Study of genetic variation in durum wheat germplasm for some morphological and agronomic characteristics

A set of 108 durum wheat accessions, selected from different origins; Turkey, Italy and Mexico, were evaluated for genetic variation for some morphological and physiological characteristics. A field experiment was conducted at Karaj in 1997-1998. The characteristics under investigation were spike yield, awn length, number of grain number per spike, peduncle length, plant height, spike length, spikelet number per spike and 1000 kernel weight. Analysis of variance showed that durum wheat from different origin were significantly different for most of the characteristics. Significant correlations were found between mean spike yield and number of grain no. per spike, 1000-kernel weight and number of spikelt per spike. The results of multiplot linear regression and path analysis indicated that 94% of variation in spike yield is explained by 1000 kernel weight, grain number per spike and spikelet number per spike. The direct effect of number of grain number per spike and 1000-kernel weight on mean spike yield were positive and significant, but the effect of number of spikelet per spike on mean spike yield was indirectly through number of grain per spike. Therefore, number of grain per spike and 1000-kernel weight were the most important components measured and it is concluded that yield improvement in durum wheat would be possible by selection for these characteristics.