Question

A tall pea plant with round seeds (TTRR) is crossed with a dwarf wrinkle seeded plant (ttrr). F${}_1$ generation has tall plants with round seeds. What is the proportion of dwarf plants with wrinkled seeds in F${}_2$ generation?

• A. Zero
• B. 1/2
• C. 1/4
• D. 1/16

Answer 1

The correct option is D 1/16

As we know that tallness (T) is dominant over dwarfism (t) and round seed (R) is dominant over wrinkled (r).

Parent Generation, P${}_1$ : TTRR x ttrr

F${}_1$ generation : TtRr (tall plant, round seed)

P${}_2$ generation : TtRr x TtRr

Gametes TtRr ---> TtRr	TR	Tr	tR	tr
TR	TTRR (tall plant, round seed)	TTRr (tall plant, round seed)	TtR R (tall plant, round seed)	TtRr (tall plant, round seed)
Tr	TTRr (tall plant, round seed)	TTrr (tall plant, wrinkled seed)	TtRr (tall plant, round seed)	Ttrr (tall plant, wrinkled seed)
tR	TtRR (tall plant, round seed)	TtRr (tall plant, round seed)	ttRR (dwarf plant, round seed)	ttRr (dwarf plant, round seed)
tr	TtRr (tall plant, round seed)	Ttrr (tall plant, wrinkled seed)	ttRr (dwarf plant, round seed)	ttrr (dwarf plant, wrinkled seed)

Thus, dwarf plant, wrinkled seeded progeny (ttrr) in F${}_2$ generation= 1/16; D is correct answer.