Future research could focus on consumer understanding of hemp food’s specific properties and improve consumer education to address the identified lack of understanding. This may be of benefit to both the hemp food industry, and the medicinal cannabis quarter. The findings also point to a potential for the development of a strain of cannabis fit for human consumption which is free from THC. While it is beyond the scope of this research and the competency of the researchers to suggest how or if this might be achieved, it would appear that innovation in food production is currently achieving goals never before imagined. Genetic modification, 3D printed foods, and foods produced using ultrasound or infusion heat treatment, for example, are highly advanced production methods for novel foods that may only be the tip of the innovation in the food production iceberg.
Based on the reduction in seed development as compared to other crossing combinations, the triploids were determined to be infertile.As far as we are aware, this research represents the first report of triploid C. sativa female infertility. Whether the infertility of the triploids directly mitigates the yield reduction by pollination was not addressed in this study, and therefore is still unknown. Further research is necessary to demonstrate the effect of infertility on the development of cannabinoids in high pollen versus low or no pollen conditions. Nonetheless, it can be speculated that infertility might improve cannabinoid yield by the following two different mechanisms: by avoiding the termination of inflorescence development and/or by avoiding reductions in cannabinoid accumulation. Similarly to Arabidopsis, C. sativa has an indeterminate inflorescence architecture, which means the inflorescences keep growing and developing additional flowers until a specific event sends a signal to halt the flowering process.
In the Arabidopsis model, successful pollination can induce AGAMOUS expression , which will trigger downstream signals to end flflowering and begin flower senescence . The triploid plants in our research showed no response to pollination, which could be a sign that the terminal flowering signals might not initiate in the triploid plants following a pollen challenge. On the other hand, seed development after pollination may alter carbon resource allocation, which might reduce the development of inflorescences and secondary metabolism synthesis. Our research showed that triploid plants rarely produced seeds following pollination, and could therefore suggest that plants will not allocate carbon resources from flower development or cannabinoid synthesis to seed development. It is also possible that neither of these physiological processes are impacted, but rather the reduction in cannabinoid content in pollinated flowers is merely due to a dilution effect of the presence of seeds, which do not contain the cannabinoid-producing trichomes. More research on the effect of infertility on cannabinoid development is warranted to further confirm the value of commercial triploid cultivars.
Although plants containing even numbers of chromosomes are generally considered fertile, reduced fertility or even infertility have been reported in other species containing even ploidies. For example, the allotetraploid, or natural tetraploid, Hibiscus acetosella ‘Panama Red’ has been reported as producing no viable seeds . Tetraploid foxtail millet cultivars displayed a two-fold reduction in fertility as compared to their diploid counterparts . Reporting the reduced fertility of tetraploid C. sativa has important implications for the hemp breeding and hemp seed industries. Our results indicate that the investment of producing triploid seeds may be higher than producing diploid seeds, due to the lower seed numbers produced in the tetraploid × diploid crosses studiedin this research.
To compensate for the reduced seed number, more intense pollination or extending the pollination period may be recommended. Furthermore, the asymmetric nature of the crosses involving the tetraploid, at least as observed in the genotypes tested in the current study, indicate that the selection and breeding of the pollen recipient as the tetraploid parent has important ramifications for the success in breeding triploid C. sativa. The unidirectional compatibility or asymmetric interploidy crossing compatibility of hemp might be caused by an asymmetric triploid block. A triploid block is a phenomenon in which seed development fails due to an imbalance in genome size and gene expression between the parents of different ploidies; in many cases, triploid block leads to abnormal development or underdevelopment of the endosperm and embryo .