INFLUENCE OF MICRONUTRIENTS AND THEIR METHOD OF APPLICATION ON YIELD AND YIELD COMPONENTS OF SUNFLOWER

The sunflower (Helianthus annuus L.) has been recognized as a crop with high potentials that can successfully meet future oil requirements of the country. Formulation of micronutrients (MN) based fertilizer, in terms of application rate and method, and uptake of MN by sunflower has the ability not only to ensure nutrients availability to plants particularly in MN-limiting environments but also can manipulate the environmental hazards associated with over inorganic fertilization. To support this view, clear experimental evidence is still lacking. In addition, the current experiments aimed to evaluate the influence of MN and its method of application on yield and yield components of sunflower cultivars/hybrids. Three sunflower cultivars (HO-l, Hysun-39 and Ausigold-62) along with three MN (Z, B and Fe) and two application methods (soil and foliar) were used in the experiment. Three Zn application rate (3, 5 and 8 kg ha(-1)) along with 0.75 kg ha(-1)B and 0.30 kg Fe ha(-1) were used in four combinations such as 0-0-0, 0-0.75-0.30, 0-0.75-0.30, 3-0.75-0.30, 5-0.75-0.30, 8-0.75-0.30 kg Z, B and Fe ha(-1), respectively. A control (no MN) treatment was also included for comparison. Two year averaged study exhibited that foliar application of Zn, B and Fe at rate of 8-0.30-0.75 kg ha(-1) increased stem girth, head diameter, number of seeds head(-1), seed weight head(-1), seed index, oil content and seed yield by 21%, 27%, 13%, 34%, 19%, 24 and 31%, respectively over control. Among cultivars/hybrids, the hybrids HO-l and Hysun-39 had taller plants, seed weight head(-1), seeds head(-1) and earlier in flowering and maturity. Flowering and maturity was delayed in Ausi Gold-62 with higher seed index and oil content. It is concluded that foliar application of micronutrients at the rate of 8+0.75+0.30 Zn, B and Fe kg ha(-1) had substantially improved yield and yield related traits of sunflower cultivars HO-l, Hysun-39 and Ausi gold-62.