The aim of this study was to determine the effect of seed size and shape on germination characteristics of SC701 maize at different temperature regimes. Seeds were grouped according to shape and size and germinated using constant (30ºC and 20ºC), and two alternating (30/20 and 15/20ºC; 12/12hrs) temperatures. A factorial experiment arranged in completely randomized design with three replications was used. Highly significant differences (P < 0.001) were observed for daily germination percentage, germination rate, mean germination time, germination velocity index and vigor index. Germination rate, and germination velocity index showed that flat seeds germinated faster than round seeds at constant temperatures while, small seeds germinated faster than large seeds. A similar trend was observed for vigor index which was higher in the small and flat seeds having a higher vigor index than large and round seeds. However, the vigor index was higher at the alternating temperature (20/30ºC) than at constant temperatures in all seed groups. Highly significant differences (P < 0.001) were observed in the root: shoot ratio, seedling dry mass and fresh mass. Small seeds had higher germination speed than large seeds. Higher temperatures (30ºC constant and 20/30ºC) were associated with better germination. It is concluded that the temperature regime has a major influence on seed morphology and its seed quality parameters. These findings are useful for selection of seed size and determination of soil temperature conditions to grow maize under field conditions.
2015 by The Crop Science Society of Japan