Effect of glyphosate used as a sugarcane chemical ripener in Cte dIvoire

Increasing Sugar Content in Source for Biofuel Production Using Agrochemical and Genetic Approaches at the Stages of BioMass Preharvesting and Harvesting

In order to optimize biofuel (including bioethanol) production processes, various problems need to be solved, such as increasing the sugar content of raw materials/biomass to gain a higher yield of the product. This task can be solved in several ways, with their own advantages and disadvantages, and an integrated approach, such as using a combination of ripening agents and phytohormones or application of a superabsorbent polymer with at least one sugar-enhancing agent, can be applied as well. Here, we reviewed several methods, including pre- and postharvest factors (light, temperature, partial replacement of potassium with magnesium, etc.), genetic modifications (traditional breeding, phytohormones, etc.), chemical ripening methods (Ethephon, Moddus, etc.), and some alternative methods (DMSO treatment, ionic liquids, etc.). The aim of this review was to provide a comprehensive, up-to-date summary of methods of increasing the carbohydrate level in plants/biomass for bioethanol production.

Glyphosate applied at a hormetic dose improves ripening without impairing sugarcane productivity and ratoon sprouting

The management of sugarcane ripening is essential to ensuring the supply of high-quality raw material for the sugar-alcohol industry; chemical ripeners are frequently used to accelerate sucrose accumulation in the stalks during harvesting. The potential ripening effect of a low dose of glyphosate was evaluated in sugarcane, along with its impact on productivity and sprouting in the next crop cycle. A field experiment was conducted in 2015 and 2016 using a randomized block design with eight replicates in a split-plot scheme, with the following treatments: (1) control with only water application, (2) glyphosate at a low dose of 1.8 g a.e. ha-1 (corresponding to 0.005 L ha-1 of the commercial product (cp)), and (3) glyphosate at the commercially recommended dose for a ripener at 180 g a.e. ha-1 (corresponding to 0.50 L ha-1 of the cp) applied at 60, 45, 30, and 15 days before harvest (DBH). The harvest was performed on May 25, 2016 (0 DBH), and a total of five periods were evaluated. This study showed that the application of a hormetic dose of glyphosate to stimulate sugarcane ripening is promising, despite the limited duration of the effect. The application of the hormetic dose (1.8 g a.e. ha-1) at 30 DBH improved the technological quality of sugarcane in terms of Brix% juice, pol% cane, purity% juice, moisture% cane, reducing sugars, total reducing sugars, and total recoverable sugar. Additionally, it increased pol productivity, and did not affect ratoon sprouting in the subsequent cycle. Thus, this study provides a strategy for ripening management with a low environmental impact for sugarcane producers through a low (hormetic) dose of glyphosate.

Hormetic effect of glyphosate persists during the entire growth period and increases sugarcane yield

BACKGROUND

Stimulation of plant growth by low doses of a toxic compound is defined as a hormetic effect. Exposure of plants to low doses of glyphosate can cause stimulatory effects on growth or other variables. Sugarcane is the major biofuel and sugar-production crop cultivated in Brazil, but its expansion to new areas is limited; therefore, there is a demand for new technologies to improve sugarcane production per unit area. The use of pesticides to stimulate growth through the hormetic effect might be a suitable strategy to increase sugarcane yields. The purpose of this research was to investigate the effect of a low dose of glyphosate on metabolic compound accumulation, leaf phosphorus (P) concentration, and morphological variables across a one-year sugarcane cycle, as well as to determine whether the glyphosate effect was sustained and effective in improving the yield and technological quality of the sugarcane at harvest.

RESULTS

The application of a low dose of glyphosate led to higher concentrations of shikimic acid and quinic acid, higher leaf P concentrations, and improved plant growth, yield, and technological quality of the sugarcane, by increasing the Brix% juice, pol% cane, total recoverable sugar, tons of culms per hectare, and tons of pol per hectare, relative to the results for an untreated control.

CONCLUSIONS

The increased growth stimuli, observed through several variables, promoted an improvement in sugarcane yield. Therefore, the application of a low dose of glyphosate to sugarcane is a promising practice for crop management. © 2020 Society of Chemical Industry.