Quick Guide: Recommended Practices for Strain Selection and Breeding High Potency Cannabis and High Yield Production of Biomass
Introduction
Breeders and growers must carefully consider various aspects of plant growth when selecting strains to breed and put into production to maximize harvest yield and potency in terms of biomass and cannabinoids. This guide provides data-driven recommendations based on recent research for achieving these goals, focusing on hybrid breeding, early selection criteria, canopy architecture, disease management, and cannabinoid production.
Hybrid Breeding
Data Point: To achieve uniform growth in hybrid cannabis plants, at least one inbred parent is essential. Excessive inbreeding can lead to depression, reducing biomass yield by up to 30%.
Practice: Cross a genetically diverse parent with an inbred parent when creating hybrids. This approach combines the uniformity and stability of the inbred line with the vigor and high yield potential provided by the other parent's genetic diversity.
Early Selection Criteria
Data Point: Basal stem diameter best predicts final dry biomass yield. A robust linear relationship exists between stem diameter and biomass yield (R² = 0.78).
Practice: Measure the basal stem diameter early in the plant’s development. Select plants with larger stem diameters for breeding and cultivation to ensure higher biomass yields.
Canopy Architecture
Data Point: Kite area and circularity are essential to plant architecture and yield predictors. Plants with higher kite circularity (0.76 on average) and optimal branch angles tend to have better light penetration and higher yields.
Practice: Select plants with balanced canopy architectures, an optimal kite area, and branch angles close to 45°. This promotes better light distribution and maximizes photosynthesis efficiency, enhancing biomass production.
Disease Management
Data Point: Powdery mildew (PM) can significantly impact biomass yield and quality. Resistance to PM is multigenic and correlates with later flowering times in outdoor gardens and higher chlorophyll content.
Practice: Select genetic resistance to PM by choosing late-flowering cultivars and those with higher chlorophyll content. Implement regular monitoring and proactive management practices to reduce the impact of PM on your crop.
Cannabinoid Production
Data Point: Total cannabinoid yield is influenced by genetic factors and environmental conditions. High-performing families can exceed 150 g of total cannabinoids per plant.
Practice: Evaluate cannabinoid profiles in your breeding populations to focus on genetic selection for high cannabinoid content. Use environmental controls, such as light, temperature, and nutrient management, to optimize conditions for cannabinoid synthesis.
Biomass Yield Optimization
Data Point: Dry-stripped floral biomass strongly correlates with total wet biomass (R² = 0.96). On average, dry biomass is 30% of wet biomass, and dry-stripped floral biomass is 60% of dry biomass.
Practice: Implement accurate wet biomass measurements at harvest to predict final dry biomass yields. Select plants with higher dry stripped-to-wet biomass ratios to enhance efficiency in biomass production.
Foliar Traits and Growth Rate
Data Point: Leaf morphology, including specific petiole area and leaflet number, correlates with growth rate and biomass yield. Specific petiole area is inversely associated with biomass accumulation (r = -0.51).
Practice: Evaluate leaf traits early in the growing season to identify high-yielding plants. Select plants with optimal leaf and petiole characteristics to ensure vigorous growth and higher biomass yields.
Implementation Strategy
Data Point: Combining the top predictors—stem diameter, kite area, and plant height—explains 67% of the variation in biomass yield.
Practice: Develop a comprehensive selection strategy that includes these key traits. Use a multi-trait selection index to identify the best-performing plants for breeding and cultivation.
Summary
By focusing on these data-driven practices, breeders and growers can optimize the yield and potency of their cannabis crops. Careful selection based on genetic diversity, early growth traits, canopy architecture, disease resistance, and cannabinoid content will produce more robust and productive plants. Implement these recommendations to enhance your breeding programs and cultivation practices, ensuring high-quality and high-yield cannabis production.
