Influence of Maize Seed Size/Shape, Planted at Different Depths and Temperatures on Seed Emergence and Seedling Vigor

摘要

Variation in seed size and shape along the maize cob often raises this question that which one is better in terms of seed germination and seedling establishment. The widespread belief among farmers is that large and flat seeds germinate faster and produce larger seedlings than other sizes or shapes. Thus the current study was aimed to determine the influence of maize seed size/shape, planting depth and temperature on seed emergence and seedling vigor. For this purpose, a laboratory experiment was conducted during 2012 year at Seed Technology Research Unit in Mansoura, Dakahlia Governorate, Field Crops Research Institute, Agricultural Research Center, Egypt. The treatments comprised of six levels of seed size/shape (large round, large flat, medium round, medium flat, small round and small flat) of maize hybrid single cross 131 (SC131), three levels of planting depth (2, 4 and 6 cm) and three levels of temperature (20, 25 and 30°C). From the results, seed size/shape, planting depth and temperature showed significant effect on seed germination indexes such as seed emergence percentage, mean emergence time, shoot length, root length and seedling dry weight. For instance, germination indexed increased with increasing seed size, however; increase in planting depth significantly reduced the germination indexes. By contrast, the maximum values were obtained when seed germinate at 30°C. The interaction between seed size/shape, planting depth and temperature showed a significant effect on seed emergence percentage and seedling vigor, except for seedling dry weight. Although, the effect of seed size/shape was not significant on seed emergence percentage at a depth of 2 cm and 30°C, a significant effect was observed at the depth of 4 and 6 cm. The large seeds (whether flat or round) produced the best values through the different planting depths and temperatures. The lower in seed emergence and seedling vigor of round seed than flat one is evident in small and medium seed size, when planted at deeper depths and lower temperatures. The diversity of influences on maize seed quality between flat and round shapes is corresponding with unfavorable conditions.