The objective of this research was to evaluate the effect of seed physiological quality on the grain yield in isolated soybean plants. The experiment was conducted at the "Eliseu Maciel" Agriculture College (FAEM/UFPel) using the Mercedez soybean cultivars. This study evaluated two levels of seed physiological quality, high and low. A randomized complete block experimental design was used with eleven replications. The physiological quality levels were obtained from seed lots with 90% germination and 69% vigor, using the emergency period test as crition and the seedlings emerged up to the 6th day after sowing were considered as derived from seeds with high physiological quality and 9 and 10 th days from low quality seeds. In the experiment six seeds were sown per hill plot and after emergence they were thinned to one plant per hill plot based on treatment (high or low physiological quality). In order to evaluate the effect of physiological quality on individual plant development and to prevent competition between plants, 0.50 m spacing was used between the rows and between plants in the row. The number of ramifications/plants and the weight of a thousand seeds were not affected by the seed physiological quality. The plants from seeds with high physiological quality showed greater plant height, stem diameter and grain yield 25% higher than the seeds with low physiological quality.
soybean; seed physiological; yield
