International Journal of Horticulture 2015, Vol.5, No.12, 1
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genetic diversity among
Cucurbita
landraces that are
cultivated in Egypt and they are poorly characterized
so far.
Results obtained in our investigation provide clear
evidence that there is a considerable variation among
summer squash genotypes. Present results support the
development of breeding programs in
Cucurbita pepo
since we have found high genetic variability in its
accessions and landraces.
Plant leaf area is affecting light absorption and
consequently photosynthesis. The amount and intensity of
light during the growing season have a definite
influence on the amount of ascorbic acid formed (Lee
and Kader, 2000). Ascorbic acid is synthesized from
sugars supplied through photosynthesis in plants which
Figure 2 The RAPD markers generated by primers number
1,4,7, and 9 on the tested genotypes (1: PI 506466; 2: PI
292014; 3: PI 518688; 4: PI 506467; 5: PI 615119; 6: PI 136448;
7: PI 518687; 8: PI 216032; 9: Matrouhy; 10: Butternut; 11:
Yellow Crookneck; 12: Shamamy; 13: Copi; 14: Eskandrani)
can explain the positive correlation between leaf area
and ascorbic acid content (r = 0.42). The significant
negative correlation between fruit firmness and S.S.C.
content (r = -0.2) observed in this investigation
concerning squash was also found in other crops. A
highly significant negative correlation has been detected
between fruit firmness and S.S.C. in apple (Kvikliene
et al., 2006). However, different results were recorded
in peach and nectarine (Cantín et al., 2010). The lack
of correlation between traits in such studies should
have been no surprise since these genotypes differ
genetically in many aspects. The non-significant
correlation between fruit weight and S.S.C. for squash
in this study was also observed in pepper (do Rêgo et
al., 2011) and in peach and nectarine (Cantín et al.,
2010).
Figure 3 UPGMA dendrogram of the 14 squash genotypes
based on the 10 random RAPD primers. G1: PI 506466; G2: PI
292014; G3: PI 518688; G4: PI 506467; G5: PI 615119; G6: PI
136448; G7: PI 518687; G8: PI 216032; G9: Matrouhy; G10:
Butternut; G11: Yellow Crookneck; G12: Shamamy; G13: Copi;
G14: Eskandrani
The high leaf area revealed in Egyptian genotypes is
in agreement with known knowledge concerning the
high vegetative growth of such local genotypes. The
heavy weight of fruits of winter and acorn squash
compared with summer squash are in accordance with
established information in
Cucurbita
spp. (Rubatzky
and Yamaguchi 1997). The high fruit weight of Egyptian
genotypes is due to the selection pressure performed on
such genotypes for superior fruits for long time
(El-Hadi et al., 2014). The high fruit firmness for acorn
and winter squash is due to the hard nature of fruits in such
morphotypes (Rubatzky and Yamaguchi 1997). Although,
the range for ascorbic acid content among tested
