【正文】 s. Existing members of the Union are given ?ve years to achieve this position while new members of the Union are given ten years. In respect of the accession of future members, new provisions were adopted to allow certain intergovernmental organizations to bee party to the Convention. 外文原文 二： Plant Breeders39。 ? minimum duration of protection。 in South Africa, the average maize yield has grown from 1 ton per hectare in 1950 to tons per hectare in 2020 and in wheat from tons per hectare in 1950 to tons per hectare in It is generally recognized that 30–60% of that increase, according to the crop and the location, is due to geic improvement, . After extensive preparatory work at the initiative of the French Government, a Diplomatic Conference ?nished its work on December 2, 1961, with the adoption and signature of the UPOV Convention. The following thirteen European States participated: Austria, Belgium, Denmark, Finland, Federal Republic of Germany, France, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom, together with the European Economic Community (EEC), the United International Bureau for the Protection of Industrial, Literary and Artistic Property (BIRPI), which later became the World Intellectual Property Organization (WIPO), the Food and Agriculture Organization of the United Nations (FAO) and the Organization for Economic Cooperation and Development (OECD), and the following four nongovernmental organizations: ? International Association of Plant Breeders for the Protection of Plants Varieties (ASSINSEL). ? International Association for the Protection of Industrial Property (AIPPI). ? International Community of Breeders of Asexually Reproduced Ornamental Varieties (CIOPORA), which later became the International Community of Breeders of Asexually Reproduced Fruit Tree and Ornamental Varieties (CIOPORA). ? International Federation of Seed Trade (FIS). The UPOV Convention was signed by plenipotentiaries from Belgium, France, Germany, Italy and The Netherlands and, during the following year when it remained open for signature, it was also signed by Denmark, Switzerland and the United Kingdom. In recognition of the fact that new varieties of plants are a powerful tool to enhance agricultural and overall economic development, the States party to the UPOV Convention wished to provide incentives for sustainable plant breeding. Their aim was to guarantee the moral and material rights of breeders in respect of their varieties, in accordance with clearly de?ned and internationally harmonized principles. Under the UPOV Convention, in order to obtain protection of a new variety, it is required to ful?ll the following three technical criteria: ? It must be clearly distinguishable from existing varieties. ? It must be sufficiently uniform. ? It must be stable in its essential characteristics after repeated reproduction or propagation. Furthermore, it must have a suitable denomination.‘‘Protection’’ means that any mercialization of propagating material of the variety is subject to the breeders authorization. The UPOV Convention entered into effect on August 10, 1968, when the ?rst three instruments of rati?cation were deposited by the United Kingdom, the Netherlands and the Federal Republic of Germany. This was the origin of UPOV, which chose Geneva for its headquarters. The Additional Act of 1972 The UPOV Convention provided, in its Article 27, that it was ‘‘reviewed periodically with a view to the introduction of amendments designed to improve the working of the Union’’ and that, unless the Council decided otherwise, ‘‘for this purpose, conferences shall be held every ?ve years […]’’. The ?rst revision was thus to take place in 1972. Experience had already shown that the distribution of the ?nancial burden caused by the expenses of the Union needed re?nement. According to Article 26(2), the member States were divided into three classes, corresponding to one, three and ?ve contribution units. The purpose of the Diplomatic Conference that was held in November 1972 was, therefore, to introduce a ?veclass contribution system, with a span of contributions rising continuously from one to ?ve, the Council being empowered to authorize a State, under speci?ed circumstances, to contribute half a unit only. The Additional Act entered into force on February 11, 1977. By that time, the work on a new revision of the Convention was already underway. The 1978 revision The member States of UPOV had already realized in 1973 that there was a need to revise the substantive provisions of the Convention. After extensive preparatory work under the auspices of the Council of UPOV, a Diplomatic Conference was convened in October were distributed widely and, together with the ten members of the Union, the following twentyseven nonmember States took part in the Conference:Argentina, Australia, Bangladesh, Brazil,