EFFECT OF HUMIC ACID ON THE GROWTH, YIELD COMPONENTS, AND YIELD OF THREE SUNFLOWER CULTIVARS (HELIANTHUS ANNUUS L.)AL-Abody M.A.K., Ramadhan M.N. and Muhsin S.J.Abstract A field experiment was carried out during the Spring 2020 season at Al-Huwair area, north of Basra Governorate, to evaluate the effect of sprinkling three levels of humic acid (0, 3, 6 and 9 ml l-1) on the growth and yield of three sunflower cultivars; namely Zahrat al Iraq, Aqmar, and Flamme. The Aqmar cultivars provided the highest mean of plant height, stem diameter, leaf area, head diameter, number of seeds per head, 1000 seed weight, seed yield, and percentage of oil. The point of humic acid (9) mL/L-1 gave the highest mean of plant height, stem diameter, leafy area, head diameter, number of seeds per head, weight of 1000 seeds, yield of seeds, and percentage of oil. The effect of the cultivar interaction and humic acid concentration levels was important. The Aqmar cultivar recorded the highest mean of plant height, stem diameter, leaf area, head diameter, number of seeds per head, weight of 1000 seeds, seed yield, and percentage of oil at (9) mL/L-1 concentration level. |