Manipulation of gender expression in cannabis (Cannabis sativa L.)

Manipulacija izražanja spola pri navadni konoplji (Cannabis sativa L.) je povezana s hermafroditizmom, ki je genetsko in okoljsko pogojen. To lastnost lahko uporabimo pri križanju rastlin in pri pridelavi feminiziranih semen, kjer s stresnimi dejavniki na genetsko ženskih rastlinah sprožimo nastanek moških cvetov oziroma maskuliniziramo ženske rastline. Cilj magistrske naloge je bil preveriti delovanje koloidnega srebra in srebrovega tiosulfata (STS) na nastanek ženskih in moških cvetov na šestih populacijah genetsko različnih ženskih konopelj ter preveriti kalivost nastalega peloda. Izkazalo se je, da smo največji odstotek (90 %) moških cvetov na rastlino inducirali s tretiranjem z dnevnim nanosom 90 ml koloidnega srebra. Drugi največji odstotek moških cvetov je induciralo tretiranje z 0,3 mM STS (77 %). Najbolj odzivna je bila žlahtnjiteljska populacija MX-CBD-707, ki je skoraj edina tvorila kalivi pelod. Najboljši sredstvi za tvorbo kalivega peloda, ki sta pri žlahtnjiteljski populaciji MX-CBD-707 razvili kalivi pelod, sta bili 0,3 mM STS (4,8 %) in dnevno nanešeno 30 ppm koloidno srebro (2 %). Povprečni odstotek nastalih moških cvetov pri populaciji MX-CBD-707, sproženih z 0,3 mM STS, je bil 51 %. V zaključku ugotavljamo, da je za razvoj moških cvetov na genetsko ženskih rastlinah in za razvoj kalivega peloda bilo najbolj uspešno tretiranje z 0,3 mM STS, kjer je bil za uspeh predvsem ključen optimalen genotip.Manipulation of gender expression in cannabis (Cannabis sativa L.) is connected with hermaphroditism that is conditioned genetically and environmentally. This trait can be used in cannabis breeding and in the production of feminized seeds where stress factors are applied on genetically female plants to induce male flowers or so called masculinization of female plants. The goal of this thesis was to check the effect of colloidal silver and silver thiosulfate (STS) on the formation of female and male flowers on six genetically different cannabis female populations and on the germination of the developed pollen. As it turned out, the highest share (90%) of male flowers per plant was induced by treatment with daily application of 90 ml of colloidal silver. The second highest share of male flowers was induced by an application of 0,3 mM STS (77%). Almost the only and most responsive genetically female population that has produced germinative pollen was MX-CBD-707. The two most effective treatments that have produced germinative pollen on MX-CBD-707 were an application of 0,3 mM STS (4,8%) and a daily application of colloidal silver (2%). The average share of induced male flowers on population MX-CBD-707 (induced by a one time application of 0,3 mM STS) was 51%. In conclusion, we have found that the most effective treatment for induction of male flowers on genetically female plants and production of germinative pollen was an application of 0,3 mM STS, in which the optimal genotype was crucial for success