Effect of plant density on seed yield and agronomic traits in sunflower cultivars at Shahrekord region

Sunflower (Helianthus annuus L.) is a major oilseed crop in temperate regions. In order to study the effects of genotype and plant density on seed yield and agronomic characteristics of sunflower، an experiment was conducted at the research farm، College of Agriculture، Shahrekord University، Shahrekord، Iran in 2002-2003. Four plant densities and three cultivars (Azargol، Armavirsky & Zaria) were used in a randomized complete block design as factorial experiment with four replications. The seeds were drilled in plots at row distances of 60 cm apart and 15، 18، 21 and 24 cm between plants within rows (11. 1، 9. 26، 7. 24 and 6. 94 plant per m-2، approximately). The results showed seed oil percentage was affected by genotype cultivars significantly (p<0. 01). Azargol had the highest oil percentage (47. 2%) and Zaria had the least (45. 2%) between cultivars. Oil percentage was increased when plant density increased. Plant height was affected by genotype cultivars significantly (p<0. 05)، that Azargol had the least and Armavirsky had the highest plant height. One thousand grain weight was affected by genotype cultivars significantly (p<0. 01). Zaria had the least and Azargol had the highest one thousand grain weight between cultivars. There weren’t significant differences between grain yields of cultivars; however Azargol had the highest seed yield ha-1 (2809. 9 kg ha-1). Increasing in plant density leads to higher grain yield. Oil yield was affected by genotype cultivars significantly (p<0. 05) and Azargol had the highest oil yield among cultivars. Oil yield was increased by increasing plant density. The best seed and oil yield were obtained by Azargol and Zaria with 11. 1 plant m-2. Thus based on this experiment، Azargol with 11. 1 plant m-2 is suggested for Shahrekord region. Zaria is able to change with Azargol، when there isn’t Azargol hybrid.