If feather color in parrots is made by 1 autosomal gene with 2 alleles F and f The F is blue and f is yellow F allele shows imcomplete dominance over f allele 2 heterozygous Ff green parrots bred?

Answer 1

First, to restate the question in a more comprehensible form:

Feather colour in parrots is determined by a single autosomal gene. The gene has two alleles, F and f. F causes blue feather colour and f causes yellow feather colour. F shows incomplete dominance over f (i.e, a heterozygote has a mixed phenotype, green feathers). If two green parrots, genotype Ff breed, what colour will the offspring be?

This is a basic Mendelian cross. A similar example, with Punnet square, can be seen in the Wikipedia page for 'Mendelian inheritance', Figure 3. This page is a good starting point for understanding the principles involved.

To directly answer the question, 25% of the offspring will be blue (FF), 25% yellow (ff) and 50% green (Ff).

Answer 2

The 2 heterozygous Ff green parrots will produce offspring with a phenotypic ratio of 1:2:1, where 25% will be blue, 50% will be green, and 25% will be yellow. This is due to incomplete dominance, where the F allele expresses a phenotype that is intermediate between the blue and yellow alleles.