833 PB 343 EFFECTS OF DIFFERENT DRYING METHODS AND MOISTURE LEVELS ON SOYBEAN SEED VIABILITY AND VIGOR

Abstract

Achieving the optimum moisture content for long-term seed storage usually requires that seeds be dried after receipt at a genebank. Soybean (Glycine max L.) seeds were dried using four procedures: over concentrated H2S O4, over silica gel, at 15% relative humidity (RH), or in an oven at temperatures of 30, 35 and 40C. Following dying seeds were stored at 40C for 10 days and at 5C for one yr. Seeds were evaluated for germination and vigor (root length, dehydrogenase, and leachate conductivity). Initial moisture content (mc) was reduced from 8.3% to between 6.6% (24 hr at 30C) and 4.6% (H2S O4, 30 days). Germination and vigor of seeds was essentially unchanged immediately following the drying treatments. Storage for 10 days at 40C reduced germination by up to 12% while storage for one yr at 5C had a similar effect (14% maximum loss) for most treatments. The treatments having the lowest drop in germination after one yr of storage treatment were the silica gel and the 30C oven treatments, which dropped only 3% in germination. Drying at 15% RH, also resulted in a lower loss in germination. In all three tests, vigor of seeds after storage at 40C was higher than controls for the the silica gel and 15% RH treatments as well as for the 30C and 35C oven treatments. Storage at 5C gave similar results for all three vigor assessments.