The dominance hypothesis of heterosis was first proposed by

The dominance hypothesis of heterosis was first proposed by Davenport (1908).
The dominance hypothesis attributes heterosis to canceling of deleterious or inferior recessive alleles contributed by one parent, by beneficial or superior dominant alleles contributed by the other parent in the heterozygous genotypes at different loci.
It was proposed by Charles Davenport in 1908 and is the most widely accepted hypothesis among the explanation of heterosis.