distinguished by their unique names e.g.‘Special Kush’,‘Jesus OG’,‘Congolese
Red’,‘Girl Scout Cookies’, etc. Many of these strains display phenotypically dis-
tinct traits, as well as unique chemotypes. Seed companies and individual breeders
have created unique combinations of marihuana strains from such crosses. This
diversity of strains can create potential confusion in the rapidly expanding medical
(and recreational) marijuana industry as there may be uncertainty regarding the
identity of a particular strain, or the possibility of a mixture of strains occurring,
each with different chemical (THC:CBD) compositions. Consequently, molecular
approaches to develop DNAfingerprints of specific cultivated medical marijuana
strains for quality assurance and strain identification is highly desirable. In addition,
knowledge of the genetic relationships between strains of different origins,
including the original sources of material (landraces), would be of great interest.
19.6 Assessing Genetic Diversity in Plants
A range of molecular approaches are available to distinguish amongst cultivars and
strains of a broad range of plant species, including those of medicinal importance
(Weising et al. 2005 ; Khan et al. 2008 ). The most commonly used methods for
analysis are RAPD (random amplified polymorphic DNA) (Brady et al. 1996 ; Faeti
et al. 1996 ; Shirota et al. 1998 ; Forapani et al. 2001 ; Patzak 2001 ; Fernandez et al.
2002 ; Hakki et al. 2003 ; Pinarkara et al. 2009 ; Kayis et al. 2010 ; Devaiah et al.
2011 ; Bagyawant 2016 ), AFLP (amplified fragment length polymorphic DNA)
(Flachowsky et al. 2001 ; Hakki et al. 2003 ; Weising et al. 2005 ; Datwyler and
Weiblen 2006 ), SCARs (sequence-characterized amplified regions) (Khan et al.
2008 ; Devaiah et al. 2011 ; Srivastava et al. 2012 ; Cheng et al. 2015 ; Bagyawant
2016 ), ISSR (inter-simple sequence repeats, or microsatellites) (Brady et al. 1996 ;
Patzak 2001 ; Fernandez et al. 2002 ; Jaske et al. 2002 ; Kojoma et al. 2002 ;
Alghanim and Almirall 2003 ; Gilmore et al. 2003 ; Vijayan 2005 ; Hakki et al. 2007 ;
Stajner et al. 2008 ; Kayis et al. 2010 ; Lata et al. 2010 , 2011 ; Perez de la Torre et al.
2012 ; Bagyawant 2016 ), SNP (single-nucleotide polymorphisms) (Gilmore et al.
2003 ; Gilmore et al. 2007 ; Mendoza et al. 2009 ; Sawler et al. 2015 ) and more
recently, GBS (genotyping-by-sequencing analysis) (Elshire et al. 2011 ; Piluzza
et al. 2013 ; Lynch et al. 2017 ). These approaches will be discussed in the context of
understanding the genetic diversity among strains ofC. sativa. More detailed
information on the specific molecular approaches to assess diversity in plants can be
found in the following Refs.: Vijayan ( 2005 ), Weising et al. ( 2005 ), Caliskan
( 2012 ), and Bagyawant ( 2016 ). Organelle DNA (chloroplast and mitochondrial)
has also been used by Gilmore et al. ( 2007 ) to differentiate between hemp and
marihuana populations.
402 Z.K. Punja et al.