Flower Diameter in Sunflowers Is a Quantitative Trait

Multiple Choice

Flower diameter in sunflowers is a quantitative trait. A plant with 6-cm flowers, from a highly inbred strain, is crossed to a plant with 30-cm flowers, also from a highly inbred strain. The F₁ have 18-cm flowers. F₁ × F₁ crosses yield F₂ plants with flowers ranging from 6 to 30 cm in diameter, in approximately 4-cm intervals (6, 10, 14, 18, 22, 26, 30) . The number of different genes influencing flower diameter in this plant is:

A) three.
B) four.
C) five.
D) six.
E) seven.