Whereas the list of seeds to be covered by the system described above must be drawn up in such a way as to include the species which are most widely grown at the present time ; whereas provision should however be made for the possibility of extending this system to other seeds where experience shows this to be necessary;
Considerando que la lista de semillas , que se beneficien del régimen descrito anteriormente , debe fijarse de forma que se incluyan las especies cuyo cultivo sea por el momento de mayor importancia , que conviene , sin embargo , reservarse la posibilidad de extender este régimen a otras semillas en funcion de la experiencia adquirida ;