Abstract
Fifteen genotypes of bread wheat in addition to the two local varieties (Sham6 and Abu-Graib3) were planted inside Mosul University under three spaces between rows (15, 25 and 35cm) using split plots system in randomized complete block design with three replications to evaluate grain yield and some of its components (plant height, number spikes, number of grains/spike, biological yield, 1000 grain weight and harvest index), and genotypic and phenotypic path coefficient analysis among grain yield and its components. The results showed that 15 cm row space gave highest means for biological yield, number spikes and grain yield. The grain yield at this row space was 59.378% and 123.422% higher than that at 25 and 35 cm row space respectively. Some genotypes significantly outperformed for larger number of traits including grain yield, came in the forefront of it MEXIPAK 65/ASFOOR-7, and Sham6 followed by the genotypes PBW343, NESMA*2/14-2//2*SAFI-3 and BT1735/ACHTAR//ASFOOR-1. It was shown that the yield/unit area had significant positive genotypic and phenotypic correlations with plant height, biological yield, number of grains/spike, 1000 grain weight and harvest index, and phenotypically with number of spikes per unit area. It was revealed from path coefficient analysis that number of grains/spike and harvest index had higher genetic and phenotypic direct effects and indirect effects through some other traits on grain yield, followed in importance by biological, this is useful in the reliability of these three traits as selection criteria for higher yield performance in breeding programs.
