Effects of sub-doese of ripeners on coffee plants

Abstract

The use of ripeners in the sugar and alcohol sector over the air aims to optimize and reduce their application costs, but increases the risks of product drift in several non-target cultures. Thus, the objective is to evaluate the effects of sub-doses of ripeners on coffee seedlings (Coffea arabica L.), cv. Catuaí IAC144 Red. Two experiments will be carried out. In the first experiment, four types of ripeners used in the cultivation of sugar cane will be studied, evaluating the possible damage caused in the coffee culture. The products used and their respective doses and half doses will be: glyphosate (0.50 and 0.25g pc ha-¹), sulfometuron-methyl (20 and 10g pc ha-¹), ethyl-trinexapac (1.0 and 0, 5g pc ha-¹) and ethephon (0.6 and 0.3g pc ha-¹). Based on the results of the first experiment, the second will be installed, with the objective of studying the effects of increasing doses of the most harmful ripeners on the morpho-physiological characteristics of coffee seedlings. For both experiments, the experimental design will be randomized blocks, with treatments in four replications. In the first experiment, the treatments will be arranged in a 4x2 + T factorial scheme, in which the four maturing agents applied in two doses, with a control without application, will constitute the main factors, totaling 36 experimental plots (seedlings). In the second experiment, the seven treatments in four replications will result in 28 experimental plots. In both experiments, the effects of treatments will be evaluated at 15, 30, 60 and 90 days after application (DAA), when the dominant height and stem diameter will be determined, and leaf counts will be made, and the length of branches previously marked with bandages. On these same occasions, determinations of the relative levels of total chlorophyll and fluorescence of chlorophyll a (Fv / Fm) will be made in leaves taken at random in the final third of the demarcated branches and in the middle third of the leaves of this branch. At the end of the experiment, at 90 DAA, the plants will be cut close to the surface of the soil and will be determined: leaf area, dry mass of the stem and leaves. The data obtained will be subjected to analysis of variance and regression analysis, when relevant. (AU)