DIALLEL CROSSING AMONG BREAD WHEAT CULTIVARS FOR GRAIN YIELD AND YIELD COMPONENTS

Diallel crossing was performed among six wheat (Triticum aestivum L.) genotypes (Fateh, A3103, M2, IPA 99, A4.10 and Abu-Ghraib 3) at the Experimental Farm of Field Crops Department, College of Agriculture, University of Baghdad, during 2001-2003 seasons. The objective was to cross wheat cultivars to estimate gene action and several genetic parameters for grain yield and yield components. In the first season, a set of 15 hybrids were made. Hybrid yield trials were conducted during second season using a randomized complete block design with three replications of 21 entries. Significant differences were found among genotypes, general and specific combining ability and heterosis in all the studied characters. The cross (A4.10xFateh) produced higher number of spikes /plant (20.86spikes), which did not differed from the crosses (A4.10xAbu-Ghraib 3) and (A3101xM.2). The higher number of grains/spike (86.10 grains) was produced form the cross (A3103xA4.10), which did not differe significantly from the crosses (M.2xA4.10) and (fateh x IPA99). The cross (IPA99xAbu-Ghraib 3) was superior in 500 grains weight (56.70g). The higher grain yield (23.93 gm/plant) was produced from the cross (A3101xM.2), which did not differe from the crosses (Fateh x M.2) and (A3103 x IPA 99). The broad sense and narrow sense heritabilities differed as to different characters. The highest degree of dominance was found in the number of grains/spike. The results of this experiment revealed that superior crosses could be used to develop new promising pure lines of cultivars via selection schemes on segregants.