Polje mora biti tako obdelano in posevek na taki stopnji razvoja, da to omogoča ustrezno kontrolo pristnosti in sortne čistosti, zdravstvenega stanja in, pri koruzi, pristnosti in čistosti samooplodnih linij in preverjanje odstranjevanja metlic pri proizvodnji semena hibridnih sort.
The field shall be so cultivated and the crop at such a stage of development as to permit an adequate check of identity and varietal purity, of health status and, in the case of maize, of the identity and purity of inbred lines and of emasculation for the production of seed of hybrid varieties.