Physiological maturity effects on seed quality, seedling vigour and mature plant characteristics of maize in a tropical environment.

Abstract

Kernel dry matter accumulation, milk line and black layer formation which are regarded as indices of physiological maturity were compared and effect of maturity on viability and seedling vigour was investigated. Pattern of dry matter accumulation in the two hybrids used for the study was similar. The indices gave different estimates of the time physiological maturity was attained in the two hybrids. Cubic regression equations gave more realistic estimates than linear and quadratic ones, 41 and 48 days after silking in Oba Supa 1 and Oba Supa 2, respectively. Performance of seed of Oba Supa 1 harvested at 45 days after silking and with seed dry weight less than maximum, was better in laboratory and field investigations than that harvested before and after this time. There was no significant maturity-stage effect on viability of seeds. But seeds harvested before full maturity, irrespective of kernel dry weight, germinated faster, having significantly lower emergence indices than those harvested at full maturity. The rate at which seedlings accumulated dry matter during the first 30 days after planting in the field was closely related to seed dry weight.