Question

In snapdragons red flower colour (FR) is incompletely dominant to white flower colour (FW). The heterozygote has pink flowers. Normal broad leaves (PB) are incompletely dominant to narrow, grass-like leaves, (PN). The heterozygote has intermediate leaf width.

(a) If a red-flowered, narrow leaved snapdragon is crossed with a white-flowered broad leaved one, what will be the phenotypes in the F1 generation?
(b)
Now draw a branch diagram to show what will be the proportions of the different phenotypic classes in the F2 generation from an F1 x F1 cross.

Answer 1

In snapdragons, red flower color is incompletely dominant to white flower color, while broad leaves are incompletely dominant to narrow leaves. The F1 generation will have pink flowers and intermediate leaf width. The F2 generation will have red, pink, and white flowers in a ratio of 1:2:1.

In snapdragons, red flower color (FR) is incompletely dominant to white flower color (FW). The heterozygote has pink flowers. Normal broad leaves (PB) are incompletely dominant to narrow, grass-like leaves (PN). The heterozygote has intermediate leaf width.

(a) When a red-flowered, narrow-leaved snapdragon is crossed with a white-flowered, broad-leaved one, the phenotypes in the F1 generation will be pink flowers and intermediate leaf width.

(b) In the F2 generation from an F1 x F1 cross, the phenotypic classes will be red flowers, pink flowers, and white flowers in a ratio of 1:2:1 for each phenotype.