Allelopathic Effect of Sweet Corn and Vegetable Soybean Extracts at Two Growth Stages on Germination and Seedling Growth of Corn and Soybean Varieties

摘要

A study was conduct to assess the allelopathic effect of sweet corn and vegetable soybean on two varieties of each corn and soybean. Aqueous extracts from shoot and root of the two crops at two crop growth stages were used and compared distilled wateras control. Sweet corn and vegetable soybean shoot extract from 35 Days Old (DO) plants significantly retarded the germination of all tested varieties compared to control, but in soybean the same effect was also noticed from 60 DO plants, while 60 DO corn had variable effect on germination. Similarly, the shoot extract of 35 DO corn and soybean significantly reduced number of roots and total root length per seedling of corn varieties. The root extract of soybean and corn also retarded both number of roots and total root length, but the magnitude was lower than that of shoot effect. Sixty days old corn shoot and root extracts had stimulatory effect on number of roots and total root length of both corn varieties. On the other hand soybean shoot extractreduced number of roots per seedling as well as total root length per seedling compared to control. With regard to soybean root extract had no significant influence on the number of roots per seedling, but enhanced the total root length per seedling. Shoot extract from 35 DO soybean and corn reduced shoot and hypocotyl length of corn and soybean respectively, while root extract as well as both shoot and root extract from 60 DO plants had variable effect. Five compounds (R_f =0.80,0.70, 0.50, 0.48 and 0.40) were separated from soybean shoot and root, three (R_f = 0.84, 0.50 and 0.40) and one (R_f = 0.84) from corn shoot and root, respectively. Soybean and corn shoot extract from 35 days old plants deformed root and hypocotyl tip of corn and soybean varieties, respectively.