Question

In Snapdragon, when pink flowers are crossed with white flowers the ratio of pink flowers and white flowers in progeny is
A. 10% Red
B. Red and White in 3:1 ratio
C. Pink and White in 1:1 ratio
D. Pink Red and White in 1:2:1 ratio

Answer 1

Hint: Antirrhinum is a plant genus commonly known as dragon flowers or snapdragons because of a flower resemblance to the dragon's face that opens and closes its mouth when it is laterally squeezed. They are native to the rugged regions of Europe , the United States and North Africa.

Complete Answer:

	r	w
r	rr	rw
w	rw	ww

r=Pink Flower
w=white flower
rw=pink flower

Genotype:
rr=25%
rw=50%
ww=25%

Phenotype:
Red=25%
Pink=50%
White=25%

	R	r
r	Rr(pink)	rr(white)
r	Rr(pink)	rr(white)

Snapdragon displays incomplete dominance, where both genes express themselves in the same heterozygous state.
Pink flower genotype = Rr
White flower genotype = rr
In the cross Rr above: rr = 2: 2 = 1: 1
- The pink and white flowers are also in similar proportions.
- The right choice is 'Pink and white in 1:1 ratio.'

Thus the correct answer is option C Pink and white in 1:1 ratio.

Note: Several species of Antirrhinum are self-incompatible, which means that a plant can not be fertilized by its own pollen. Self-incompatibility in the gene has been studied since the early 1900s.
- Self-incompatibility in Antirrhinum species is regulated gametophytically and has many important features in the Rosaceae and Solanaceae self-incompatibility systems.
- In addition to growing plants for cut flowers, seeds have been used to extract edible oils, especially in Russia, while leaves and flowers have been considered to possess antiphlogistic (anti-inflammatory) properties and have been used in poultices. A green colour was also extracted from the flowers.