Effect of Leaves Defoliation and Plant Density on Growth, Yield and Quality of Some Sunflower Genotypes (Helianthus annuus L., Compositae)

For maximization the productivity, quality of sunflower crop, two field experiments were conducted during two successive spring growing seasons of 2007, 2008-2008, 2009 to determine growth, yield and quality of sunflower genotypes (Helianthus annuus L.) to plant density and leaves defoliation. Each experiment comprised of three sunflower genotypes (Morden, Flame and Manon), four levels of plant density (22222, 29629, 44444 and 88888 plants.hector-1) and three levels of upper leaves defoliation (0, 4 and 8 leaves). It was conducted according to Randomized Completely Block Design with split- split plot with three replications. The results could be summarized as: Increasing plant density to 88888 plant.hector-1 led to significant increases in plant high, hollow percentage and oil percentage. The plant density at 22222 plant.hector-1 cause a significant increase in stem diameter, leaf area, head diameter, number of seed per head and weight of thousand seed, while increasing plant density from 22222 to 44444 plant.hector-1 cause a significant increase in total yield, oil, protein yield in the two growing seasons of 2007, 2008-2008, 2009, respectively