International Journal of Horticulture, 2015, Vol.5, No.21, 1-45
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across 15 species using AFLP markers with near-infrared fluorescence-labeled primers. A total of 733 AFLP
fragments were detected, of which 497 were polymorphic (67.8%). The 34 cultivars were separated into four
clusters. Their study established the genetic relationships of commonly cultivated calatheas, provided genetic
evidence supporting that
C. fasciata
,
C. orbifolia
,
C. rotundifolia
,
C. insignis
, and
C. ornate
were independent
species, and raises a concern over genetic vulnerability of cultivars in cluster I because of their close genetic
similarities (Kishimoto et al., 2003).
Laura (2002) applied RAPD analysis on a large number of embryogenic Cyclamen genotypes callus in order to
study the variability related to the different 2,4-D concentrations and exposure times. Twenty-five random primers
produced 161 reproducible bands. Six primers produced band patterns that differed among the samples. The four
cell lines used in the experiments were divided into two groups showing different phenotypic and molecular
behaviour. In one cell line, a different RAPD patterns observed in the callus grown at the higher 2,4-D
concentration. RAPD analysis appeared to be a useful tool for the early screening of genetic variation during
callus culture, and allowed precocious selection of the most stable embryogenic cell lines.
Silver-stained AFLP was applied to detect the genetic relationships among 83 Calycanthaceae accessions,
including 76 genotypes from C. praecox and 7 accessions from the other species. Eight primer combinations
yielded a total of 387 polymorphic bands, with an average of 48.4 per assay. The results obtained with the analysis
of genetic similarities among accessions according to Jaccard’s similarity coefficient and the clusters constructed
based on the UPGMA indicated that: (1)
Chimonanthus zhejiangensis
was highly differentiated from the other
species and detected the closest relationship with
C. salicifolius
, which possibly supported that C. zhejiangensis
was a distinct species rather than the synonym of C. nitens. Besides, C. praecox was much more closely related
with
Chimonanthus campanulatus
than the other species. (2) Extensive genetic differentiation existed among C.
praecox genotypes. However, the clusters did not match well with the floral morphological characters, perhaps
conforming that the floral phenotypic characters (flower type and size, medium and inner tepal color, and medium
tepal shape) of C. praecox were quantitative traits controlled by multi-genes rather than qualitative traits. In
addition, the results also demonstrated AFLP markers were useful for evaluating the genetic relationship among
species in Calycanthaceae and the genetic variation of C. praecox genotypes, and may serve as efficient
fingerprinting technique for further identification and classification of germplasms (Zhou et al., 2007).
RAPD markers were used to assess genetic diversity in three species of toxic larkspurs (
Delphinium
spp). A total
of 184 plants from 22 accessions were analyzed by 23 RAPD primers that amplified 188 reproducible bands. They
detected 144 polymorphic bands; 10 shared by
Delphinium glaucum
and
Delphinium occidentale
, eight shared by
Delphinium barbeyi
and
D. glaucum
, and 18 shared by
D. occidentale
and
D. barbeyi
. Thirteen bands were
specific for
D. occidentale
, 18 for
D. glaucum
and 19 for
D. barbeyi
. There were 58 bands that were specific for
individual accessions and 44 bands that were common to all three species. Some of the species-specific bands
were cloned and tested in Southern hybridization. Based on the presence or absence of the bands and dendrogram
the genetic relationships among these three tall larkspur species was generated Li et al. (Li et al., 2002).
Lee et al. (2005) studied 55 interspecific hybrids between
Dianthus giganteus
and
D
.
carthusianorum
using
RAPD markers. They detected 216 polymorphic RAPD bands and found that mostly the interspecific hybrids
exhibited intermediate characteristics between parents. Scoevel (Scoevel, 1998)identified RAPD marker which
was linked to recessive allele of ‘single’, ‘semi double’ and ‘double’ flower type of carnation (
Dianthus
caryophyllus
).
Plants regenerated from tissue culture techniques show a wide range of variability, ranging from temporary
changes in the phenotype to sexually heritable mutation. Changes in DNA methylation has been hypothesized as
an underlying mechanism of tissue-culture-induced mutagenesis which includes a high frequency of quantitative
phenotypic variation, activation of transposable elements, heterochromatin-induced chromosome breakage events,
and sequence changes due to deamination of 5-methylcytosine to thymine (Kaeppler et al., 2000). Tissue culture
techniques have been widely used for mass production in superior varieties of
Phalaenopsis
and
Doritaenopsis
(Park et al., 2002, 2003); however, the occurrence of somaclonal variations among regenerants is a frequent and
