Answer:
Genotypic ratio = 16 WwDd: 0
Phenotypic ratio = 16 white, disk shaped fruit : 0 yellow, sphere shaped fruit
Explanation:
This question involves two different genes coding for fruit color and fruit shape respectively. The allele for white fruit color (W) is dominant over yellow fruit color (w) and disk shaped fruit (D) is dominant over sphere-shaped fruit (d).
According to this question, If a squash plant pure-breeding for white, disk shaped fruit (WWDD) is crossed with a plant pure breeding for yellow, sphere shaped fruit (wwdd), the following gametes will be produced by each GAMETE:
WWDD - WD, WD, WD, WD
wwdd - wd, wd, wd, wd
Using these gametes in a punnet square, all of the offsprings will have genotype WwDd, which is phenotypically white and disk shaped fruit.
The genotypic ratio is 4 WwDd: 0
The phenotypic ratio is 16 white, disk shaped fruit : 0 yellow, sphere shaped fruit.