Estimate of seed vigor of corn through of evaluation of root system of seedlings/Estimativa do vigor de sementes de milho atraves da avaliacao 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. Key words: primary root, seminal roots, vigor. O comprimento da raiz primaria das plantulas e usado como teste de vigor de sementes de poaceas, no entanto, alem da raiz primaria, existe um numero variavel de raizes seminais, as quais tambem poderiam ser usadas. Com este trabalho, objetivou-se a avaliacao das raizes seminais de plantulas de milho como indicativo do vigor das sementes colhidas em diferentes epocas e submetidas a diferentes metodos de debulha. Para obter lotes de diferentes qualidades, as sementes da variedade de milho UFV-M100 Nativo foram colhidas em diferentes epocas (experimento 1) e submetidas a diferentes metodos de debulha (experimento 2). No experimento 1, as sementes foram colhidas em quatro epocas: quando atingiram o teor de agua de 25% e 10, 20 e 30 dias depois da primeira colheita, em delineamento inteiramente casualizado, com quatro repeticoes. No experimento 2, as sementes foram colhidas com teor de agua de 25% e submetidas a debulha manual, em debulhador estacionario manual e em debulhador estacionario, no delineamento inteiramente casualizado, com cinco repeticoes. No experimento 1, a massa seca das raizes seminais das plant