council regul ec decemb provid extens term commun plant varieti respect potato commiss european commun regard treati establish european commun regard council regul ec juli commun plant varieti right articl thereof regard propos commiss recogn technic difficulti potato breed requir expenditur research activ long period comparison overwhelm major agricultur crop addit experi market shown potato varieti reveal commerci long term comparison agricultur speci requir long term research activ reason equit refund research activ fairli late stage protect comparison agricultur crop order establish legal environ conduc achiev equit refund extens initi durat commun plant varieti year case potato measur extens appli valid commun plant varieti right grant prior entri forc regul grant futur duli surrend holder termin decis commun plant varieti offic period extens reduc nation properti right respect varieti effect member state prior grant commun plant varieti allow breeder advantag varieti compar principl laid transit provis articl regul ec adopt regul articl durat commun plant varieti provid articl regul ec respect varieti potato extend year prejudic provis articl indent regul case varieti nation plant varieti grant prior grant commun plant varieti articl indent regul appli extens refer paragraph reduc longest period full year nation properti right grant effect member state respect varieti prior grant commun plant varieti articl regul enter forc dai public offici journal european commun regul bind entireti directli applic member state brussel decemb council presid yate oj regul amend regul ec oj