SUMMARY
Sunflower (Helianthus annuus L.) is economically one of the most important annual crops in the world grown for edible oil and for bio-energy purposes. Due to the high cost and the environmental concern, fertilization is among the agronomic inputs that ought to be reconsidered and further studied. The objectives of the present study were to evaluate the growth and productivity of three sunflower hybrids under several fertilization regimes. The experiment was conducted in Agricultural University of Athens according to the split-split plot design (randomized complete block) with three replicates, three main plots (inorganic, organic and untreated) and three subplots (sunflower hybrids: Neoma, P64HE39, P64LL62). Several growth and yield parameters were measured. The results indicated that Neoma was the most productive hybrid and the one which reacted better in terms of its vegetative growth in the incorporation of the organic compost. Organic fertilization had a significantly positive effect on yield and seed number of P64HE39 and P64LL62. Conclusively, organic fertilization of sunflower hybrids can result to high yields and it can be suggested as a successful practice to sunflower growers as long as the interactions between fertilization regime and hybrid are going to be taken into account.