Estimates of Heritability and Average Degree of Dominance by Complete Diallel Crosses Analysis in Hexaploid Wheat (Triticum aestivum L.)

Seven varieties of hexaploid wheat (Triticum aestivum L.) JAWAHIR-20, REYNA-27, ACHTAR, REBWAH-12, REBWAH-12, Ibaa 99and Abo-Gharaib and their full dialed crosses were used in this study. Grains of parental varieties and their hybrids were planted at the college of Agricultural and Forestry University of Mosul using randomized complete block design with four replications, during the growing season (2013-2014), depending on rain fed conditions. Genetical analysis was performed to determine the genetic systems for each of plant height, Number of spikes per plant, biological yield, grain yield, weight of (100) grains and number of grains per spike, and also to estimate, genetical variance components average degree of dominance, heritability. Estimation of genetical parameters ratios indicated that there were different degrees of dominance on the studied traits, and irregular distributions of dominat and receive allels among parents for all traits except for (100) grains weight. There were three groups of dominant genes controlled for (100) grains weight and one for other traits. the broad sense heritability estimate were low for 100 grains weight and height for other traits, however narrow sense heritability estimates were: low for number of spikes, grain yield, and medium for others traits. .