(a) propagating or plant propagating material of any kind; (b) harvested material, including entire plants and parts of plants, and (c) any product made directly from the harvested material. 19. For each species, the term of protection shall be fixed by the competent authority. It may not be less than 20 years for major crop species and 25 years for arboricultural species and vines. The term of protection shall start with the grant of the certificate. Chapter IV Transfer and loss of rights 20. The rights deriving from an application for a certificate or from a certificate may be transferred either in full or in part. They may give rise, either in full or in part, to the grant of an exclusive or non-exclusive license to work. The rights granted by an application for a certificate or by the certificate may be asserted against a licensee who infringes one of the limits of his license imposed under the previous paragraph. Subject to the case provided for in Article 61 below, transfer of the rights referred to in the first paragraph shall not infringe the rights acquired by third parties prior to the date of transfer. Acts comprising a transfer or a license, as referred to in the first two paragraphs, shall be recorded in writing, on pain of invalidation. 21. Any public or private legal person may, upon the expiry of a period of three years after the grant of a certificate or four years as from the date of the filing of his application, be granted a compulsory license for this certificate, in the conditions provided for in Articles 22 to 24 below, provided that, at the time of the application for such license and failing legitimate reasons, neither the owner of the certificate nor his successor in title: (a) has begun to work or has made real and effective preparations for working the breed which is the subject of the certificate in the territory of Morocco, or (b) has marketed the product that is the subject matter of the certificate in a quantity sufficient to satisfy the needs of the domestic market or (c) has worked or marketed the variety in Morocco over the past three years. 22. A request for a compulsory license shall be made to the competent court. It must be accompanied by proof that the applicant has been unable to obtain a license for use from the owner of the certificate and that he is capable of really and effectively working the plant variety. A compulsory license may only be non-exclusive. It shall be granted on specific conditions, in particular in respect of its term, scope and the amount of royalties to which it gives rise. These conditions may be amended by decision of the competent court, at the request of the owner of the certificate or the licensee.