CrossHybridisierung

CrossHybridisierung, or cross-hybridization, is the deliberate or natural crossing of individuals from different genetic lineages to produce hybrids. It can occur within a species (intraspecific) or between different species or varieties (interspecific), with the goal of combining desirable traits such as yield, quality, disease resistance, or stress tolerance.

In plants, cross-hybridization is a central tool in breeding and has driven major advances in crops. Hybrids may exhibit heterosis (hybrid vigor), and breeders often pursue introgression, the gradual introduction of specific alleles from one line into another through repeated backcrossing. In animals, cross-hybridization is less common and more constrained by reproductive barriers, genetic incompatibilities, and regulatory considerations.

The process typically involves selecting parent lines, conducting controlled crosses, growing and evaluating offspring, and selecting individuals with desired trait combinations. When barriers to fertility or maturity arise, techniques such as embryo rescue or chromosome doubling (polyploidization) can be employed, particularly in plants, to achieve viable and fertile hybrids. Polyploid crops like bread wheat and cotton illustrate how chromosome doubling can stabilize hybrid genomes and enable successful breeding.

Challenges to cross-hybridization include prezygotic barriers (such as differences in flowering time or mating compatibility) and postzygotic barriers (hybrid inviability or sterility). Despite these obstacles, cross-hybridization remains a foundational approach in genetics, plant and animal breeding, and studies of evolution, enabling gene introgression, trait mapping, and the exploration of speciation processes.