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NEETZoologyPrinciples of Inheritance and Variation

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): When a pea plant with violet flowers and tall stem is test-crossed, and it produces all tall plants with violet and white flowers in a 1:1 ratio, the parent genotype must be WwTT. Reason (R): The parent plant in this cross is homozygous dominant for stem height and heterozygous for flower colour. I

Options

  1. ABoth Assertion and Reason are true but Reason is not the correct explanation of Assertion.
  2. BBoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
  3. CAssertion is true but Reason is false.
  4. DAssertion is false but Reason is true.

Correct answer

B. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

Step-by-step solution

A test cross involves crossing the dominant phenotype with the homozygous recessive parent (wwtt). Since all the progeny plants are tall, the parent must be homozygous dominant for stem height (TT). Since the progeny shows a 1:1 ratio for violet and white flowers, the parent must be heterozygous for flower colour (Ww). Therefore, the genotype of the parent plant is WwTT. The Assertion (A) is true. The Reason (R) correctly states that the parent is homozygous dominant for height and heterozygous for flower colour, w

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