Influence of clonal variation on the efficiency of Arundo donax propagation methods

The recent growth of interest in Arundo donax L. (Giant reed) as an energy crop is due to its great vegetative vigor and high biomass productivity. This perennial rhizomatous plant is able to grow in a wide range of pedo-climatic conditions and it has been employed by man for a great number of purposes. This has promoted its worldwide diffusion, despite its sexual sterility. Field establishment represents the most expensive phase of the whole cultivation cycle, because of the high cost of the propagules. In this work three agamic propagation methods, rhizome transplantation, hydroponic cultivation, and in vitro propagation, were compared with the aim of improving their efficiency, and reducing costs and time required. We focused our attention on in vitro and hydroponic cultivation, finding clones characterized by a high response to these propagation methods. In vitro propagation is the most widespread technique adopted in the large-scale production of propagules; according to our results hydroponic cultivation also appears to be a valid and cheap propagation method, making it possible to obtain in about 2 months, vigorous plants ready to be transplanted into the field. We found a strong effect of the clone used on the success rate of the specific propagation method, suggesting that clonal selection could be particularly useful in improving the efficiency of propagation techniques, contributing to cost reduction. Evaluation of field performance of plants propagated by tissue culture is an important matter, considering the possible residual effects of hormones on plants’ growth, and the importance of first year growth for field establishment. These experiments highlighted the lower biomass production from plants obtained by tissue culture. A novel cytokinin-like hormone, meta-topolin, was tested in vitro, in a preliminary study to evaluate its possible use for A. donax L. propagation.