الفهرس 
MATERIALS AND METHODSOnly 14 pages are availabe for public view
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Abstract
watermelon , Citrullus Lanatus thump , is considered one of the most favorable and common vegetables crop grown in Egypt .
The main objectives of this investigation were to determine the amounts of heterosis over the mid parents and the better parent , genetic parameters , nature of gene action , heritability in both broad and narrow senses and correlation among pairs of studied traits. The genetic material used in the present investigation included five parental varieties of watermelon .
These parental varieties were : Giza-1 (P1 ) , Giza-21 (p2 ) , Charleston gray (P3 ) , Crimson sweet (P4 ) , Dulzera ( P5 ) . All these parental varieties representing a wide range of variability for most studied traits . In the summer season of 2005 , all parental varieties were crossed among them to obtain 10 F1 hybrids and their 10 F1r reciprocal hybrids through complete diallel crosses mating design .
In addition , the five parental varieties were also self-pollinated to obtain enough seeds from each variety . In the summer season of 2006 , all 25 genotypes ( included five parental varieties , 10 F1 hybrids and 10 F1r hybrids) obtained from the last season were evaluated in a field trial experiment .
These experiments were at El-Baramoun Station , Vegitable Research station , Mansoura , Dakahlia Governorate , Egypt . The data were recorded on the following traits : Vegetative and earliness traits : plant Length In centimeters ( p.l. cm ) number of leaves per plant (No. L. / P. ) number of branches per plant (No.B./P. ) fresh weight per plant in grams (F.W./P. gs) dry weight per plant in grams ( D.W. / P. gs ) date of first male flower ( D1st F.M.F. ) date of first femal flower ( D1st F.F.F. ) Yield and yield component traits : number of fruits per plant ( N.F./P. ) total yield per plant in kilogram (T. Y. /P. kg) total yield per plot in kilogram ( T. Y. /Ptkg ) average fruit weight in kilograme ( A.F.W.kg) fruit length in centimeters ( F. L. cm) fruit diameter in centimeters (F. D. cm ) shape index ( sh. I. ) the result of this investigation presenred evidence about the presence of heterosis in watermelon . Adeditive and non_additive genetic variance including dominance in addition to cytoplasmic genetic factors contributed in the inheritance of studied traits . Finally , it could be mentioned that the possibility of producing hybrids in watermelon . plant breeders would design programs to use the superior (promissing ) F1 hybrids with high yielding and more earlier to select superior inbred lines in the advanced segregating generations.