• Hybrids available for planting differ in maturity earliness and kernels’ oil content and composition. On the base of maturity, hybrids are divided in 5 groups: early, middle-early, middle late and late. Sunflower seeds begin to germinate at a temperature of 8°C. Seeds are sold in package of 70.000- 75.000 seeds, which is the rate for one hectare with a weight of 4 to 6 kilograms. Seeds are dressed with insecticide and fungicide to be protected in the very early stage of growth. We suggest a rate of 8 seeds per square meter in order to have 6-7 plants at harvesting time: This rate is ideal for fertile soils with a good moisture content during the season. In worst soils the rate would be 5 plants per square meter at harvesting.
• Sunflower yield components are:
1. The number of heads per hectare.
2. The number of kernels per head.
3. Average weight of kernel.
• Because cropped sunflower produces only a head per plant, the number of plants per hectare is the most important factor for production.
• Commonly sunflower is planted with ann interrow spacing of 70 or 75 centimetres. reducing spacing down to 40-45 centimetres can increase yield of 10-20%, specially when planting hybrids of low size (not tall).