A plant of genotype AABbCC is selfed. Phenotypic ratio of F₂ generation would be:-

Key Points

• According to Mendelian genetics, the expression of a character is determined by a pair of alleles.
• The alleles can either be dominant or recessive.
• These alleles can occur in 2 ways:
  • Homozygous - It is the condition in which the pair of alleles determining a phenotype is identical, either both dominant or both recessive.
  • Heterozygous - It is the condition where 2 different types of alleles are present, one dominant and one recessive. Here, the character expressed is dominant.
• Genotype - It is the allelic constitution of a gene determining a particular character.
• Phenotype - It is the expressed character.
• Selfing - It is the process of self-fertilization of a plant, meaning both male and female gametes are used from the same plant.

Important Points

• In the given question, the plant with genotype AABbCC has 3 pairs of alleles -
  • AA - It is homozygous dominant
  • Bb - It is heterozygous
  • CC - It is homozygous dominant
• Thus, the gametes produced by this plant can be of 2 types only - ABC and AbC.
• We can find the phenotypic and genotypic ratios of F₂ generation from the following diagram.

Explanation:

• The genotypes AABBCC and AABbCC will give the same phenotype because the pair BB and Bb both will express the dominant character.
• The genotype AAbbCC will have a different phenotype because the pair 'bb' will express the recessive character.
• Thus the phenotypic ratio of F₂ generation will be 3 : 1.