Question

A pea plant having violet coloured flowers with unknown genotype was crossed with a plant having white coloured flowers, in the progeny 50% of the flowers were violet and 50% were white. The genotypic constitution of the parent having violet coloured flowers is

• A. Homozygous
• B. Merozygous
• C. Heterozygous
• D. Hemizygous

Answer 1

Answer: (C)

Heterozygous

Test cross is the cross which is done to find out the genotype of parents. Suppose the genotype of a pea plant parent with violet flowers is CC and that of homozygous recessive parent is cc. If the F${}_1$ hybrid had yielded 50% violet flowers and 50% white flowers it is a clear case of heterozygous parents which means that the genotypes of parents are Cc and cc.

Genotype Cc (Violet flowers) X cc (white flowers)

Gametes C and c c and c

Punnette square

Gametes	C	c
c	Cc	cc
c	Cc	cc

Thus, 50% offsprings are with violet flowers and 50% with white flowers.