Simulação de danos mecânicos em sementes de milho durante o processo de beneficiamento pós-colheita.

Abstract

This paper evaluated the mechanical damage to corn seeds (Zeamays L.) submitted to different processing stages in an SPU (Seed Processing Unit), and subjected to a simulation process using the SPU-PF Simulator in an experiment conducted at the Laboratory of the Federal Institute of Pernambuco (IFPE) - Belo Jardim Campus. Four experiments were performed with Zeneca 84, AG 1051 hybrid corn seed cultivars, collected in the production field of IFPE - Belo Jardim Campus, July/2011 harvest. A different drying treatment was used for each experiment. In the first experiment, seeds were processed at the SPU of the Agronomy Institute of Pernambuco (IPA), located in Ibimirim - PE. Drying was performed at a room temperature of 25 ± 2 0 C, reducing moisture content from 24.8% (wb) to 12% (wb); Experiments I I , I I I and IV were conducted with an impact Simulator in an SPU. In experiment I I , corn seeds were artificially dried at 25 0 C, decreasing initial moisture content from 25.49% (wb) to 12% (wb), and then subjected to processing conditions simulating those found at the SPU of Ibimirim - PE; Experiments I I I and IV were similar to Experiment I I , altering drying temperature and initial moisture content. In experiment III the temperature was 35 0 C and initial moisture content was 25.81% (wb), while in Experiment IV they were 45 0 C and 25.14% (wb), respectively. In ali experiments, seeds were analyzed for physical (purity, weight of 1000 seeds, specific mass, density, porosity and mechanical damage) and physiological quality germination test, vigor test [first germination count, seedling length (shoot), seedling dry weight], electrical conductivity and germination speed index). A completely randomized experimental design with three replications was used. Corn seed processing in an SPU improved the seed lot and an increase in temperature decreased seed vigor.