Effect of planting date and harvesting stage on seed quality of 'SC 701' maize under small-scale farming conditions

摘要

Matching different management practices during seasonal changes in weather conditions might improve seed yield and quality. This study focused on the interactive effect of three planting dates and maturation stages on maize seed quality. Field trials were conducted at the University of KwaZulu-Natal's research farm during two summer seasons. A split-plot design where planting date (main factor) and harvesting time (sub-plots) arranged in randomised complete blocks and replicated (x 4) was used. Seeds were harvested at milk, dent and physiological maturity stages based on its milk line and moisture content, then dried. Seed quality was evaluated using standard germination test, vigour indices and an electrical conductivity test. The interaction of planting date and harvesting stage significantly (P 0.05) affected daily germination, mean germination time, speed of germination, root: shoot ratio, thousand seed weight and seedling fresh and dry mass. Physiologically mature seeds under early- and mid-planting had the best germination performance during warmer and drier seasons, respectively. However, seed lots harvested at dent stage under favourable weather conditions gave higher seed quality than physiological mature seeds from extreme weather conditions. For optimal seed quality, harvesting at physiological maturity under early- or mid-planting is recommended.