hybrid

An individual produced from genetically different parents. The term is often reserved by plant breeders for cases where the parents differ in several important respects. On the other hand, it may be used by geneticists for the F₁ of a monohybrid cross, where the only difference is in a pair of alleles at a single gene. Interspecific hybrids, resulting from a cross between different species, are often sterile (*hybrid sterility) if derived from haploid gametes, but this may be overcome by polyploidy (see allopolyploidy). Hybrids produced from different varieties of the same species (*F1 hybrids) are often more vigorous than either parent, so although they cannot breed true, they may be favoured by agriculturalists. See also heterosis , graft hybrid.