Disease Resistance Polygenes

Disease resistance polygenes are multiple genetic loci that collectively confer resistance to fungal, bacterial, and viral pathogens in cannabis plants. Rather than single-gene immunity, polygenic resistance involves many small-effect alleles working together, making it more durable and less prone to pathogen adaptation. Breeders have identified polygenic resistance to powdery mildew, gray mold, and root pathogens across various landrace and hybrid germplasm. This trait is inherited additively and expressed variably depending on environmental stress, plant age, and population heterozygosity. Understanding polygenic resistance frameworks helps breeders select stable, multi-pathogen-resistant cultivars for cultivation in diverse climates.

Breeders working with disease resistance typically employ marker-assisted selection (MAS) and multi-generation crossing to pyramid favorable alleles from diverse parents. Polygenic approaches are preferred over single R-genes because they provide broader, more durable protection and reduce crop loss to evolving pathogen races.