In the United States, for instance, the invention or discovery of new or improved plant varieties was clearly granted patent protection only in 1954, 160 years after the laws first appeared, In the 1970s, the U.S., Germany, the Netherlands and 14 other countries joined together to form the International Union for the Protection of New Varieties of Plants, which protects patents for new varieties in the participating countries.
例如：美國在專利法出現後的一百六十年，即一九五四年終於明文規定，發明或發現任何突變種、雜交種及新植物，均可申請植物專利。一九七○年代，美、德、荷等十七個國家也共同成立了「植物新品種保護國際聯盟」，保障參與國的品種專利。