Hemp goes `hot' due to genetics, not environmental stress

Date:
July 28, 2021
Source:
Cornell University
Summary:
A new study debunks misinformation on websites and in news articles
that claim that environmental or biological stresses -- such as
flooding or disease -- cause an increase in THC production in
hemp plants.



FULL STORY ========================================================================== Contrary to claims that environmental or biological stresses cause an
increase in THC production in hemp, a new Cornell University study finds
no evidence that stress on hemp plants increases THC concentrations or
ratios of CBD to THC.


========================================================================== Growing hemp for CBD (cannabidiol) is a burgeoning industry, but when
hemp contains more than the legal limit of THC, the plants can test
"hot." State and federal regulations classify hemp as containing 0.3%
or less THC; when plants exceed that amount, farmers can lose their
entire crop.

"One of our goals in our research and in fulfilling our extension mission
is to reduce the risks to growers as much as possible," said Larry Smart, senior author of the study and professor in the horticulture section of
the School of Integrative Plant Science in the College of Agriculture
and Life Sciences.

"With this research, growers should feel some comfort that stresses do
not seem to have a strong effect on changing the ratio of CBD to THC."
In the study, lead author Jacob Toth, a graduate student in Smart's lab, created a series of plots in Geneva, New York, that included control plots
and five stress treatments applied to three genetically unrelated high-CBD
hemp cultivars. Stress treatments included flood conditions; exposure to
a plant growth regulator called ethephon, used to promote fruit ripening; powdery mildew; herbicide; and physical wounding. They then tested THC
and CBD content over a four-week period when the flowers matured.

"What we found over the weeks that we were sampling, the amounts of CBD
and THC went up proportionately in all of these different cultivars for
all of these different stresses," Toth said.

By week four, at harvest time, they found that nearly every plant
(except those treated with herbicide, which were nearly dead) produced
the expected ratio of CBD to THC, with high levels of CBD corresponding
to levels of THC above the 0.3% THC threshold.

The study further proves that genetics, rather than environment, determine
the THC content and CBD to THC ratios in hemp, Smart said.

More research and breeding is needed to select appropriate genetics
that lead to high CBD but low THC, and regulatory testing may be
needed earlier, before harvest and before plants reach high THC levels,
Toth said.

========================================================================== Story Source: Materials provided by Cornell_University. Original written
by Krishna Ramanujan. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jacob A. Toth, Lawrence B. Smart, Christine D. Smart, George
M. Stack,
Craig H. Carlson, Glenn Philippe, Jocelyn K. C. Rose. Limited
effect of environmental stress on cannabinoid profiles in
high‐cannabidiol hemp ( Cannabis sativa L.). GCB Bioenergy,
2021; DOI: 10.1111/gcbb.12880 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210728150330.htm

--- up 11 weeks, 5 days, 22 hours, 45 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)