Closing the Yield Gap for Cannabis: A Meta-Analysis of Factors Determining Cannabis Yield

Abstract

Until recently, the commercial production of Cannabis sativa was restricted to varieties that yielded high-quality fiber while producing low levels of the psychoactive cannabinoid tetrahydrocannabinol (THC). In the last few years, a number of jurisdictions have legalized the production of medical and/or recreational cannabis with higher levels of THC, and other jurisdictions seem poised to follow suit. Consequently, demand for industrial-scale production of high yield cannabis with consistent cannabinoid profiles is expected to increase. In this paper we highlight that currently, projected annual production of cannabis is based largely on facility size, not yield per square meter. This meta-analysis of cannabis yields reported in scientific literature aimed to identify the main factors contributing to cannabis yield per plant, per square meter, and per W of lighting electricity. In line with previous research we found that variety, plant density, light intensity and fertilization influence cannabis yield and cannabinoid content; we also identified pot size, light type and duration of the flowering period as predictors of yield and THC accumulation. We provide insight into the critical role of light intensity, quality, and photoperiod in determining cannabis yields, with particular focus on the potential for light-emitting diodes (LEDs) to improve growth and reduce energy requirements. We propose that the vast amount of genomics data currently available for cannabis can be used to better understand the effect of genotype on yield. Finally, we describe diversification that is likely to emerge in cannabis growing systems and examine the potential role of plant-growth promoting rhizobacteria (PGPR) for growth promotion, regulation of cannabinoid biosynthesis, and biocontrol.

Scientific Prospects for Cannabis-Microbiome Research to Ensure Quality and Safety of Products

“…Preventive research on the photobiology of indoor production [88] can address common pathobiology problems across Cannabis growth stages under LED and HPS lighting systems. Associated meta-analyses [89] can further predict Cannabis yield or determine the mycotoxin profile in diseased plants under light stress. Contamination of Cannabis plants and products (i.e., recreational-and pharmaceutical-grades) with mycotoxigenic organisms, including species of Aspergillus, Penicillium, and Fusarium, pose serious challenges [90].…”

Sequence and annotation of 42 cannabis genomes reveals extensive copy number variation in cannabinoid synthesis and pathogen resistance genes

“…Type V plants express no cannabinoids. Despite successful breeding efforts to deliver higher cannabinoid and terpene content, plant pathogens are still a significant contributor to crop loss in cannabis production due to the lack of disease-resistant varieties (Kusari 2013; Backer et al 2019). Many jurisdictions mandate cannabis microbial safety testing targeting epiphytic and endophytic plant pathogens that have been clinically linked to aspergillosis in immuno-compromised cannabis patients (McKernan et al 2015; Remington et al 2015; McKernan et al 2016).…”

Plant Growth-Promoting Rhizobacteria for Cannabis Production: Yield, Cannabinoid Profile and Disease Resistance

“…Studies have attempted to determine which elements of cultivation and genetics contribute to cannabis yield and cannabinoid levels/composition. Cannabis yield is influenced by light intensity and plant density (Toonen et al, 2006; Vanhove et al, 2012; Backer et al, 2019). However, little research has been conducted regarding the response of yield and cannabinoid levels/composition to the application of plant-growth promoting rhizobacteria (PGPR), although research has already demonstrated the important role of PGPR on the production of many other crop species (Mabood et al, 2014; Smith et al, 2015).…”