An application for a certificate of plant variety protection filed in this country based on the same variety, and on rights derived from the same breeder, on which there has previously been filed an application for plant variety protection in a foreign country which affords similar privileges in the case of applications filed in the United States by nationals of the United States, shall have the same effect as the same application would have if filed in the United States on the date on which the application for plant variety protection for the same variety was first filed in such foreign country, if the application in this country is filed within twelve months from the earliest date on which such foreign application was filed, not including the date on which the application is filed in the foreign country.