Cannabis sativa is a multi-use predominantly dioecious plant, with plant grown for food and fibre and that present with low levels of tetrahydrocannabinoids (THC), commonly referred to as industrial hemp. Cannabis sativa are annual, short-day plants that require an extended period of darkness (long nights) to initiate flowering and so are highly dependent on the environmental conditions. The time to flowering can influence many growth traits including amount of vegetative or floral biomass and architecture. However, a subset of C. sativa plants flowers regardless of the photoperiod (also termed autoflowering). This trait is thought to be regulated by multiple genes, with two different candidate genes (AUTOFLOWER1 and AUTOFLOWER2) recently reported.
This project will use forward and reverse genetics to identify and validate the genes proposed to be involved in regulating autoflowering in C. sativa. Using DNA sequencing, we found an autoflowering candidate gene that displays sequence variation in three different cultivars. Constructs have been prepared to functionally validate this candidate using a virus induced gene silencing approach. In a complementary approach, we have crossed two female plants: autoflowering industrial hemp cultivar with a photoperiod sensitive cultivar by silver thiosulphate solution and produced genetically female F1 seeds. These have been grown under four different photoperiods: 24:0 (light/dark), 18:6, 12:12 and 6:18 (light/dark). We will investigate the characteristics and segregation of the autoflowering trait, as well as generating a F2 population for mapping. This work will lead to the development of breeding tools to help design of new Hemp varieties that are better adapted to a wide range of environments.