Physiological basis of quality development in relation to compositional changes in maize seed

This study was carried out to link the understanding of changes in seed composition with the development of seed quality. Seeds from two single cross maize hybrids were harvested at eight stages over a period of about nine weeks during development in two production years under field conditions. Seed quality tests used were warm germination test for viability, accelerated ageing test for storage quality and two types of cold test (rolled towel test, tray method) for physiological quality. Proportions of starch, protein, oil, neutral detergent fibres, sucrose, glucose and fructose as well as amounts of ions leaked into water after 24 h soak in distilled water were determined for each harvest date. Maximum storage quality was attained at least one week before maximum physiological quality was attained. However the maximum level of these quality components was attained three to seven weeks before maximum seed dry weight. High seed quality was associated with high proportion of starch but low proportions of protein, total soluble sugars and K⁺.