Notwithstanding the provisions of section 1441 of this title, beginning with the 1964 crop—

(1) Price support for wheat accompanied by domestic certificates shall be at such level not less than 65 per centum or more than 90 per centum of the parity price therefor as the Secretary determines appropriate, taking into consideration the factors specified in section 1421(b) of this title.

(2) Price support for wheat accompanied by export certificates shall be at such level not more than 90 per centum of the parity price therefor as the Secretary determines appropriate, taking into consideration the factors specified in section 1421(b) of this title.

(3) Price support for wheat not accompanied by marketing certificates shall be at such level, not in excess of 90 per centum of the parity price therefor, as the Secretary determines appropriate, taking into consideration competitive world prices of wheat, the feeding value of wheat in relation to feed grains, and the level at which price support is made available for feed grains.

(4) Price support shall be made available only to cooperators: and, if a commercial wheat-producing area is established for such crop, price support shall be made available only in the commercial wheat-producing area.

(5) Effective with respect to crops planted for harvest in the calendar year 1966 and any subsequent year, the level of price support for any crop of wheat for which a national marketing quota is not proclaimed or for which marketing quotas have been disapproved by producers shall be as provided in section 1441 of this title.

(6) A “cooperator” with respect to any crop of wheat produced on a farm shall be a producer who (i) does not knowingly exceed (A) the farm acreage allotment for wheat on the farm or (B) except as the Secretary may by regulation prescribe, the farm acreage allotment for wheat on any other farm on which the producer shares in the production of wheat, and (ii) complies with the land-use requirements of section 1339 of this title, to the extent prescribed by the Secretary. Effective with respect to crops planted for harvest in the calendar year 1966 and any subsequent year, if marketing quotas are not in effect for the crop of wheat, a “cooperator” with respect to any crop of wheat produced on a farm shall be a producer who does not knowingly exceed the farm acreage allotment for wheat. No producer shall be deemed to have exceeded a farm acreage allotment for wheat if the entire amount of the farm marketing excess is delivered to the Secretary or stored in accordance with applicable regulations to avoid or postpone payment of the penalty, but the producer shall not be eligible to receive price support on such marketing excess. No producer shall be deemed to have exceeded the farm acreage allotment for wheat on any other farm, if such farm is exempt from the farm marketing quota for such crop under section 1335 of this title. No producer shall be deemed to have exceeded a farm acreage allotment for wheat if the production on the acreage in excess of the farm acreage allotment is stored pursuant to the provisions of section 1379c(b) of this title, but the producer shall not be eligible to receive price support on the wheat so stored.