Key Insights for Cannabis Breeders: Enhancing Biomass and Cannabinoid Yield in Hemp Hybrids
Hemp (Cannabis sativa) is a versatile plant prized for its fiber, seeds, and cannabinoids like CBD and THC. Improving yield and quality through breeding hemp hybrids can transform the industry. This blog delves into a recent study by Cornell University researchers that uncovers critical morphometric relationships contributing to biomass and cannabinoid yields in hemp hybrids.
Study Overview
Cornell University researchers investigated how hemp plants' various physical traits (morphometrics) relate to their biomass (total plant material) and cannabinoid yields. The study involved 23 hemp families with diverse genetic backgrounds to identify the best predictors of these traits.
Key Findings
Biomass Prediction
Wet and Dry Biomass Correlation: There is a strong linear relationship between the wet and dry biomass of hemp plants. This means that measuring the wet biomass can accurately estimate the dry biomass, which is crucial for evaluating yield.
Basal Stem Diameter: The thickness of the stem at its base is the single best predictor of the final dry floral biomass yield. Thicker stems tend to produce more biomass.
Canopy Architecture
Impact on Biomass Yield: The shape and structure of the plant canopy significantly impact biomass yield. Canopy architecture can be categorized into different types, each influencing the plant's growth and yield potential.
Classification Method: Measuring the height, maximum canopy diameter, and height at the maximum diameter helped develop a new method to classify canopy architecture, guiding breeding selections.
Genetic Variation and Breeding
Within-Family Variation: Significant variation for both morphological and cannabinoid traits was observed, reflecting the genetic diversity of the parent plants.
Inbreeding Depression: Self-pollinated (inbred) plants showed signs of reduced vitality and yield. Therefore, at least one parent in hybrid breeding should be inbred to achieve uniform growth and yield.
Floral Phenology (Flowering Time)
Importance of Flowering Time: Early flowering plants often produce less biomass because they stop growing sooner. Understanding the genetic basis for flowering time is essential for breeding uniform and high-yielding cultivars.
Disease Resistance
Powdery Mildew: This common hemp disease affects biomass yield and quality. Breeding for disease resistance is crucial to ensure high yields and good quality.
Cannabinoid Profiles
Variation in Cannabinoid Content: There is wide variation in cannabinoid content within and among families. Selecting for specific cannabinoid profiles requires understanding the genetic factors influencing these traits.
Practical Implications for Breeders and Farmers
For Breeders
Focus on Basal Stem Diameter: Select plants with thicker stems as a key criterion for higher biomass yield.
Use Canopy Architecture Measurements: Identify high-yielding plants early in the growing season by measuring canopy architecture.
Breed for Disease Resistance: Minimize yield loss and improve quality by selecting for resistance to powdery mildew.
Select for Flowering Time: Ensure flowering time matches the growing season to optimize biomass production.
For Farmers
Measure Wet Biomass: Use wet biomass measurements to estimate dry biomass and plan for harvesting.
Choose High-Yielding Cultivars: Select cultivars with desirable canopy architecture and thick basal stems for better yields.
Implement Disease Management: Protect plants from powdery mildew with effective disease management practices.
Conclusion
By identifying these key traits and relationships, this research provides valuable insights for breeding and growing high-yielding, high-quality hemp cultivars. Emphasizing traits like basal stem diameter, canopy architecture, and disease resistance, alongside understanding genetic variation and flowering times, can significantly enhance hemp breeding programs.
This research was conducted by experts from the Horticulture Section, Plant Pathology and Plant-Microbe Biology Section, and Plant Biology Section at Cornell University, with contributions from Çankırı Karatekin University in Turkey. The findings are published under an open-access license, allowing unrestricted use and distribution.
