In a Certain Breed of Chicken,an Incompletely Dominant Gene Controls

In a certain breed of chicken,an incompletely dominant gene controls color.The homozygous black (BB),when crossed with the homozygous splashed-white (bb),produces an intermediate gray color pattern referred to as blue.A second gene controls the shape of the comb.The dominant allele (R)produces rose,whereas the recessive allele (r)produces single.A cross between a true-breeding black with a single comb and a true-breeding splashed-white with a rose comb will produce a total of _______ different phenotypes in the F2 generation.