Missouri Seed Improvement Association
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Corn Certification

Applications Due June 15

The general seed certification standards are basic and together with the following specific standards constitute the standards for certification of corn in Missouri.

Eligibility Requirements

  • Hybrid corn is seed to be planted for any use except seed production. It may be any one of the following:
    • Single cross, i.e., the first generation of a cross of two inbred lines, an inbred line and a foundation backcross or two foundation backcrosses.
    • A three-way cross, i.e., the first generation of a cross of a foundation single cross and an inbred line or foundation backcross.
    • A double cross, i.e., the first generation of a cross between two foundation single crosses.
    • A top cross, i.e., the first generation of a cross of an open pollinated variety and an inbred line, a foundation backcross, or a foundation single cross.
  • Foundation single cross to produce foundation backcross, double, three-way or top cross hybrids. A foundation single cross to be eligible for certification must be produced from approved inbred lines or foundation backcrosses, whose source assures their identity and is approved by the certifying agency.
  • Foundation backcross to produce double, three-way or top cross hybrids. A foundation backcross to be eligible for certification must be produced from approved single crosses and inbred lines whose source assures their identity and is approved by the certifying agency.
  • Inbred lines
    • An inbred line to be eligible for certification must be from a source such that its identity may be assured and approved by the certifying agency.
    • An inbred used as a pollinator in a foundation single cross or foundation backcross in isolation may be certified provided all the seed parents in the isolated field are inspected for certification and meet all field requirements for certification.

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Seed Source

  • Only the class "Certified" is recognized in hybrid corn.
  • Hybrid corn must be produced from certified foundation seed that has been field inspected.
  • Foundation backcrosses
    • A first generation foundation backcross shall be the first generation cross between a foundation single cross or related inbred lines and an inbred line which shall be the same as one of the inbreds in the foundation single cross.
    • A second generation foundation backcross shall be the cross of a first generation backcross (ear parent) with its recurrent inbred parent (pollen parent)
  • A foundation single cross shall consist of the first generation hybrid between two inbred lines, an inbred line and a foundation backcross or two foundation backcrosses. A fertility restoring line may be substituted for its non-restoring counterpart in a foundation single cross or foundation backcross provided the fertility restoring line is the same in other observable characteristics as its non-restoring counterpart.
  • An inbred line must be a relatively true breeding strain of corn resulting from controlled self-fertilization or a backcrossing to a recurrent parent with selection or its equivalent.
    • When a specific genetic factor(s) is added to an inbred line, the line must have been backcrossed to its recurrent parent at least five generations. The line must be homozygous for the specific genetic factor(s) except for the pollen restoration factor(s) and the genic male sterile maintainer line.
    • For a recovered pollen restorer inbred line, selection must be relative to a specific cytoplasmic male sterile source.
    • A genic male sterile maintainer line, consisting of duplicate-deficient and male-steriles in an approximate 1:1 ratio, shall be no more than two generations removed from breeder's seed. The maintainer shall be designated according to generation as:
      • Breeder's seed - the hand pollinated selfed seed from a known duplicate-deficient plant heterozygous at a particular male sterile locus.
      • Foundation I seed - the product of random-mating among fertile plants arising from Breeder's seed.
      • Foundation II seed - the product of random-mating among fertile plants arising from Foundation I seed.
    • A genic male sterile line shall be a strain homozygous for a particular male sterile recessive allele and shall be closely related to its maintainer counterpart.
    • The genic male sterile lines may be identified as to the recessive genes they carry, e.g. B37 ms-1, N28 ms-10. The maintainer lines may be identified not only for the male sterile gene for which it is heterozygous, but for the specific translocation from which it was derived, e.g. B37 Mt-1 ms-1, N28 Mt-1 ms-10.

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Land Requirements

There are no requirements as to the previous crops.

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Production of Seed

  • Field Inspection
    • One or more field inspections shall be made by the certifying agency during the pollinating period.
  • Inspection of Seed
    • Foundation single crosses, foundation backcrosses and inbred lines shall be ear inspected after maturity or grown in a winter grow-out test by the certifying agency.

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Field Standards

  • General
    • Isolation
      • Foundation single crosses, foundation backcrosses and inbred lines.
        • An increase field of an inbred line, either male sterile or fertile, or a production field of a specific foundation single cross, or a foundation backcross involving either male sterile or fertile lines must be isolated by not less than 660 feet from any other kind of corn, except, no isolation is required for the production of hand-pollinated seed.
        • In the case of foundation single cross, foundation backcross, or inbred line seed production, the following exceptions may be considered when the contaminating field is of the same color and texture.
          • Adequate natural barriers are permitted for modifying isolation distance.
          • Differential maturity dates may permit modifying isolation distances provided there are no receptive silks in the seed parent at the time pollen is being shed in the contaminating field.
          • Dent sterile popcorn requires no isolation from dent corn.
      • Hybrid Corn
        • A specific hybrid to be accepted for certification must be so located that the seed parent is not less than 660 feet from other corn of a different color and texture. However, in the case of the same color and texture or white endosperm corn -optically sorted, the distance may be reduced to not less than 410 feet and further modified by the planting of pollen parent border rows, the number of which is to be determined by the acreage of the specific cross in accordance with the following tables. Other exceptions are listed below.
Hybrid Corn
Field Size
1-20 acres 20+ acres
Min. distance from other corn (ft) (minimum) border rows
410
0
0
370
2
1
330
4
2
290
6
3
245
8
4
205
10
5
165
12
6
125
14
7
85
16
8
0
-
10

Sweet Corn
Distance of ear parent from dent corn (ft) Field Acreage of Affected Seed
10 or less
10-14
15-19
20-24
25-29
30-34
35-39
40 or more
660
645
625
610
595
580
560
545
620
600
585
570
550
540
520
500
580
560
545
520
510
495
480
460
540
520
500
485
470
450
435
420
495
480
460
445
430
415
395
380
455
435
420
400
385
370
355
340
410
395
380
365
345
330
315
295
370
355
340
320
300
285
270
255
330
315
295
280
265
245
230
215
290
270
255
240
225
205
190
175
245
230
215
200
180
165
150
130
205
190
175
155
140
125
105
90
165
150
130
115
100
85
65
50
      • When the field acerage of the affected seed/distance of ear parent from the dent corn is at least the ratio indicated in the above chart:
        • Adequate natural barriers are permitted for modifying isolation distances.
        • Differential maturity dates are permitted for modifying isolation distances, provided there are no receptive silks in the seed parent at the same time pollen is being shed in the contaminating field.
        • Dent sterile popcorn requires no isolation from dent corn.
      • Open pollinated corn
        • The acreage to be certified must be so located that it is not less than 660 feet from any other kind of corn, including pop corn and sweet corn, unless it is a field of the same variety being inspected for certification.
        • The isolation distance may be modified, depending upon the size of the certifiable acreage, by adequate natural barriers and by designating certain rows of the same variety for pollen-shedding purposes only. The minimum isolation and border requirements for corn hybrids shall apply to open pollinated corn.
        • Rows that function to provide isolation shall not be harvested for seed purposes.
  • Specific
    • Male Sterile Ear Parent: A male sterile ear parent can be used to produce certified hybrid corn seed by either of two methods.
      • Seed of the normal fertile ear parent must be mixed with the seed of the male sterile ear parent of the same pedigree either by blending in the field at harvest or by size at processing time. The ratio of male sterile ear parent seed to normal ear parent seed shall not exceed 2:1.
      • The pollen parent must involve a certified pollen restoring line or lines so that not less than one third of the plants grown from hybrid corn seed produce pollen which appears to be normal in quantity and viability.
    • Detasseling or Pollen Control: the following requirements apply only when 5% or more of the seed parent plants have receptive silks.
      • An isolation will not be accepted for certification if more than 1.0 percent of the seed parent plants have shed pollen on any one inspection or if the total for three inspections on different dates exceeds 2.0 percent.
      • When more than one combination is being grown in the same isolation and the seed parent of one or more of them is shedding pollen in excess of 1.0 percent, all ear parents having 5.0 percent or more apparently receptive silks at the time will be disqualified unless adequately isolated from the shedding seed parent.
      • Sucker tassels, portions of tassels or tassels on main plants will be counted when 2 inches or more of the central stem, the side branches or a combination of the two have the anthers extended from the glumes and are shedding pollen.
      • The detasseling (cutting or pulling) of cytoplasmic male-sterile seed parent is permitted and the crop would be certified if it meets other certification standards.
      • For Foundation single crosses, an isolation will not be accepted for certification if more than 0.5 percent of seed parent plants have shed pollen on any one inspection or if the total for three inspections on different dates exceeded 1.0 percent.
    • Other Varieties and Off-Type Plants
      • Foundation single crosses and foundation backcrosses and certified hybrids.
        • A field in which more than 0.1 percent definitely off-type plants in the pollen parent have shed pollen will not be certified.
        • At the time of the last inspection, the seed parent shall not contain in excess of 0.1 percent definitely off-type plants.
      • Foundation single crosses, foundation backcrosses and inbred lines. Any plant shedding pollen in male sterile rows must be completely destroyed at pollination time to eliminate the possibility of its seed production.
      • Inbred lines: A field which contains, at any one inspection, more than 0.1 percent of definitely off-type plants that have shed pollen or are shedding pollen when 5.0 percent or more of the plants in the field have receptive silks, shall not be certified.
      • Open-pollinated varieties: there shall not be more than 0.5 percent detectable admixture with plants of other varieties.
    • Determining final percent hybridization and genetic purity by post control testing. Final certification of seed lots of seed as determined by the certifying agency may be contingent upon determination of percent hybridization using the following methods:
      • Biochemical methods which determine the percent hybridization by identifying selfs within the seed lot by grade size.
      • Field growouts of seed from production fields or isolations by grade size.

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Seed Standards

  • Seed House or Bin Inspection
    • Foundation single crosses, foundation backcrosses and inbred lines.
      • Seed ear-inspected after maturity shall not contain in excess of 0.1 percent (1:1000) of definitely off-type or more than 0.5 percent (5:1000) of ears with off-colored or different textured kernels which would not exceed a total of twenty-five off-colored seed or different textured kernels per 1000 ears.
  • Hybrid and open-pollinated corn seed standards.
Factor Standards for each class
Foundation* Certified
Pure Seed (min)
98.00%
98.00%
Inert Matter (max)
2.00
2.00
Total Weed Seed (max)
none
none
Total Other Crop (max)
(including other varieties)
none
0.50%
Germination ** (min)
90.00%
90.00%
Moisture (max)
14.00%
14.00%
* Foundation seed standards apply only to open pollinated corn
** Minimum germination for sweet corn is 80.00%

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