ENDOPHYTIC BACTERIA OF RED-CLOVER AS AGENTS OF ALLELOPATHIC CLOVER-MAIZE SYNDROMES

The early growth effects of red clover endophytic bacteria on maize se edlings were examined in greenhouse trials. We found that endophytic b acteria from preceding clover (Trifolium pratense L.) crops can be cau sal agents of the inhibitory allelopathic 'clover-maize syndrome'. The effect was shown to be both direct (as in imbibition studies with bac terial suspensions of individual isolates) and indirect (as in leachat e studies). Imbibition or watering with the crude leachate (leachate p lus microorganisms) as opposed to filtered leachate (leachate minus mi croorganisms) derived from soil in which clover had been growing, prom pted a reduction in the rate of emergence and growth of maize seedling s (Zea mays L.) but not germination percentage. It is concluded that t he inhibitory allelopathic response in clover-maize sequences is a sid e-effect of the competition between bacteria for the same ecological n iche which usually results in temporary growth retardation. Copyright (C) 1996 Elsevier Science Ltd