Estimativa do vigor de sementes de milho através da avalia？？o do sistema radicular de plantulas

length of primary root of seedlings is used as seed vigor test of poaceae. however, besides primary root, there is a variable number of seminal roots, which could have been used. the objective of this work was to evaluate seminal root of corn seedlings as indicative of seed vigor of corn seeds harvested in different seasons and submitted to different threshing methods. to obtain lots with different qualities, ufv-m100 variety corn seeds were harvested in different seasons (experiment 1) and submitted to different threshing methods (experiment 2). in experiment 1, seeds were harvest in four seasons: when they reached water content of 25%, 10, 20 and 30 days later. in experiment 2, seed were harvested with water content of 25% and submitted to manual threshing, in manual stationary threshing and in stationary threshing. in experiment 1, mass of dry seminal roots of seedlings was reduced as harvest was delayed and they were positively correlated with emergency test in sand. in experiment 2, methods of threshing did not influence root traits and there was no correlation between them and emergence in sand. it is concluded that mass of dry seminal roots can differentiate vigor of lots harvested in different seasons, but no root trait was efficient to differentiate lots of seeds with mechanical damage variations.