Evaluating Growth, Biomass and Cannabinoid Profiles of Floral Hemp Varieties under Different Planting Dates in Organic Soils of Florida

Abstract

Hemp production has been permitted as a new agricultural commodity in Florida and may serve as a potential rotational crop. Field trials were conducted in the Everglades Agricultural Region with multiple varieties planted at different dates. Data were collected on plant growth parameters, final biomass at harvest, and temporal cannabidiol (CBD) and Δ-9-tetrahydrocannabinol (THC) content in developing flowers. Results showed that at the United States Sugar Corporation (USSC) location, the BaOX variety had higher biomass compared to other varieties and at Everglades Research and Education Center (EREC), varieties ACDC and Cherry wine recorded the highest biomass compared to other varieties. Moreover, plant growth parameters such as plant height, canopy cover and SPAD were significantly affected by variety and planting date. Total CBD and THC content in plants increased over time for most varieties except for Early bird and Cherry abacus under second planting. There was a significantly high correlation between total CBD and THC content (R2 = 0.75 to 0.98, slope = 16.8 to 22.8). The THC content in most varieties exceeded the legal limit of 0.3% at some stage of the growing season. The results of this study indicate that the variety performance was largely affected by genetics compared to the planting date.

Temporal cannabinoids profile and biomass yield in cannabigerol dominant industrial hemp under different planting dates in southern Florida

“…Similarly, the effect of planting date was also not consistent among the locations (Figure 4). In other studies with CBD-dominant industrial hemp cultivars, we also found that the effect of location and planting date was not consistent across the cultivars (Chiluwal et al, 2023;Sandhu et al, 2022). We did not see significant location and planting date effect in most of the tested cultivars possibly due to similar environmental conditions during cannabinoid accumulation across all planting dates and locations in the experimental year.…”

“…Both THC (<0.1%) and CBD (<0.2%) concentration was very low in both cultivars in this study suggesting there was no or little transformation from CBGA and CBG into THC and CBD in all planting conditions and locations. Hence, the results of this study suggest that CBG‐dominant industrial hemp cultivars could be better suited in Florida's environment as most of the CBD‐dominant cultivars often exceed acceptable THC concentration (Chiluwal et al., 2023; Sandhu et al., 2022; Yang et al., 2020;). However, floral biomass yield was low in both cultivars.…”

“…THC concentration exceeding a legal threshold in CBD‐dominant hemp cultivars has become a bottleneck for hemp cultivation for essential oil production in Florida (Chiluwal et al., 2023; Sandhu et al., 2022; Yang et al., 2020). However, previous studies have only evaluated CBD‐dominant hemp cultivars and there is no information regarding the potentiality of growing CBG‐dominant hemp cultivars in Florida and similar other locations.…”

“…However, similar information regarding the effect of the environment on CBG accumulation is not available. The CBD and THC accumulation pattern over crop growing season has been documented in both CBD and THC‐dominant Cannabis cultivars (Calzolari et al., 2017; De Backer et al., 2012; Latta & Eaton, 1975; Pacifico et al., 2008; Sandhu et al., 2022; Chiluwal et al., 2023). However, CBG accumulation pattern in CBG‐dominant cultivars is still unknown.…”

“…Due to its photoperiod sensitivity coupled with comparatively shorter day length in Florida, cultivars from the northern latitude begin the reproductive phase very early in the season without accumulating much vegetative biomass in Florida's environment (Zhang et al., 2021). Similarly, most of the industrial hemp cultivars adapted in other agroclimatic conditions often exceed THC concentration above the limit (>0.3%) when grown in Florida (Chiluwal et al., 2023; Sandhu et al., 2022; Yang et al., 2020). Hence, lack of suitable cultivars with acceptable legal THC concentration and less biomass yield remains the major challenge for its commercialization in Florida and similar other climatic conditions.…”