Study of the relationships between yield and some important agronomic traits through path analysis and factor analysis in sunflower (Helianthus annuus L.) genotypes

This study carried out to examine the relationships between effective traits and yield in 12 sunflower varieties. A randomized complete block design with three replications was used. Results of simple correlation showed that seed width, seed diameter, seed length and hundred grain weight correlations with kernel yield were significant at the 1 percent probability level. In stepwise regression analysis, seed width was the first trait entered in the model and explained approximately 67 percent of the total yield changes. Seed length and diameter of stem entered to the model after the seed width trait and a total of 88 percent total yield variation was explained. The characters entered into the regression model were used for path analysis to identify direct and indirect effects of traits on grain yield and their proportion of effect. The results showed that seed width, seed length and stem diameter had the most direct and positive effect on the yield, respectively. In this study, three independent factors encompassed 75 percent of the total variation. The first factor with 35.5 percent of the variance was mostly influenced by grain yield, plant height, leaf length and leaf width which was named the grain yield. The second factor with 26 percent of the total variation was mostly represented seed length and seed weight and named seed features. The third factor was highly affected by stem diameter, seed diameter and seed width with 13.4 percent of variance explained and was named the plant diameter.