. The phenotypic ratio in dihybrid cross is


A: 9 : 3 : 3 : 1

B: 9 : 2 : 2 : 1

C: 7 : 2 : 2 : 3

D: 5 : 3 : 3 : 2

Best Answer

Explanation:

  • Dihybrid is a cross between two individuals differing in two traits/characters.
  • In Mendel's dihybrid cross, the parents are - plants with round yellow colored seeds (RRYY) and plants with green colored wrinkled seeds (rryy). 
  • The F1 progeny are round and yellow seeds (RrYy).
  • The F1 progeny is allowed to self-fertilize to produce F2 generation exhibiting 4 different phenotypes-Yellow round (9), yellow wrinkled (3), green round (3), and green wrinkled seed plants (1). 
  • The phenotypic ratio of the dihybrid cross is ratio 9:3:3:1( round yellow seeds: wrinkled yellow seeds: round green seeds: wrinkled green seeds).
  • The dihybrid cross is shown in the figure.

phenotypic ratio in dihybrid cross

Final Answer: Hence, the correct answer is (A)  9 : 3 : 3 : 1.

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