Passage of the Agricultural Improvement Act of 2018 (Farm Bill) in December opened a big window of opportunity for many growers to grow Industrial hemp as the new law classifies hemp as a crop. The legislation defines a hemp variety as “industrial hemp” if its tetrahydrocannabinol (THC) concentration in plant dry weight is no more than 0.3%.
Many cannabinoids, the chemical compounds produced by cannabis plants including Δ9-THC, CBD, CBG and others, can be analyzed using high-performance liquid chromatography (HPLC) to separate, identify and quantify each component.
Genetic testing is of great importance for those who are breeding for superior lines and varieties. Application of molecular markers in many vegetable and field crops have significantly accelerated the breeding process. Marker-assisted selection, DNA fingerprinting and database genotyping can also be applied in hemp production and breeding. A DNA marker is available to identify female plants at early stages of growth which has proven to be a tremendously helpful tool for hemp growers and breeders. DNA can be extracted directly from hemp seed or leaf tissue. PCR is performed on the DNA to determine the female/male ratio. The process is extremely fast and can yield results within 72 hours.
Other trait-linked markers (TLM) including a marker linked to drug versus non-drug forms of cannabis are being investigated. DNA fingerprinting and genotyping of strains can be achieved by using a larger number of molecular markers which could help growers and breeders protect their valuable germplasm. Once a genotyping database has been created, the information can be used for hemp molecular breeding to establish hemp lines with stable THC below the 0.3% threshold.
Public research has begun to develop hemp molecular markers that will be available to hemp breeders. This research presents a tremendous cost savings for breeders. However, it might be a while before such data is publicly available and many private breeders need to have molecular tools as fast as possible. In such cases, molecular markers can be developed for interested parties quickly by using their germplasm. The advantage of this approach is increased efficiency of the data as it was developed from a specific germplasm and for application in the same materials. With advancements in sequencing, such projects could be set up quickly and with significant cost efficiency.