3 : 1
Heterozygous trait is when for a particular gene or genes there are two different alleles.
Dihybrid cross between individuals that are heterozygous for each trait
Cross A x B
Genotype Hh x Hh
H h
H HH Hh
h Hh hh
Four possible phenotype : HH Hh Hh hh
Since 'H' is dominant allele and 'h' is recessive allele so dominant allele will express itself in both heterozygous and homozygous form.
3 : 1