13.2 Strategies Used for the Propagation ofCannabis
SativaL.
13.2.1 Conventional Propagation
Propagation through seeds and vegetative cuttings are the most common and
popular methods of cultivatingCannabis. Seeds has been the choice of starting
material by many researchers for conducting growth and physiological studies
(Quimby et al. 1973 ; Lisson et al. 2000 ; Yoshimatsu et al. 2004 ), in vitro studies for
regeneration (Slusarkiewicz-Jarzina et al. 2005 ; Plawuszewski et al. 2006 ; Wieglus
et al. 2008 ) and production of secondary metabolites in vitro (Itokawa et al. 1977 ;
Feenay and Punja 2003 ; Flores-Sanchez et al. 2009 ; Wahby et al. 2013 ) and in vivo
(Vogelmann 1988 ; Meijer et al. 1992 ).
Different methods have been adopted for seed germination. Seeds are generally
planted in moist aerated soil and photoperiod of 18 h of coolfluorescent lights is
used for establishment of seedlings (Chandra et al. 2013 ). Whereas, (Plawuszewski
et al. 2006 ; Wieglus et al. 2008 ) used DARIA ind medium for planting seeds,
Wahby et al. ( 2013 ) have used moist Whatmanfilter paper as induction medium.
Optimum seed germination temperature is reported 21–26 °C with a photoperiod of
12 h by Feenay and Punja ( 2003 ), Slusarkiewicz-Jarzina et al. ( 2005 ) and
Plawuszewski et al. ( 2006 ). Wieglus et al. ( 2008 ) and Wahby et al. ( 2013 ) have
used dark conditions for seed germination. Different cultivars ofCannabisshow
different germination response with optimal germination within 4–7 days (Weiglus
et al. 2008 ). Although, propagation by seeds inCannabisis a predominant tech-
nique, however, it is impossible to maintain the elite cultivar/clone by seed and
growing from seeds result in a large portion of crop being male plants. Since,
female plants of this species contain higher levels of THC/CBD than male plants,
cultivation of female plants is preferred. Most of the researchers so far have used
seedling parts (cotyledon, epicotyl, hypocotyl and radicle), to initiate the propa-
gation studies, however, researchers at the University of Mississippi (Chandra et al.
2010 ), have screened and selected clones and have used, nodal segments containing
axillary buds, from the mother plant for conventional or in vitro studies since it
upholds genetic uniformities among the clones.
13.2.2 In Vitro Propagation
Tissue culture technology has emerged as a promising biotechnological tool for
multiplication and genetic enhancement of medicinally important plants. ForC.
sativa, the in vitro propagation has superiority over conventional methods of
propagation not only because of high multiplication rate and production of disease
free elite plants but also overcoming the problems of heterozygosity due to its
allogamous nature. Although, in vitro techniques have been employed forCannabis
13 Micropropagation ofCannabis sativaL.—An Update 287