Question

Rahul observed a plant in his garden. He hypothesized that the stem height exhibited incomplete dominance. To check for his, he created true-breeding lines of tall and short plants. He then crossed these and sampled 1000 progeny. Which of the following cases, matches his hypothesis?

(a) 500 tall plants, 250 intermediate plants, and 250 small plants

(b) 250 tall plants, 500 intermediate plants, and 250 small plants

(c) 250 tall plants, 250 intermediate plants, and 500 small plants

(d) 125 tall plants, 750 intermediate plants, and 125 small plants

The question was asked in an internship interview.

My enquiry is from Inheritance Principles topic in portion Principles of Inheritance and Variation of Biology – Class 12

Answer 1

Correct option is (b) 250 tall plants, 500 intermediate plants, and 250 small plants

To explain I would say: The phenotypic ratio of the progeny that exhibits incomplete dominance is 1:2:1. Therefore, of 1000 plants sampled from the progeny, 250 should be tall, 250 should be small, and 500 intermediate plants if incomplete dominance holds.