Five squash (Cucurbita pepo, L.) parental inbred lines were used in this
investigation in a diallel crosses to determine the general and specific combining
abilities as an attempt to establish one inbred fine or more as a tester for some
economical characters studied. The crossing procedure was carried out in Dokki, under plastic house conditions, in the growing season of 1997. The studied traits were: number of internodes to the first female flower, early yield, total yield and resistant to powdery mildew. The obtained results could be summarized as follows:- General combining ability (GCA) effects were highly significant for all studied
traits. Moreover, highly significant specific combining ability (SCA) was noted in
all studied characters. Based on the estimates of GCA and SCA of each parent, potentiality of each
parent in each individual. characters was identified. Inbred line P3 could be
relatively considered as a good combinor for the five studied characters. Inbred
line P3 had high desirable states GCA effects for all studied characters and are
recommended for breeding with lines that showed crosses with high SCA.