RESUMPTION AND GROWTH OF Cynodon dactylon RHIZOME FRAGMENTS

Cynodon dactylon is considered as noxious perennial weed in agricultural or horticultural practices in Tunisia. This weed is difficult to control due to its biological features. Its high degree of competition results not only from the competition growth factors but also the emission of toxins from vegetative and underground decaying biomass. Series of experiments were conducted over three years at the High Institute of Agronomy in Chott-Mariem, Tunisia to understand the biological behavior of rhizome fragments. A new plant will develop from pieces of C. dactylon rhizomes only when the pieces have an uninjured and completely developed bud. Cynodon dactylon showed a rhizomatous system which had the major masse of rhizomes located in the upper layer. The resumption and the emergence of rhizome fragments depended on the size, the temperature and the planting depth. Short and deep rhizome fragments were unable to emerge. As the temperature went out, the growth increased. Inverse relationship could be established between length of rhizome fragments and bud resumption. Pieces of rhizomes with 1 cm long containing developed bud produced a high percentage of new plants. Also, an inverse relationship was established between planting depth and emergence. The addition of nitrogen to the culture media decreased the inhibiting effect of apical bud and improved the resumption of lateral buds. To elaborate an efficient management strategy, we should take into account these biological parameters.