PT  - JOURNAL ARTICLE
AU  - Susanne Schilling
AU  - Rainer Melzer
AU  - Caroline A. Dowling
AU  - Jiaqi Shi
AU  - Shaun Muldoon
AU  - Paul F. McCabe
TI  - A protocol for rapid generation cycling (speed breeding) of hemp (<em>Cannabis sativa</em>) for research and agriculture
AID  - 10.1101/2022.09.12.507554
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.09.12.507554
4099  - http://biorxiv.org/content/early/2022/09/14/2022.09.12.507554.short
4100  - http://biorxiv.org/content/early/2022/09/14/2022.09.12.507554.full
AB  - Hemp (Cannabis sativa) is a highly versatile multi-purpose crop with a multitude of applications, from textiles, biofuel and building material to high-value food products for consumer markets. Furthermore, non-hallucinogenic cannabinoids like cannabidiol (CBD), which can be extracted from female hemp flowers, are potentially valuable pharmacological compounds. In addition, hemp has high carbon sequestration potential due to its rapid growth rate. Therefore, the hemp industry is gaining more traction and breeding hemp cultivars adapted to local climate conditions or bred for specific applications is becoming increasingly important.Here, we present a method for rapid generation cycling (speed breeding) for hemp. The speed breeding protocol makes use of the photoperiod sensitivity of Cannabis. It encompasses vegetative growth of the plants for two weeks under continuous light, followed by flower induction, pollination and seed development for four weeks under short-day conditions and a seed ripening phase under continuous light and water stress. With the protocol introduced here, a generation time of under nine weeks (61 days) from seed to seed can be achieved. Our method furthermore synchronises flowering time of different hemp cultivars, thus facilitating crosses between cultivars. The extremely short generation time will enable hemp researchers and breeders to perform crosses in a time-efficient way and generate new hemp cultivars with defined genetic characteristics in a shorter amount of time.Competing Interest StatementThis research was partially funded by GreenLight Medicines, however the company was not involved in study design and analysis.