Despendoamento em Linhagens Tropicas de Milho: reflexos na produtividade

Abstract

During corn seeds hybrid production, detasseling, which consists on tassel removal from female plant prior to pollen emission, a commonly performed practice to ensure control over corn plant crosses. This operation was historically carried out manually, however, due to a series of factors, it had been replaced by mechanical detasseling. When the detasseling is carried out no damaging the leaf area, it can cause positive interferences in the final production, due to photoassimilates be translocated to compose ear´s grain, when eliminated a drain (tassel). On the other hand, the removal of upper leaves, mainly during the mechanized detasseling, could reduce yield due to high plant sensitivity at this vegetative stage when losing a photosynthetically active area. The objective of this study was to identify and quantify the effect caused by detasseling in tropical corn inbreds. The experiment was carried out in Paracatu-MG region, during the summer and winter seasons, between 2015 and 2016. Ten tropical inbreds representative of portfolio were evaluated in two treatments (detasseling and non-detasseling), quantifying variables important for seed production such as: (PRD) yield in kg/ha, (PMS) thousand seed weight in kg and (SSU) seed saleable unit at 80,000 kernel /ha. The coefficients of variation (CV) of the analyzes were low, showing a good experimental accuracy, demonstrating that when leaving only 2 leaves above the ear during the detasseling, it reduced in 19,3% PRD (kg/ha), 1,8% PMS (kg) and 17.7% SSU/ha. Defoliation is a critical factor during the detasseling process, negatively interfering in yield and directly affecting production cost, encouraging researches for process improvements or alternative methods.