Weeding out variability: a proof-of-concept for producing uniform F ₁ hybrid Cannabis sativa L. using single-seed descent

Abstract

Cannabis sativa is a wind-pollinated, predominantly dioecious, and outcrossing crop associated with high levels of genetic variability even within a single cultivar. As such, seed-grown crops are often constrained by variability issues, decreasing production efficiency and product consistency. F ₁ hybrid seed technology offers great potential to address these limitations by generating genetically uniform populations from a cross of two inbred parental lines. In C. sativa, single-seed descent (SSD) is currently the most viable method to produce these homozygous parental lines necessary for F ₁ hybrid seed production. This study exemplifies the potential of SSD coupled with chemically induced sex reversion to produce fully homozygous lines and its subsequent application in creating five F ₁ hybrid accessions. Up to six rounds of SSD were performed in an 18-month period on 16 different lines, highlighting the speed of methodology. Inbreeding through XY males was most successful and offered the greatest advantages of the lines assessed. The F ₁ hybrid lines were statistically more uniform than the inbred or original lines and more vigorous than the inbred lines, with F ₁ lines increasing seed yield between 3.9% and 155% when compared to their midparents indicating the potential to exploit heterosis. Chemotype stability was achieved in some F ₁ hybrid lines, showing that seed-grown cannabinoid crops would be possible in some contexts using F ₁ hybrid methodology, paving the way for the validation of this breeding technique in field settings and highlighting a path toward commercial hybrid seed systems in C. sativa.

Acknowledgements

The authors would like to acknowledge Andrew Kavasilas for enabling this work as the industry partner of LP210200606 and for ensuring that it aligns with industry needs, as well as providing the germplasm for the inbreeding program. The authors also thank Freya Cooper and Mollie Cooper for their assistance in harvesting and data collection of the F1 hybrid assessment. This study was funded by the Australian Research Council (ARC) Linkage project LP210200606. In addition, Lennard Garcia-de Heer received a stipend from SCU.

Author contributions

Lennard Garcia-de Heer (Conceptualization, Formal Analysis, Methodology, Investigation, Writing-original draft), Jos Mieog (Conceptualization, Methodology, Investigation, Resources, Supervision, Writing-review & editing), Adam Burn (Methodology, Investigation, Writing-review & editing), Matthew Nolan (Investigation, Writing-review & editing), Lei Liu (Methodology, Investigation, Writing-review & editing), Stephen Siazon (Investigation, Writing-review & editing), and Tobias Kretzschmar (Conceptualization, Resources, Supervision, Funding acquisition, Project administration, Writing-review & editing)

Data availability

The data that support the findings of this study are available from the corresponding author (T.K.) upon reasonable request.

Conflicts of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary material

Supplementary material is available at Horticulture Research online.

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