Question

A plant with two 'short' genes is crossed with a plant with two 'tall' genes to produce

• A. All short plants
• B. All tall plants
• C. Short and tall plants in the ratio of 1 : 3
• D. Short and tall plants in the ratio of 3 : 1

Answer 1

The correct option is B All tall plants

Both parents are pure breeding, the one that carries same allele for a particular character and passes the trait without change from one generation to next upon selfing. Since “tall” gene is dominant over “short” gene; a cross between two pure breeding tall and short plants will obtain all tall hybrids in F${}_1$ generation. This is because expression of “short” gene is masked by the presence of dominant “tall” gene and it is not expressed in the progeny. The progeny of a cross between two pure breeding dominant and recessive parents obtain uniform dominant progeny. Thus, the correct answer is option B.