Influence of Plant Spacing and Sowing Depth on Growth and Yield of Sunflower (Helianthus annuus L.) in Halfa Elgadidah Scheme, Sudan

In order to study the effect of plant population on growth and yield of sunflower, an experiment was conducted with complete randomize blocks design with four replications at Research Farm of Halfa Elgadidah Research Station during summer seasons of 2016 and 2017. Experimental factors including sowing depth D1, D2, D3 and D4 at (3, 5, 7 and 10 cm) and plant population where Seeds were sown in hills spaced S1, S2 and S3 corresponding to 20, 25 and 30cm apart within ridges. The results revealed that, there was a linear increase in stem, head diameter, number and seed weight per head with increase in plant spacing. Also, increasing plant density increased plant height and leaf area. The highest seed yield (3216 and 3044 kg ha-1) produced when 3 seeds of sunflower were planted at 20cm followed by the same spacing with 5 seeds per hill but the difference between them was statistically at par while 30cm plant spacing resulted in significantly less grain yield (2557kg ha-1). Hence, for achieving optimum results in sunflower variety SY40-45, the crop may be sown in plant spacing of 20 with 3 cm depth to achieve high plant population ha -1 which significantly increased seed yield per unit area.