CYPERUS KYLLINGIA AND CYPERUS BREVIFOLIUS: A POTENTIAL MODEL FOR THE STUDY OF ALLELOPATHY

Cyperus kyllingia and Cyperus brevifolius are problematic turfgrass weeds in Hawaii. Both are closely related weed species with similar morphology and growth characteristics. C . kyllingia appears to be a more successful weed with regards to interference than C . brevifolius . Greenhouse experiments were conducted to compare the levels of interference exerted by C . kyllingia and C . brevifolius upon Cynodon dactylon turfgrass. C . kyllingia reduced the growth of C . dactylon by about 50 %, while C . brevifolius did not significantly reduce C . dactylon growth. These results correspond with the chemical profiles of C . kyllingia and C . brevifolius . Analysis has shown that C . kyllingia contains two sesquiterpenes which have been identified as potentially allelopathic components of Cyperus rotundus . C . brevifolius contains waxes and the two sesquiterpenes found in C . kyllingia are absent. This suggests that allelopathy may be the mechanism responsible for the different levels of interference exhibited by C . kyllingia and C . brevifolius , and these species may provide an important model for the study of allelopathy.