Answer: The allele for the tail spike is 'N' and for the non rail spike is 'n'. This indicates that tail spike is a dominant trait that is it can express even in the heterozygous genotype ( Nn). On the pther hand, no tail spike is recessive that is it will only express when it is present in a homozygous state (nn).
According to the question, the genotypes of the parents are-
Female dragon- NN and Male dragon- nn
When these parents mate, they will produce all offsprings with tail spikes. The genotype of potential offsprings is Nn.