Question

A cross between a blue blahblah bird & a yellow blahblah bird produces offspring that are green.  The color of blahblah birds is determined by just two alleles. 
a) What are the genotypes of the parent blahblah birds in the original cross? 
b) What is/are the genotype(s) of the green offspring? 
c) What would be the phenotypic ratios of offspring produced by two green blahblah birds?

Answer 1

A) assuming B = blue and Y = yellow and BY = green (this would work only with incomplete dominance) then the genotype of the parents would have to be BB x YY
B) All BY
C) BY x BY = BB, BY, BY, YY...so, 1BB:2BY:1YY