In order to evaluate the effects of seed size on germination and seed vigor of two
soybean cultivars, an experiment was carried out at seed technology laboratory of Islamic Azad
University of Tabriz in 2008. This experiment was arranged out as factorial, based on CRD design
with four replications. Treatments were three seed sizes (small, medium and large) and two soybean
cultivars (Williams and TMS). Results showed that medium seeds had higher germination
percentage than that for large and small seed sizes..Highest and lowest amount of root and shoot
length, seedling length, and seedling dry weight belonged to medium and small seeds, respectively.
But there was not a significant effect of seed size on germination rate