Atributos de qualidade de sementes de milho beneficiadas em mesa de gravidade

Abstract

This study was conducted to evaluate the effectiveness of the gravity table in separating seed corn into fractions of different quality, and to relate physical and physiological attributes for practical recommendations. Five lots of seed corn classified into unsized, large flat, large round, small flat and small round were conditioned through a pressure type gravity table. The original sample obtained before gravity table separation and the heavy, medium heavy, medium light and light fractions obtained from the discharge edge of the machine were analyzed for physical (bulk density, weight, volume, specific gravity, purity, and pericarp injury), and physiological (standard germination. cold germination. and field emergence) quality attributes. Original seed corn quality was upgraded by the heavy and the medium heavy fractions. The medium light fraction may be reconditioned to recover fractions of acceptable seed quality, and the light seed obtained from the low side of the gravity table did not meet the seed requirements. When the initial seed quality of a lot is high, only marginal improvement in seed quality was obtained. Bulk density was the best physical attribute of the seed corn correlated with germination. For seed corn conditioners, the “can test” is recommended to easy determine the efficiency of the machine adjustments. A difference in bulk density of 8% between extreme fractions is recommended as a pattern for quality control in the gravity table.