Question

A tall pea plant with round seeds (TTRR) is crossed with a short pea plant with wrinkled seeds (ttrr). The F₁ generation will be ______.

Options

• 25% tall with round seeds

• 50% tall with wrinkled seeds

• 75% tall with wrinkled seeds

• 100% tall with round seeds

Answer 1

A tall pea plant with round seeds (TTRR) is crossed with a short pea plant with wrinkled seeds (ttrr). The F₁ generation will be 100% tall with round seeds.

Explanation:

• The parental generation consists of:

  • Tall, round-seeded plant (TTRR)
  • Short, wrinkled-seeded plant (ttrr)

• The F₁ generation is formed by crossing these two plants:

  • TTRR × ttrr

• Since T (tall) is dominant over t (short) and R (round) is dominant over r (wrinkled), all offspring will inherit:

  • One T from the tall parent and one t from the short parent → Tt (tall)
  • One R from the round parent and one r from the wrinkled parent → Rr (round seeds)

• Therefore, all F₁ offspring will be heterozygous (TtRr), meaning 100% of them will be tall with round seeds.