In 1954, all of 160 years since patent laws were introduced, the United States specified that patent protection could be applied for in the case of all invented or developed mutant, cross-bred and new plant varieties.
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，均可申請植物專利保護。