NEETZoologyPrinciples of Inheritance and Variation
A pea plant heterozygous for both seed shape (round) and seed colour (yellow) is crossed with a plant producing wrinkled, green seeds. If a total of 400 progenies are obtained from this cross, what is the expected number of plants producing round and green seeds?
Options
- A75
- B100
- C200
- D225
Correct answer
B. 100
Step-by-step solution
The cross described is a dihybrid test cross. Genotype of the heterozygous round and yellow seed plant: RrYy Genotype of the wrinkled and green seed plant (double recessive): rryy Cross: RrYy rryy The gametes produced by RrYy are RY , Ry , rY , and ry in equal proportions. The gametes produced by rryy are all ry . The expected phenotypic ratio of the progenies is 1:1:1:1 (Round Yellow : Round Green : Wrinkled Yellow : Wrinkled Green). The fraction of progenies with round and green seeds ( Rryy ) is 1 4 . Expected n