Neighbour effects between two co-occurring rice species, Oryza sativa and O. glaberrima.
The effects of spp. coexistence in a plant community on the interactions between plants were studied using 2 strains each of O. sativa and O. glaberrima grown during 1979 in mixture-diallel and substitutive experiments under different water conditions. Neighbour effects on growth performance differed with the strain combination and the water regime; lowland strains were stronger competitors than upland strains. In mixtures of the 2 spp. collected from the same field, O. sativa was more strongly competitive than O. glaberrima under wet conditions, but less so under dry conditions. The competitive relationship was reversed by water regime particularly in mixtures of upland strains. Lowland sympatric strains showed a relative yield total >1, suggesting avoidance of competition.