AIIMS2017Botany-Genetics

AIIMS 2017 Botany Mendelian Inheritance MCQ Question

Type: MCQ-conceptual-Medium-Class 12

In pea plants, green pod colour is dominant over yellow pods. 1000 seeds taken from a pea plant on germination produces 760 green pod and 240 yellow pod plants. The parental genotype and phenotype of the seed plant are

A

heterozygous and yellow

B

heterozygous and green

C

homozygous and yellow

D

homozygous and green

Correct Answer

Option C

Detailed Explanation

The parental genotype of the seed plant is homozygous for yellow pods (yy), as indicated by the 240 yellow pod plants produced from the 1000 seeds, which suggests a 3:1 ratio of green to yellow phenotypes. This ratio aligns with a homozygous yellow parent crossed with a heterozygous green pod parent (Yy), resulting in 75% green (Yy and YY) and 25% yellow (yy) offspring. Options A and B are incorrect because they suggest the presence of a dominant green allele, which would not yield the observed ratio, while option D is incorrect as it implies a homozygous green genotype that cannot produce any yellow offspring.

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