The influence of sward competition on shoot growth and development in Senecio retrorsus, D.C.*

Part of a thesis submitted by the senior author to the University of Natal in partial fulfilment of the requirements of the Ph.D. degree.

Abstract

In each of two seasons the growth form of Senecio retrorsus plants in Natal Tall Grassveld differed in accordance with the degree of utilization of the grasses and thus the degree of competition offered. In rested veld the main stems of seedlings and mature plants were long and spindly while those in frequently clipped veld were robust and short stemmed. The development of reproductive structures occurred earlier in plants grown in clipped veld. Judicious veld management alone is not considered a solution to the Senecio problem.

UITTREKSEL

In elk van twee seisoene het die groeivorm van Senecio retrorsus‐plante in Natal Langgrasveld vol‐gens die graad van benutting van die veld en derhalwe die mate van mededinging wat gebied is verskil. In gespaarde veld was die hoofslamme van saailinge en volwasse plante lank en skraal terwyl dié in gereeldgesnyde veld sterk en kortstammig was. Die ontwikkeling van reproduktiewe strukture het vroeër in plante in gesnyde veld voorgekom. Oordeelkundige weiveldbestuur alleen word nie as ‘n oplossing tot die Senecio‐probleem beskou nie.

Notes

Part of a thesis submitted by the senior author to the University of Natal in partial fulfilment of the requirements of the Ph.D. degree.

New address: Institute of Agronomy and Pastures, Dept. of Agricultural Technical Services, Pretoria.