Physical and physiological qualities of soybean seed as affected by processing and handling

Abstract

Seed processing machines remove viable seeds from non-viable seeds and inert materials based on physical characteristics. The objective of this study was to assess the effect of each processing machine alone on the physical and physiological qualities of the soybean seeds. Seed samples of two soybean cultivars - BMX Potência RR and NK 7059 RR - were collected from five machines separately: air-screen machine, spiral separator, size grader and gravity separator. The experimental design was a completely randomized factorial, varying with the equipment, with 20 replications. Samples were assessed by germination test, accelerated aging, viability and vigor by tetrazolium test (TZ), weathering damages (TZ class 3), mechanical damages (TZ 1-8) and (TZ 6-8), stink bug damages (TZ 1-8) and weight of one thousand seeds. The air-screen machine and the spiral separator did not contribute to improve physiological quality of seeds; the size grader concentrated mechanical damages in larger sizes and stink bug damages in smaller sizes. Gravity separators showed higher quality seeds at the upper part of the machine compared to intermediate and lower parts. Mechanical damages and stink bug damages can be reduced by gravity separator and weathering damages are not eliminated by any of the machines.