(i) Give the genotype and phenotype of the plants of F1 generation.

Question

A homozygous tall plant (T) bearing red coloured (R) flowers is crossed with a homozygous dwarf (t) plant bearing white (r) flowers:

(i) Give the genotype and phenotype of the plants of F₁ generation. 

(ii) Mention the possible combinations of the gametes that can be obtained from the F₁ hybrid plant.

(iii) State the Mendel's law of Independent Assortment. 

(iv) Mention the phenotypes of the off springs obtained in F₂ generation. 

(v) What is the phenotypic ratio obtained in F₂ generation ?

Answer 1

(i) Genotype of F₁ generation: TtRr 

Phenotype of F₁ generation: Tall plants bearing red flowers 

(ii) The selfing of F₁ generation - TtRr will yield following gametes -TR, Tr, tR and tr 

The possible combinations of these gametes are given in the following Punnett square :

(iii) Mendel's law of independent assortment: 

This law was deduced from a dihybrid cross, where simultaneous inheritance of two different characters was considered. According to this law, the alleles of two different characters assort or separate independently of one another at the time of gamete formation. The alleles are thus free to recombine and form new combinations in the subsequent generations.

(iv) The F₂ generation phenotypes would be - . 

• Tall plants with red flowers . 
• Tall plants with white flowers . 
• Dwarf plants with red flowers . 
• Dwarf plant with white flowers

Out of these, tall plants with white flowers and dwarf plants with red flowers were the recombinants.

(v) The phenotypic ratio of F₂ generation would be 9:3:3:1.