COMPARATIVE RESPONSE OF CHROMOLAENA ODORATA AND CORCHORUS OLITORIUS TO INTRASPECIFIC COMPETITION

Chromolaena odorata and Corchorus oUtorius were grown at 5, 10, 15 and 20 plants/pot
to evaluate the response of individual plants to intraspecific competition after 10 weeks. Both
spedes showed considerable plasticity in plant height, root dry matter production and biomass
partitioning but competitive effects were significant in respect of leaf production, leaf area and
photosynthetic effidepcy (as indicated by LAR). Competitive effects were also significant with
respe!=i to shoot and total dry weights and individual plant weight (weight per plant) in C.
oIitor/us. The reduction in leaf area was greater with increasing plant density in C. ooorata whiie
C. oUtor/us showed greater reductions in leaf production and LAR. Weight per plant was reduced
significantly by 0.56 g for eacllunit increase in plant density for both species. Differences
in plant response to intraspedfic competition were dueto growth habit and physiology. These
differences have practical implications on population regulation and relative competitive ability
of these two weeds in cropping situations.