investigation of the relationship between grain yield and yield components in barley varieties and new hybrids using multivariate statistical methods

in order to study the realationship between genetic diversity and different characteristics associated with grain yield in barley, 28 genotypes of barley cultivars contain seven cultivars and 21 hybrids were evaluated in randomized complete block (rcb) design with three replications. cultivars were valfajr, makuei, kavir, rayhan, gorgan, nusrat and nimroz. this study was carried out in research field of islamic azad university – karaj branch during 2009 – 2010. thirteen traits including grain yield, biological yield, harvest index, 100 seed weight, stem diameter, plant height, spike length, days to heading, spike weight, awn length, peduncle length, seed length and seed diameter were studied. results identified that the correlation coefficients between grain yield and biological yield, weight spike, awn length, seed length and peduncle length were positive and significant. path analysis revealed that biological yield have the most direct and positive effect on grain yield. spike weight indirect effect via biological yield on grain yield was positive. factor analysis showed that four factors explained 70.68 percent of the total variance. the first, second and third factor called yield, morphological characteristics and seed characteristics respectively. cluster analysis according ward method grouping the genotypes into three main groups.