Seed quality of early maturing soybean cultivars from different sowing dates

This work aimed to evaluate the physiological and sanitary seed qualities o f seven early maturing soybean cultivars (EMGOPA 304, EMGOPA 309, EMGOPA 31 6, EMBRAPA 1, EMBRAPA 4, Rainha and Itiquira), obtained from three sowing d ates (conventional, on Nov. 20; early, on Oct. 30; and delayed, on Dec. 30/ 1995), at Goiania, GO, Brazil. The experiment was carried out in split plot and randomized complete block design, with three replications. Physiologic al quality was evaluated by germination test in rolled paper and in sand se ed bed and by seed vigor through the tetrazolium test. Sanitary quality was evaluated by means of the Blotter test. The results showed that physiologi cal and sanitary seed qualities are influenced by the cultivars and the sow ing dates. Early sowing in October results in seed quality losses caused by the adverse environment moisture conditions and the threshing mechanical d amages, allied to the occurrence of seed pathogen infection, specially Phom opsis sojae. High threshing mechanical damages are the cause of seed qualit y losses in the delayed sowing at the end of December.