Effect of planting pattern and plant density on growth and yield of sunflower (Hisun-36 hybrid)

Planting pattern and plant density affect growth characteristics and yield of sunflower via changes in space available for growth of each plant. To evaluate these effects in sunflower cv.، Hisun-36 hybrid، an experiment was conducted in the spring 2006 at The Agricultural Research Station، Isfahan University of Technology، using a split-plot layout within a randomized complete block design with three replications. Row distance (60 and 75 cm) was the main plot and plant distances over the row (12، 14، 16، and 18 cm) were the sub-plots. Plant height and stem diameter were significantly increased، as row distance increased. Dry weights of stem and leaves per unit area، seed and biological yield per unit area and harvest index were decreased as row distance increased، but these decreases were only significant for dry weight of leaves and seed yield per unit area and harvest index. Stem diameter and head diameter were significantly reduced and plant height was significantly increased as planting distance decreased. Dry weights of stem and leaves per unit area were significantly increased، but seed yield per unit area and harvest index were significantly reduced as planting distance decreased. The results obtained in this experiment indicate that the combination of 60 cm row distance and 14 cm between plants (11. 9 plants m-2) might be suitable for production Hisun-36 hybrid under the conditions similar to this study.