1. (1) Unit of certification. The entire acreage of any one specific foundation single cross grown by and/or belonging to one applicant must be eligible and be inspected. Any field or portion of a field failing to meet requirements must be so disposed of that it cannot be used for seed purposes.

2. (2) Isolation requirement. A production field of a specific foundation single cross involving male sterile material must be so located that it is not less than 40 rods from any other kind of corn. In case of normal single cross seed production fields, the following exceptions will apply:

   1. (i) Adequate natural barriers for modifying isolation distances; and
   2. (ii) Differential maturity dates may permit modifying isolation distances, provided that there are no receptive silks in the ear parent at the time pollen is being shed in the contaminating field.

3. (3) Detasseling. The following requirements apply only when 5.0 per cent or more of the ear parent plants have apparently receptive silks:

   1. (i) A foundation single cross will not be accepted for certification if on any one inspection more than 1.0 per cent of the ear parent plants have shed pollen, or on any three inspections on different dates exceeds 2.0 per cent;
   2. (ii) When more than one combination is being grown in the same isolation and the ear parent of one or more of them is shedding pollen in excess of 1.0 per cent, all ear parents having five per cent or more apparently receptive silks at that time will be disqualified unless adequately isolated from the shedding ear parent;

   3. (iii) Sucker tassels, portions of tassels on main plants will be counted as shedding pollen when two inches or more of the central stem, the side branches or a combination of the two have the anthers extended from the glumes.

      (b) Specific requirements.

4. (1) An isolation in which more than 0.1 per cent definitely offtype, or more than 1.0 per cent, doubtful-type plants in the pollen parent have shed pollen, will not be certified.
5. (2) At the time of the last inspection the ear parent shall not contain in excess of 0.1 per cent definitely offtype or 1.0 per cent doubtful-type plants.
6. (3) Any plant shedding pollen in the male sterile rows must be completely destroyed.

(a) General.