THE EFFECTS OF SEED SIZE AND SEED DENSITY ON GERMINATION AND VIGOR IN SOYBEAN (Glycine max (L.) Merr.)

Abstract

The germinability and vigor of seeds of different sizes and densities from each of 18 soybean seedlots were tested using the standard rolled towel germination test, the single seed conductivity test, and the bulk leachate conductivity test. The largest seeds and the low density seeds performed worst in the standard germination test, although there was an indication that the viability of extremely small seeds may also be low. Single seed leachate conductivity levels were highest for large seeds and low density seeds, indicating low vigor. Bulk conductivity tests showed high levels of leakage in large seeds, but did not detect differences between seeds of high and low density. Seed size and seed density effects were usually less pronounced or non-existent in seedlots of extremely high or extremely low vigor. Furthermore, the effects of seed size and density on viability and vigor do not appear to be of sufficient magnitude to allow for significant seedlot improvement through conditioning unless cleanout percentages are prohibitively high.Key words: Soybean, seed size, seed density, germination, vigor