Abstract
The experiment was carried out in the Field Dept. of Hort. & Landscape Design, College of Agric. & Forestry , Mosul University , in the spring season of 2009 , to study the general and specific combining ability in F1 and F2 using Full-Diallel Cross of four varieties in summer squash viz, 1-local (Molla Ahmed) , 2-Syrian (Al-Mostkabil) , 3-Tala and 4-Bather Elbethor and their hybrids application Randomized Complete Block Design (R.C.B.D) with three replications.
The results showed that general combining ability in F1 was significant for plant height , mean fruit length and diameter , and for most of the studied characters in F2 , while specific combining ability was significant for all the studied characters except mean fruit diameter in F1 , and for most of the studied characters in F2. The reciprocal effect was significant for most the studied characters in F1 and F2. The results showed that general combining ability was higher than specific combining ability for mean fruit length and diameter in F1 and F2 it can be predicted an additive gene action for these characters. General combining ability indicated that the parent 1-Local (Molla Ahmed) and the parent 4-Bather Elbethor in F1 and the parent 2-Syrian (Al-Mostkabil) in F2 was significant consider as the best combiner for the desirable characters. The hybrids varied for their specific combining ability effects as a result of the wide genetic variation between the parents.
