Parâmetros morfofisiológicos na produção do sorgo sacarino em resposta à aplicação de redutor de crescimento

Abstract

The search for renewable energy sources coupled with the need to reduce pollution drives the ethanol production. In this scenario, the sweet sorghum culture has been gaining notoriety for filling the sugarcane off-season, having good biomass production, stalks rich in fermentable sugars and a short cycle. However, the high size of the plants makes the crop susceptible to lodging, representing difficulties in harvesting and possible reduction in production. In this way, the aim of the present study was to evaluate the responses of the broth production, it’s quality, the plant morphology and lodging of sweet sorghum, cultivars BRS 511 e BRS 506, on different doses (0,75 L ha-¹ e 1,5 L ha-¹) and application times (Vegetative 5 e Vegetative 8) of the active principle trinexapac-ethyl, in order to identify the correct dosage and application season that reduces crop lodging, without significant losses in total production and quality of the broth produced. In addition, sought to understand the correlations between the morphological variables. Three trials were carried out in the city of Santa Maria - RS on the crop years of 2018/2019, 2019/2020 e 2020/2021. The analyzed variables were: total broth production (PC), soluble solids content (SS), plant height (ALT), stem diameter (DC), leaf dry matter (MSF), panicle dry matter (MSP), stem dry matter (MSC) and lodging. The data obtained were submitted to the Shapiro-Wilk test, test F and test T de Student with 5% probability, the correlation coefficients between the morphological variables were also estimated through the Pearson correlation. The application of trinexapac-ethyl with the tested dosages reduces the vegetative development of the plants, decreasing lodging and maximizing the soluble solids content of the broth, however it results in a significant drop in the total amount of broth produced, regardless of application season and grow crops. Furthermore, there is significant positive linear correlation of high magnitude among the morphological variables ALT, MSF e MSC.