International Journal of Horticulture 2015, Vol.5, No.12, 1
-
10
1
Research Article Open Access
Genetic Diversity and Relationship in Squash Using Morphological, Chemical
and Molecular Analyses
Abd El-Hamed K. E., Elwan M.W.M. , Mohamed F.H
Department of Horticulture, Faculty of Agriculture, Suez Canal University, Ismailia, 41522, Egypt
Corresponding author email:
International Journal of Horticulture, 2015, Vol.5, No.12 doi: 10.5376/ijh.2015.05.0012
Received: 18 Jun., 2015
Accepted: 05 Aug., 2015
Published: 23 Sep., 2015
Copyright
© 2015 El-Hamed et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Abd El-Hamed K. E., Elwan M. W.M. and Mohamed F. H., 2015, Genetic Diversity and Relationship in Squash Using Morphological, Chemical and Molecular
Analyses International Journal of Horticulture, 2015, Vol.5, No.12 1-10 (doi
Abstract
Germplasm characterization is an important link between the conservation and utilization of plant genetic resources. A
collection of thirteen summer, spaghetti and acorn squash (
Cucurbita pepo
L.) and one winter squash (
Cucurbita moschata
L.)
germplasm accessions were screened using morphological (leaf area, fruit weight, fruit length, fruit firmness), chemical [Soluble
Solids Content (S.S.C.), ascorbic acid] and molecular [Random Amplified Polymorphic DNA (RAPD)] analyses. A wide range of
variability among genotypes was recorded for morphological and chemical characteristics. The percentages of variation were 217%,
532%, 175%, 166%, 148%, 520% for leaf area, fruit length, fruit weight, fruit firmness, S.S.C, ascorbic acid content, respectively.
Both significant positive and negative correlations have been found between the morphological and chemical characteristics. The
RAPD analysis produced 209 DNA fragments with 100% polymorphism in two or more squash genotypes while none of the
fragments showed monomorphic behavior among squash genotypes. At a similarity level of 82% the genotypes were divided into two
clusters. The first cluster consisted of eight genotypes (PI 506466- PI 292014- PI 518688- PI 615119- PI 136448- Butternut- Copi-
Eskandrani). The second cluster contained only two genotypes (Yellow Crookneck and Shamamy). When the cluster analysis of
RAPD patterns was associated with morphological and chemical evaluation of squash genotypes used in this study, there was a
notable degree of agreement. The RAPD-PCR was found to be suitable for use with squash due to its ability to discriminate between
genotypes and determine their genetic relationship. Results obtained in this investigation provide clear evidence that there is a
considerable variation among summer squash genotypes. Present results support the development of breeding programs in squash
since high genetic variability in its accessions and landraces has been found.
Keywords
Cucurbita pepo
L.;
Cucurbita moschata
L.; RAPD; Genotypes characterization; Phylogeny; Clusters.
Introduction
To increase germplasm usefulness for breeders,
morphological and molecular characterization is
needed. Morphological markers were useful in
distinguishing between ecotypes and identified a high
degree of phenotypic variability between populations
of several genotypes. The utility of using both
molecular and morphological markers has been
demonstrated in other species (Duran et al., 2005;
Ferguson et al., 2004; Gomez et al., 2004; Tatineni et
al., 1996).
In
Cucurbita
, many landraces cannot be assigned to a
given known morphotype; therefore, characterization
based on the use of both molecular and morphological
markers is essential for elucidating the genetic
relationships of ecotypes within this species (Ferriol et
al., 2003). In general, the use of both morphological
and molecular markers is recommended because each
data set provides complementary information with
greater power of resolution in genetic diversity analyses
(Gomez et al., 2004). The use of both morphological
and molecular markers classify genotypes better than
employing only one of them when assessing genetic
diversity (Franco et al., 2001) and phylogenetic
relationships. Both molecular and morphological markers
are also valuable for the identification of distinct
populations or genotypes for conservation, optimum
sites for germplasm collection, and ongoing changes
in the pattern of diversity over time. Additionally,
morphological and molecular markers are useful for
the evaluation and utilization of genetic resources, the
study of diversity of pre-breeding and breeding
germplasm, and for the protection of the breeder’s
intellectual property rights (Franco et al., 2001;
Newbury and Ford-Lloyd, 1997).
There are many different molecular techniques available
to address diversity-related issues. One popular molecular
assay that is based on PCR with arbitrary primers is
