Page 23 - Griffin Gazette Issue 2 - 2020

HEMP INVASIVENESS

Field production of hemp is finally ramping up in many states. This type of
production presents its own set of problems, as hemp exhibits the potential to
become invasive and establish wild populations. Wild cannabis presents problems
due to the ability of cannabis pollen to travel up to 3 miles, as observed in some
studies in Kansas. While hemp grown for fiber remains unaffected by rogue
pollen, hemp grown for CBD must remain unpollinated to achieve optimal yields. GEOGRAPHICAL LOCATION
It is possible that anywhere suitable for field hemp production will also support a
generation of rogue seedlings post-harvest. The University of Florida is looking at
the environmental tolerance of seedlings under varying conditions to assess how Many universities and states are conducting
viable rogue seedlings would be; other locations must conduct the same trials for state-based variety trials. Over the course of
their environments to assess their individual risks. these trials, researchers characterize such
traits as: total light and day length response,
temperature tolerances, seasonality, and
strength of genetic vs environmental responses.
Dr. Allison Justice, hemp researcher and owner
of The Hemp Mine, has experienced first-hand
the importance of selecting an appropriate
variety for the growing region. “Some varieties
in one region will also grow well in other
regions, and then some do not. Last growing
season, we received clones from Colorado and
we planted in our fields in South Carolina. A
couple of the varieties flowered prematurely but
the greater issue was the disease pressure. In
our trial this past season we observed this very
clearly as the varieties from Colorado showed
much higher disease pressure and occurrence.”
Active research is being conducted at Kansas
State, University of Florida, North Carolina
State, and South Carolina State.

PRODUCTION SPECIFICS

Hemp has had little research into the finer biological processes
occurring throughout the growth cycle. Recently, several labs have
conducted investigations focusing on processes important to
commercial cultivation. One lab focused their efforts on studying
water and nitrogen use efficiencies over an entire canopy and
found that long term water stress leads to leaf senescence and
lower yields, while limiting nitrogen had less of an impact. Another
lab dove into the effects of varying temperature combined with
nitrogen levels on photosynthesis. Optimal temperatures for
cannabis lay between 25-35 C, after which activity began to
decline. Effects of low nitrogen nutrition only became apparent
as light levels began to increase past 500 umol/m2/s, with lower
nitrogen treatments seeing a leveling off in photosynthesis activity
past this point.

GRIFFIN GAZETTE 2020 | 23