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PDFWAC 16-302-290

Field standards for corn seed certification.

Except for hybrid corn field standards for corn seed certification are:
(1) Corn seed isolation requirements are:
(a) An inbred must be so located that it is not less than 660 feet from other corn except when the inbred is grown as a pollinator in a single cross production field. Any ear parent(s) in the same isolated field must be entered for certification, inspected, and meet all field requirements for certification.
(b) A specific foundation single cross must be located so the seed parent is not less than six hundred and sixty feet from other corn for pollinator rows and other seed parent(s) in the same isolated field. All seed parent(s) in the same isolated field must be applied for certification, inspected, and meet all field requirements for certification.
(c) Differential maturity dates are permitted for modifying isolation distances for inbred lines or male sterile inbred line increases if there are no receptive silks in the ear or seed parent at the same time pollen is being shed in the contaminating field.
(d) Foundation inbred or single cross production fields of dent sterile popcorn need not be isolated from yellow dent field corn.
(e) Corrections for improper isolation must be made by one of the following methods:
(i) By completely destroying or by detasseling the necessary contaminating corn before silks appear in the ear or seed parent in the field to be certified; or
(ii) By completely destroying the plants which are improperly isolated from the contaminating corn before the final field inspection.
(2) For corn single crosses, nine feet is the maximum distance a seed parent row must be from a pollen parent row.
(3) For corn single crosses, the minimum population of pollen shedding plants per acre is two thousand. Ineffective pollen parent plants must not be counted.
(4) Corn single cross fields being inspected for certification must contain not less than four hundred pollen plants per acre that are actively shedding pollen when more than twenty-five percent of the seed parent silks are apparently receptive.
(5) Corn single cross detasseling or pollen control. More than five percent of the seed parent must have apparently receptive silks for the following provisions to apply. Apparently receptive silks are emerged silks which are not wilted or brown.
(a) An isolation of a specific foundation single cross is not accepted for certification if at one inspection more than one-half percent of the stalks of the seed parent have shed pollen, or if the total number having shed pollen on any three days of inspection exceeds one percent.
(b) Cytoplasmic male sterile seed parent plants; detasseling (cutting or pulling) to control plant pollen is permitted.
(6) Corn field roguing:
(a) Definitely off-type plants must be destroyed completely so that suckers do not develop. Plants showing definite hybrid vigor or a definitely different type from the inbred or parent being inspected are classified as definitely off-type.
(b) For inbred lines, an isolation in which more than one-tenth of one percent (one per one thousand) of definitely off-type plants have shed pollen, when at the same time more than five percent of the plants have apparently receptive silks, is not certified.
(c) For single crosses, an isolation in which more than one-tenth of one percent of definitely off-type plants are present in the seed parent, when the silks have turned brown, is not eligible for certification.
(d) Sucker tassels and portions of tassels of off-type plants is counted as shedding pollen when two inches or more of the central stem, the side branches, or a combination of the two has the anthers extended from the glumes.
[Statutory Authority: RCW 15.49.005, 15.49.081, 15.49.310, 15.49.370(3) and chapter 17.24 RCW. WSR 00-24-077, ยง 16-302-290, filed 12/4/00, effective 1/4/01.]
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