In a dihybrid cross, F2 phenotypic ratio is 13 : 3. It is case of
A. Complementary genes – Two genes present on separate loci that interact together to produce dominant phenotypic character; neither of them if present alone can express itself are called complementary genes. Due to these genes in the F2 generation, 9:7 ratio of progeny are obtained. It is a modified Mendel dihybrid ratio.
B.Epistatic gene - A gene which masks the action of another gene is termed as epistatic gene and process is called epistasis. Due to these genes in the F2 generation, either 9:3:4 or 12.3.1 ratio of progeny are obtained. It is a modified Mendel dihybrid ratio.
C.Multigenic inheritance - Inheritance of a character due to the presence of more than one genes is called Quantitative inheritance or polygenic inheritance. In this, dominant alleles have cumulative effect. Genes involved in this are called Polygenes. In this type, in the F2 generation 1:4:8:4:1 dihybrid ratio is obtained instead of Mendel dihybrid ratio.
D.Incomplete dominance: Expression of new phenotype in the progeny other than parental phenotypes is called Incomplete dominance.
So, the correct option is ‘Epistatic genes’.