Mode of gene aclion for some economical traits in squash was examined by 4 x 4
dialiel crossing using two American squash varieties as well as two local varieties. All
these varieties belong to the species Cucurbita pepo L. All 16 entries, which included
4 parents and 12 F, hybrids were evaluated at Experimental Station, Faculty of
Agriculture, Mansoura University. Data were recorded on plants within plots on
thethree types of economical traits (vegetative, earliness and yield traits). The
obtained results revealed that the meal' squares of gerotypes and its components.
GCA, SCA and reciprocal effects were highly significant for all studied trails, indicating
additive and non-additive genetic variance in addition 10 cytoplasmic genetic factors
contribuled In the inherilance of sludied traits. Also the results showed that the average means of the F, hybrids. F" reciprocal
hybrids and the average overall hybrids (F, ") were exceeded their mid parents (MP)
for all studied traits except for sex ratio and days to first female flower, which were
desirable lower forward increasing in female flower and earliness, respectively
Allhough, White Bush is the best combiner among this set of varieties for vegetative
traits. Eskandarani variety was Ihe best combiner among the studied set for earliness
and total yield traits. Most pairs of traits exhibited negative genotypic and phenotypic correlations
coefficient. while the following pairs of traits showed positive and significant
correlations: sex ratio (SR) with days to the first female nower (DFFF); position of the
first female flower (NFFF) with days to Ihe first female flower (DFFF); early yield
rNF7P/P and NF7P/P) with lotal yield (TNF/P and 1WF/P). Therefore, it seemed that
selection for improving one or more of these traits would improve the others. Therefore, plant breeders would design programs, which make use of these
advantages to select superior lines from the advanced segregating generations of the
high yielding F1 hybrids.