Answer:
Genotypic ratio F2 = 1:2:1
Phenotypic ratio F2 = 3:1
Step-by-step explanation:
In this case, parental genotypes can produce only one type of gamete, i.e., one parent can produce only D gametes, while the other parent can produce only d gametes. Therefore, all F1 generation will be heterozygous (Aa). An F1 hybrid is the first filial generation of offspring obtained from crossing between different parent types. The F1 will produce two gametes (A; a) in a ratio 1:1, thereby the F2 obtained by crossing F1 offspring will have a phenotypic ratio of 3:1 (3 D_; 1 dd) and a genotypic ratio of 1:2:1 (1 AA; 2 Aa; 1 aa).