Powdery Mildew Tolerance

Powdery mildew tolerance refers to genetic traits that confer resistance or reduced susceptibility to powdery mildew infection, a fungal disease caused by Podosphaera and related species. Cannabis cultivars with these traits show slower disease progression, reduced leaf spotting, and lower sporulation rates under high humidity or environmental stress. Lineage records from breeding programs in regions with humid climates frequently report selection for mildew-resistant parent stock. This trait is polygenic, meaning multiple genes contribute to the phenotype, and expression varies significantly based on environmental pressure, plant health, and pathogen strain. Breeders working in this category typically employ field trials and controlled inoculation tests to identify and stabilize resistant germplasm.

Breeders prioritize powdery mildew tolerance in outdoor and greenhouse programs where humidity control is limited or expensive. Introgressing tolerance alleles from resistant parents into commercially desired cultivars requires multi-generational selection and phenotypic evaluation under challenge conditions.