The productivity and persistence of 91 accessions of grasses, legumes and broad-leaved weeds were evaluated under young rubber at the Rubber Research Institute of Malaysia Experimental Station at Sungai Buloh near Kuala Lumpur. The species were chosen from world collections for their reported shade tolerance. Two small plot experiments were conducted from 1989 to 1990 and regular harvests were used to assess yield and persistence. The soil at the site was acidic (pH 4·7) and infertile, and light transmission declined from 65 to 20% in Expt 1 and from 90 to 50% in Expt 2.

Pattern and cluster analyses were used to allocate accessions to groups with similar yield responses. Grasses which demonstrated both high yield and persistence of yield were Brachiaria decumbens MARDI accession, B. humidicola cv. Tully and Panicum maximum cvs Gatton, Riversdale and Vencedor. High yielding and persistent legumes were Stylosanthes scabra cv. Seca and S. guianensis CIAT 184. Survival of species monitored one year after completion of the experiment indicated the good longer term persistence of grasses Stenotaphrum secundatum, Panicum laxum, Paspalum notatum, Paspalum wettsteinii, Brachiaria humidicola and Panicum maximum cv. Vencedor, and legumes Arachis repens and A. pintoi.