This is a short overview on a research paper regarding the temperature responses of medical and fiber varieties cannabis.
In this study the authors have used the following medical cannabis types – HPM (Mexico), MX and W1 (Switzerland) and 4 types of fiber cannabis – Felinq 34, Kompolty (Switzerland), Zolo 11 and Zolo 15 (Ukraine). What is specific for these plants is that they come from different geographical regions.
It is reported that temperatures above 30C (86F) have negative effect on photosynthesis and growth of a high THC yielding Mexican variety (MX).
Photosynthesis is the first physiological process affected by temperature and it could affect the growth and development of the plant since there is a close relationship between plant yield and photosynthetic rate.
In order to study the effect of temperature on photosynthesis the authors have used the following temperatures: 20C (68F), 25C (77F), 30C (86F), 35C (95F) and 40C (104F) under controlled photon flux density (PPFD, 1,500 μmol m−2s−1 which is considered near optimum), humidity (55+/-5 %) and CO2 (350±5 μmol mol−1) concentrations.
The researchers have discovered that cannabis varieties differ significantly in temperature optimum and temperature range of optimum photosynthesis. The highest rate of photosynthesis was observed in the medical cannabis HPM (Mexico) in temperature range of 30 to 35C (86-95F), followed by the fiber type Zolo 11 and Zolo 15 (Ukraine) at 30C (86F). Medical cannabis W1 (Switzerland) has shown optimum photosynthesis at temperature range from 25 to 30C (77-86F). Fiber type cannabis from Switzerland (Felinq 34, Kompilty and MX) have shown optimal photosynthesis at 25C (77F).
The authors discuss that temperature preferences could be used to identify the best variety for outdoor cultivation. Also they have observed that temperature responses vary between different varieties and types (medical cannabis or fiber cannabis).