EFFECT OF DEFOLIATION ON YIELD OF MAIZE (Zea mays L.)

Abstract

The experiment was conducted to evaluate the effect of defoliation on grain and fodder yield of maize at the research field and laboratory of Crop Physiology and Ecology Department, Hajee Mohammad Danesh Science and Technology University, Dinajpur–5200, Bangladesh during the period of December 2018 to June 2019. It was followed randomized completely block design with seven treatments and three replications. The experimental treatments were T1–Control (without leaf removal), T2–Defoliating all leaves except ear and adjacent two leaves above the ear at 7 days after silking (DAS), T3–Defoliating all leaves except ear and adjacent two leaves above the ear at 14 DAS, T4–Defoliating all leaves below the ear at 7 DAS, T5–Defoliating all leaves below the ear at 14 DAS, T6–Detopping except two leaves above the ear at 7 DAS and T7–Detopping except two leaves above the ear at 14 DAS. Light intensity in the crop canopy was increased (66.9 to 81.05%) when only lower leaves (T5) or both upper and lower leaves (T2) were removed, but when only the upper leaves (T6) were removed it was not increased. SPAD value was increased (13.58 to 24.5%) but number of leaves and leaf area plant-1 were reduced ((60.5 to 63.09% and 64.4%) due to defoliation. Substantial amount of green fodder was obtained (0.776 Kg m-2 ) due to defoliation of maize. Grain yield of maize was reduced (5.56 to 21.83%) due to different defoliation treatments but the yield reduction was not significant when only lower (T4) or upper (T7) leaves were removed and it was significant when both upper and lower leaves (T2) were removed. Reduction in grain yield due to defoliation was contributed mainly by reduction in grains row-1 , grains cob-1 , grain size, and single cob weight. Finally, substantial amount of green fodder was obtained due to defoliation of only lower or upper leaves of maize without significant grain yield reduction