Allelopathic effects of wheat, soybean and oat residues on cucumber and Fusarium oxysporum f.sp cucumerinum Owen

Allelopathic effects of stubble leachates (0,12.5,25,50,100%) of soybean (Glycine max), wheat (Triticum aestivum L) and oat (Avena saliva L.) were investigated on seed germination and seedling growth of cucumber (Cucumis sativus L) and mycelial growth of F. oxysporum. These effects were expressed as allelopathic index (RI). The wheat stubble leachates of 50% concentration (RI = 0.382) promoted the seed germination of cucumber and other concentrations were less stimulatory. All concentrations of soybean stubble leachates promoted the seed germination and leachates (100%) were least stimulatory. Low concentration (12.5%) of oat stubble, promoted the seed germination of cucumber, but higher concentrations (100% and 50%) were inhibitory. Wheat stubble leachates promoted the plant height and root length at 100% concentration (RI = 0.630). Thus higher concentrations of wheat stubble leachates stimulated the seed germination and seedling growth of cucumber. The similar trend was observed in leachates of soybean stubble. Oats stubble leachates were most stimulatory at 12.5% concentration. Stubble leachates of wheat and soybean inhibited the mycelial growth of F. oxysporum at 100% and 50% concentrations, but stimulated the mycelial growth at 25% and 12.5% concentrations, respectively.