F1 Hybrid Seed Can Enhance Cannabis Crop Uniformity and Yield

Cannabis ( Cannabis sativa ) growers seek greater crop uniformity and yield; however, use of vegetatively propagated plants has several drawbacks. There is increased interest in F 1 hybrid seed, especially for flower production. Plant growth and performance of inbred lines of the cultivars Wife (WF) and Wilhelmina (WH), produced from one to four rounds of selfing (S 1 to S 4 ), and three F 1 hybrid lines (WF S 1 × WH S 1 , WF S 2 × WH S 2 , and WF S 3 × WH S 3 ) were evaluated. As selfing increased from S 1 to S 4 , within line plant variation did not change substantially for most measures for WF, but variation progressively decreased for plant height, total shoot length and plant dry weight for WH. S 4 plants of WH were uniformly diminutive and likely exhibited inbreeding depression. F 1 hybrids between WF and WH were larger than WH plants for all measures because WH is photoperiod insensitive (autoflowering) and dwarf. Compared with WF self-lines, F 1 WF × WH hybrid lines exhibited greater uniformity, plant dry weight, flower dry weight, and percent cannabidiol and tetrahydrocannabinol. F 1 WF × WH hybrid plants were able to achieve similar height and shoot growth to WF self-lines, even though they had a dwarf parent in WH. It is likely that heterosis is responsible for the growth enhancements observed in the F 1 WF × WH hybrids. These findings indicate that F 1 hybridization can produce uniform, stable, and high-yielding cannabis plants from seed.