The blue trait is most likely caused by a dominant allele (e.g. allele A), while the white trait is caused by a recessive allele (allele a). However, for the diagram to be correct, individuals 1I and 2I must have genotypes Aa (blue) and aa (white) respectively, thus making the punnet squares, the genotypes of their offspring would be Aa (blue) and aa (white). In turn, we can verify that this is correct by observing the third generation since if the blue individuals of the second generation had genotype AA, they could not have white offspring (aa). If we make all the crosses, the genotypes would be as follows:
1 I: Aa 2 I: aa
1 II: Aa 2 II: aa 3 II: aa 4 II: aa 5 II: Aa 6 II: aa 7 II: Aa 8 II: Aa
1 III: Aa 2 III: aa 3 III: aa 4 III: aa 5 III: aa 6 III: Aa or AA 7 III: aa 8 III: Aa or AA 9 III: aa