180 W. A. VENDRAME AND A. A. KHODDAMZADEH
and hybrids for both conservation and production purposes. Yam and
Arditti (2009) provide a detailed account on the history of orchid seed
germination from the very first early attempts.
Today, in vitroasymbiotic germination of orchid seeds is a routine
procedure among orchid growers. The media used for orchid seed ger-
mination depends on the species and their particular requirements, as
well as personal preferences of growers and/or researchers (Paek et al.
2011). The most common media used forin vitroorchid seed germi-
nation are Knudson (Knudson 1946), VW (Vacin and Went 1949), MS
(Murashige and Skoog 1962), and Hyponex (Kano 1965).
Despite advances inin vitroasymbiotic germination, some orchid
seeds may be difficult to germinate and therefore require different cul-
ture media and environmental conditions. This can be the case of
some terrestrial orchids that are not necessarily in commercial pro-
duction, but that with some well-developed germination system could
become new selections for specialized nurseries. Some studies have
been performed with terrestrial orchids, includingCypripedium acaule
(St-Arnaud et al. 1992),Platanthera integrilabia(Zettler and McIn-
nis 1992, 1994), Calanthe discolor(Miyoshi and Mii 1995),Dacty-
lorhiza incarnata(Dijk and Eck 1995),Goodyera pubescens(McKin-
ley and Camper 1997),Spiranthes odorata(Zettler and Hofer 1997),
Cypripedium macranthos (Miyoshi and Mii 1998),Encyclia boothi-
ana(Stenberg and Kane 1998),Platanthera leucophaea(Bowles et al.
2002),Platanthera praeclara(Sharma et al. 2003),Comparettia falcata
(Pedroza-Manrique et al. 2005), andHabenaria macroceratitis(Stewart
and Kane 2006), among others. Kauth et al. (2006, 2008a, 2011) devel-
oped some detailed studies onin vitroseed germination and environ-
mental requirements forCalopogon tuberosus,anorchidnativetothe
United States.
SomeDendrobiumorchids are propagatedviaseed, thus offering eas-
ier, faster, and more economic means of propagation, in addition to pro-
viding virus-free seedlings to growers (Kuehnle 2007). Paek et al. (2011)
describes a protocol forin vitroasymbiotic seed germination ofPha-
laenopsisorchids using Hyponex media with modifications specific for
each stage of the process including seed germination, protocorm forma-
tion, growth and development, and seedling establishment. A number
of Asian terrestrial orchid species are also propagated viain vitroasym-
biotic seed germination, and protocols have been described for them,
including species in the generaCalanthe,Cymbidium,Cypripedium,
andPaphiopedilum(Lee 2011). Bustam et al. (2014) compares symbi-
otic and asymbioticin vitrogermination of temperate Australian ter-
restrial orchids, including protocols forCaladenia latifolia,Caladenia