Twelve bread wheat genotypes were evaluated at EL-Gemmeiza Agriculture Research Station during two successive seasons 2004/2005 and 2005/2006 to study general and specific combining ability for some quantitative characters in bread wheat . These genotypes and cultivars were crossed with three local wheat cultivars Gemmeiza 7 , Giza 168 and Gemmeiza 10 to produce thirty six crosses using Line xtester analysis . The traits studied were heading date , plant height , spike length , number of spikes/plant , spike weight ,number of kernels / spike , 1000- grain weight and grain yield / plant .
The genotypes (parents and crosses) exhibited highly significant variation for all traits studied indicating the presence of genotypic differences among these fifteen genotypes under investigation. The mean square of parent vs crosses were found to be highly significant for all traits studied expect spike length and spike weight which expected only significant. Further partitioning of crosses mean squares i.e., Line x tester analysis showed highly significant for all traits studied. The G.C.A. / S.C.A. ratio exceeded the unity for most traits studied expect heading date and spike length indicating that additive variance was predominantly controlling the inheritance of these traits .The parental lines 1,11 and tester Gemmeiza 10 might be selected as parental materials for wheat breeding programmes . The line number one had highest general combining ability effects for number of spikes/plant, spike length and 1000- grain weight. The lines and testers which performed good combining ability effects for grain yield were also good combiners for at the least one of the three yield components.