02825nam a2200301 a 450000100080000000500110000800800410001910000170006024501310007726000520020830000090026050000200026952020310028965000180232065000130233865000220235165000150237365000160238865000120240465000150241665000140243165000120244565000090245765300160246665300200248265300120250265300090251415632661999-04-23       1986    bl uuuu  m   00u1 u    #d1 aBORBA, C. S.  aSome relationships of seed quality and planting date to development and seed production of soybean (Glycine max (L.) Merrill).  aMississippi: Mississippi State Universityc1986  a63p.  aTese Doutorado.  aThe influence of soybean (Glycine max (L.) Merrill) seed quality on plant performance has been investigated, but previous studies did not evaluate the effects of planting date. This study was conducted to evaluate the effects of physiological quality of seed when planted on optimum and post-optimum dates on both agronomic and seed quality characteristics of early and late maturity soybean. In both 1984 and 1985, an equal or higher percentage of seedlings emerged from plots planted with higher quality seed, although emergence percentages were 20% less from the optimum date plantings than the post-optimum date plantings due to an extended of dry weather following the initial plantings. In contrast seed quality had no significant effect upon plant, height, height of lower most pod, number of barren plants, lodging or final stand in either year. Plots planted with high qality seed in 1985 produced significantly higher yields (69Kg/ha) than those planted with lower quality seed. This difference was not observed in 1984. Planting at the optimum time maximized yields of both cultivars. The viability and vigor of seed harvested from plants off each planting date and cultivar differed significantly each year. This indicated that the post-maturation, pre-harvest environment exerted a greater influence on quality of the seed produced than planting or cultivar maturity date. It was concluded that planting high quality seed will result in a higher emergence percentage of seedlings over a range of seedbed conditions than planting seed of lower quality. On the other hand, seed quality at the levels used in this study had no consistent effcts upon the agronomic characteristics measured. Further, planting during the optimum time maximized yields of both cultivars but did not necessarily result in production of good quality soybean seed. Finally, because of the influence of the post-maturaton, pre-harvest, soybean seed should be harvested at the earliest time practical regardless of cultivar or planting date.  aplanting date  asoybeans  aÉpoca de Plantio  aFisiologia  aGlycine Max  aPlantio  aProdução  aQualidade  aSemente  aSoja  aCultivation  aProduction data  aQuality  aSeed