gametes and offspring when both the parents are heterozygous for tallness.
3. What is the phenotypic ratio and genotypic ratio of the above cross in (b)?
4. State Mendel’s Law of Dominance.
5. What is a Dihybrid Cross?

Answer 1

1. Phenotype: Tall plants
   Genotype: Heterozygous tall plants
2. 
   

   Gamets	T	t
   T	TT	Tt
   t	Tt	tt

3. Phenotypic ratio: 3 : 1
   Genotypic ratio: 1 : 2 : 1
4. Mendel’s law of dominance states that in a given cross between two organisms with pure contrasting alleles or characters, only one allele is expressed in F₁ generation. The character that appears is called dominant and the other recessive.
5. The cross in which two features of an organism/plant are taken together at a time.