The Vat gene in melon confers resistance to both aphid colonization and aphid transmission of several viruses. QTLs that provide resistance to aphid were localized on the melon genome. We built genetic allelic combinations with/without the resistant allele at the Vat locus and QTLs. These combinations (homozygous for the resistance loci) had a homogeneous genetic background for 90 % of the genome. Plants with different allelic combinations were infested by two Aphis gossypii genotypes NM1 and C9, and observed for acceptance and biotic potential. The Vat gene reduced the acceptance by both aphid genotypes, but only reduced the biotic potential of NM1. QTLs had a complementary effect on acceptance. To predict the durability of the resistance we plan to investigate selection pressures that these combinations exert on aphid populations in field trials.