diversity and relationships of yield and quality traits in cocksfoot (dactylis glomerata l.) genotypes

Cocksfoot (dactylis glomerata l.) is an important cool season grass species in the moderate climate of iran. in order to evaluate the yield and quality traits, an experiment was conducted in irrigation conditions using 36 accessions of dactylis glomerata using a randomized complete block design with three replications in islamabad, kermanshah province, iran in 2010. characters such as forage dry matter (dm) yield and quality traits were measured. there were significant differences between genotypes for yield and all of quality traits. results of correlations between traits showed that crude protein (cp) was positively correlated with total ash and negatively correlated with both water soluble carbohydrates (wsc) and the crude fiber (cf). there were strong negative correlations between digestibility dry matter (ddm) and both acid detergent fiber (adf). using cluster analysis (ward method), the accessions were classified into five groups. factor analysis after varimax rotation revealed that three factors explained 83.63% of total variance. the first and the second factors were related to the forage quality. the third factor was correlated with dm yield. based on factor analysis and means comparisons, it was concluded that the accessions karaj197, zanjan499 and ghazvin783 were more efficient for both forage yield and quality traits than other accessions of the d. glomerata. however, accession karaj10112, russia1551, usa1715 had higher values of the quality traits but lower production. in spite of high forage yield, accessions marand 255, and karaj 10113 had a poor quality. therefore, the accessions with higher forge yield and quality indices were introduced for improving the synthetic varieties.