The present work had the objective to study conventional and agroecological systems of onion seed production. For this, three farms with agroecological production and two conventional farmsin Candiota and Hulha Negra, Rs, were
followed . Six sampling plots were randomly marked each one with two meters over the production line. The variables studied were: bulb weight, bulb diameter, bulb number per area, number of stems per bulb, number of flowers per umbela, number of
seeds per flower, seed moisture content, seed efficiency, germination, first counting, weight of 1000 seeds, accelerated aging, speed of germination seed health. Based on the results the following conclusions were taken: The production of onion seed
by the agroecological system is economical possible and ecologically sustainable; onion seed production in conventional systems is less than 30% of its potential; we can consider that the agroecolgical and conventional production of onion seeds
have similar potential and physiologic quality; and the number of flowers per umbela is the main component of onion seed production.