International Journal of Horticulture, 2015, Vol.5, No.21, 1-45
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group. Subcluster II contains cultivars of both spectabilis and peruviana group. The second major cluster
contained 55 varieties, contain species of glabra group and cultivars whose origin are not well recorded. The
similarity data obtained in this study agree, to some extent (at least for the buttiana group) with the previous
classification of the tested genotypes. The information obtained from this work may be useful for better
management, identification of accessions and also in avoiding duplications or mislabeling of the genotypes
studied. Present RAPD analysis was found to be very helpful for the identification of cultivars, documentation,
and to trace out the molecular affinity of origin of unknown group of
Bougainvillea
cultivars. Genetic diversity of
a large number of
Bougainvillea
cultivars has been estimated. Origin and interaction of different species/cultivars
of the four major groups were studied successfully; origin and affinity of 41 cultivars of unknown origin could be
traced out up to certain level. Such study is very helpful and necessary for assessment of genetic diversity of large
germplasm collections of horticultural species and their further improvement through selective breeding
programme (Chatterjee et al., 2007). Srivastava et al. (2009) successfully confirmed the parentage of the hybrids
and characterized 21 bougainvillea cultivars on the basis of genetic diversity through molecular markers and
morphological traits.
Palavras
(2009)
estimated genetic relationship in different bougainvillea cultivars using
RAPD.
Identification of molecular markers linked to flower vase life is an important character to improve the efficiency
of breeding programs in Carnation. 12 commercial varieties of carnation were analyzed with the RAPD technique
(Benedett et al., 2005). RAPD bands significantly discriminated a population with longer vase life.
DNA fingerprinting using mini- and microsatellite sequences was applied to identify the genotypes and to
establish the genetic distances between them in carnation and rose. The probability of two offspring from the
crossing of similar genotypes having identical DNA fingerprints (DFPs) was found to be 1.8x10
-6
for carnation
and 2x10
-8
for rose. A comparison of genetic relationships within and between categories based on known genetic
history, to genetic relationships deduced from DFPs, revealed a perfect match for both flower types (Ben-Meir et
al., 1997).
Flower doubleness as a breeding characteristic is of major importance in carnation (
Dianthus caryophyllus
), since
flower architecture is of the utmost value in ornamentals. Based on the number of petals per flower, carnations are
grouped into ‘‘single’’, ‘‘semidouble’’ and ‘‘double’’ flower types. These flower types are not easily
distinguishable due to phenotypic overlaps. Scovel et al. (1998) identified a RAPD marker which was tightly
linked to this recessive allele. The RAPD marker was cloned and used to generate a RFLP marker. This RFLP
marker could discriminate with 100% accuracy between the semi-double and double- flower phenotypes in
carnations.
Bacterial wilt is one of the most serious diseases of carnations (Dianthus caryophyllus) in Japan. This disease is
very difficult to control with chemicals once it has occurred. Breeding of resistant cultivars is considered the
optimum strategy to overcoming this disease. However, it takes over 3 months to determine the resistance of
breeding materials by inoculation assays. Onozaki et al. (2003) tested to identify RAPD markers associated with
genes controlling wilt resistance in a resistance-segregating population. Results suggest that at least 3 genes are
concerned with resistance to bacterial wilt. In particular, 4 RAPD markers identified by bulked segregant analysis
were linked to a major resistance gene. These markers should be useful for marker-assisted selection in carnation
breeding programs.
Genetic linkage map was constructed on the basis of RAPD and SSR by using a resistance-segregating population
of 134 progeny lines of carnation (
Dianthus caryophyllus
L.) that were derived from a cross between ‘Carnation
Nou No.1’ (a carnation breeding line resistant to bacterial wilt) and ‘Pretty Favvare’ (a susceptible cultivar).
Linkage analysis revealed that 124 loci could be mapped to 16 linkage groups that extended for 605.0
centiMorgans (cM) and the average interval between two loci was 4.9 cM. Quantitative trait loci (QTL) analysis
to evaluate the resistance to bacterial will suggest that resistance to bacterial wilt in carnation is related to one
major and at least two minor genes. This was the first report on the construction of a linkage map of the carnation
(Yagi et al., 2006).
.
