Several millennia of co-evolution and prehistoric human selection have provided the diversity of THC-rich, landrace varietals from which contemporary strains have been developed.
Clandestine cultivation and trade, and the outcrossing nature of this plastic species, have resulted in the diversity of poly hybrid cultivars currently in production.
Currently, the flood of economic interest in this species has resulted in breeding developments that belie the nascent stage of cannabis germplasm development.
Researchers in Oregon have recently identified a single gene which .
Dominant inheritance enables a plant with both copies of the PM resistance gene to be hybridized with a susceptible plant, with all F1 progeny exhibiting resistance to PM disease.
Intellectual and facility investments, and a clear plan with predetermined scoring metrics and objectives, are necessary for success.
Early selection criteria that can be employed include chromosomal analysis to eliminate male plants immediately after germination and assessment of seedling vigor.
Plants with narrow leaf blades, intermediate internode length, and strong stems will enable airflow and inflorescence support to the benefit of labor efficiency.
To assess the relative fitness of individual plants, it is necessary to minimize the environmental differences that should be assumed to exist spatially within all cultivation environments.
Growers who invest the resources necessary to select the best possible cultivars for their climate and market will realize dividends in plant health, quality, and yield.
This example is based on a facility with 1,000 square feet of flowering space available for phenotype trials, with all plants grown from seed.
Observant grow personnel will be familiar with the characteristics of the remaining candidates and can provide valuable anecdotal insight into their fitness for production.
Stewart is currently engaged as a crop consultant and researcher for Xylem Horticulture, providing services to growers in Western Canada, and internationally.