Effect of Plant Density on Agronomic Characteristics of New Sunflower Hybrids in Summer Cropping

Current study was conducted to determine suitable plant density for new sunflower hybrids in second cropping. For this purpose, response of four new sunflower hybrids Barzegar, Ghasem, SHF81-90 and Farrokh to plant densities 8, 10, 12 and 14 plantm-2 was studied using factorial experiment based on randomized complete block design with four replications in Islamabade-e-Ghard Reseach Station during 2011 and 2012 cropping seasons. Results of two years variance analysis showed that plant density had significantly effect on all measured traits except harvest index. Four hybrids were also significantly different for all traits except seed number per head and harvest index. Interaction effect between plant density and hybrids was statistically significant only for 1000-seed weight. Seed yield was increased with increasing plant density, so that seed yield in 8, 10, 12 and 14 plantm-2 were 3555, 4043, 4550 and 5167 kgha-1, respectively. Among hybrids, Barzegar having more growth duration, had more seed yield (4638 kgha-1) compared to SHF81-90, Farokh and Ghasem with 4102, 4447, and 4128 kgha-1, respectively.