Effect of Artificial Defoliation in Different Levels on Agronomic Characteristics in Corn Culture

The objectives of the present work were to evaluate the effects caused by defoliation at different levels in the corn crop, evaluating the agronomic characteristics and yield of maize. The experiment was conducted in the period from September to January, harvest 2016/2017. The experimental design was a randomized block, consisting of five treatments composed of different levels of defoliation of corn plants with four replicates: T1: Witness, without defoliation of plants; T2: Removal of all leaves of the plant; T3: leaves only in the lower third of the plant; T4: Leaves only in the middle third of the plant; T5: Leaves only in the upper third of the plant. Defoliation procedures were performed at the beginning of the VT reproductive stage of maize. The following parameters were evaluated: Spike insertion height; Diameter of the stem; Ear length; Spike diameter; Number of rows of grains on the spike; Number of grains in row; Final Productivity; Weight of a thousand seeds. The results were significant in almost all analyzed variables, where superior results were obtained by the T1 control, followed by T4. It was concluded that the best results were obtained by the control in which there was no defoliation, but there was no significant difference with the results obtained by the treatment in which there were only leaves in the middle third of the plant. From these results it can be affirmed the great importance of the median leaves above and below the spike insertion.