International Journal of Horticulture 2015, Vol.5, No.12, 1
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10
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Table 2 The nucleotide sequence of primers used in the RAPD
analysis
Primer
Nucleotide Sequence
1
A01
5'CAGGCCCTTC3'
2
A02
5'TGCCGAGCTG3'
3
A03
5'AGTCAGCCAC3'
4
A04
5'AATCGGGCTG3'
5
A05
5'AGGGGTCTTG3'
6
A06
5'GGTCCCTGAC3'
7
A07
5'GAAACGGGTG3'
8
A08
5'GTGACGTAGG3'
9
A09
5'GGGTAACGCC3'
10
A10
5'GTGATCGCAG3'
scored as 1 or 0 (i.e., present or absent, respectively)
across all the fourteen genotypes. Bands that could not
be confidently scored were regarded as missing data.
The data matrices of Euclidean distances were analyzed
by the STATSOFT ver. 6 (2001) and similarities between
genotypes were estimated using the simple matching
coefficient (Sokal and Michener, 1958), calculated as
Sij = a+d/n where (a) is the number of positive
matches (i.e. the presence of a band in both samples),
(d) is the number of negative matches (i.e. the absence
of a band in both samples), (n) is the total number of
bands. The program generated a dendrogram, which
grouped the genotypes using unweighted pair group
method with arithmetic average (UPGMA) with the
JOINING tree clustering module.
Results
Morphological and chemical characteristics
The entire studied genotypes exhibited a high variability
for all the morphological and chemical characteristics. A
wide range of values among genotypes was recorded in
all traits.
Concerning leaf area, the percentage of variation
(maximum/minimum*100) was high with 217%.
Genotypes with Egyptian source were characterized
by high leaf area. Genotype (Copi) was the highest
genotype with 425 cm
2
more than twice the lowest
genotype (PI 518687) with 196.11 cm
2
. Also, other
Egyptian genotypes (Shmamay and Eskandrani)
ranked high for leaf area (Table 3). Regarding fruit
weight, the percentage of variation was extremely
high with 532%. The winter squash genotype
(Butternut) ranked as the first genotype for this trait
with 283.44 g. Accessions (PI 518687 and PI 518688)
which belong to acorn squash came after Butternut but
was significantly different with 153 and 147.56 g
respectively (Table 3). The group of genotypes with
which belong to acorn squash came after Butternut but
was significantly different with 153 and 147.56 g
respectively (Table 3). The group of genotypes with
Egyptian origin maintain high fruit weight compared
with other summer squash genotypes. The percentage
of variation for fruit length was relatively moderate
with 175%. The acorn squash genotypes (PI 518687
and PI 518688) had the higher fruit length followed by
the winter squash genotype (Butternut) and the
commercial genotype (Eskandrani) with none significant
difference (Table 3). The percentage of variation for
fruit firmness was moderate with 166%. Again, acorn
squash genotype (PI 518687) ranked with the highest
fruit firmness among all tested genotypes followed by
winter squash (Butternut) and genotypes with Egyptian
source (Eskandrani and Copi) (Table 3). The range for
S.S.C among tested genotypes was relatively limited with
percentage of variation as 148%. Acorn squash genotype
(PI 518688) was the highest genotype concerning S.S.C
with 5.07% but was not significantly different than the
following genotype (Butternut) with 4.98% (Table 3). The
range for ascorbic acid content among tested genotypes
was broad with percentage of variation as 520%. There
was no clear trend concerning ascorbic acid content
among tested genotypes and none of the morphotypes
showed apparent association with ascorbic acid content
(Table 3).
The results in Table (4) and Figure (1) revealed a
significant negative correlations between fruit length
and fruit weight (r = -0.39) as well as fruit firmness
and S.S.C. content (r = -0.2). However, a significant
positive correlation has been found between leaf area
and both fruit length (r = 0.46) and ascorbic acid
content (r = 0.42). In addition, a significant positive
correlation has been also found between fruit length
and ascorbic acid content (r = 0.29). Non-significant
correlation coefficients were observed among other
morphological and chemical traits (Table 4).
Molecular evaluation
This study was carried out to apply molecular tools to
assess the polymorphism existed as well as determine
the genetic relationship among 14 squash genotypes.
Ten primers which produced good and reproducible
polymorphic bands among the 14 squash genotypes
were used for further analysis. These 10 primers
produced 209 DNAfragments with 100% polymorphism
