Genotypic variation of spikes related traits and path analysis of grain yield in durum wheat lines

Genotypic variation of spikes’ related traits was assessed using a sample of durum wheat lines. A simple lattice experiment was carried out using 58 exotic promising lines and 6 landraces of two years cropping seasons (2006/2007 and 2007/2008) at the Agriculture Research Station of Islamic Azad University, Tabriz Branch, Iran. Plant height, peduncle length, number of node per stem, number of spikes per plant, spike length, number of grain per spike, 1000 grain weight, and grain yield were measured. Combined analysis of data for two years showed that interaction of lines × year was not significant for any of the traits. This indicates that responses of traits were identical in both years. There were also significant differences for all traits among the lines, and there was genotypic variation for these traits among durum wheat lines. Mean comparisons of grain yield showed that exotic promising lines: ARAMIDES (no.33), LC/RD (no.55) and landraces lines: YAZLIG (no.62) and YAZLIG (no.64) had the highest yield than the other lines. Estimate of correlation between traits indicates that there was significant and positive correlation between grain yield and traits such as number of spikes per plant, spike length and grain per spike. Regression and path analysis showed that the traits such as number of grain per spike, spikes per plant and spike length had positive and direct effect on yield.   Key words: Combined analysis, correlation, regression, Triticum durum.