Section R. 285.623.216 - Certified single cross, double cross, and 3-way hybridsRule 216.
(1) A double cross hybrid is the first generation of a cross between 2 single cross hybrids. A 3-way cross hybrid is the first generation of a cross between a single cross hybrid and an inbred line.(2) A certified double cross of 3-way corn hybrid shall be produced from foundation seed (single cross or inbreds or both) that has been produced under the inspection of the official seed-certifying agency or a seed-producing agency which is recommended by the Michigan state university agricultural experiment station and the official certifying agency and which is approved by the director of the department of agriculture.(3) All of the following isolation standards shall be complied with: (a) A crossing field shall be so located that the seed parent is not less than 660 feet from corn of a different color or texture. When the contaminating source is the same color or texture of corn, the distance can be modified by the size of the crossing field and by planting border rows of pollen parent in accordance with the following table: | Field Size in Acres |
| Minimum 9 or | | | | | | | 40 or | |
| Border | | | | | | | | |
| less | 10-19 | | 20-29 | | 30-39 | more | |
| Rows | | | | | | | | |
| Distance | 660 | 627 | | 594 | | 561 | 545 | 2 |
| (in feet) | 577 | 544 | | 511 | | 478 | 462 | 4 |
| of seed 495 | 462 | | 429 | | 396 | 330 | 6 | |
| rows | 412 | 379 | | 346 | | 313 | 290 | 8 |
| from | 330 | 297 | | 264 | | 231 | 214 | 10 |
| other 247 | 214 | | 181 | | 165 | 165 | 12 | |
| corn | 165 | 148 | | 115 | | 66 | 66 | 14 |
(b) Border rows to offset a lack of isolation distance shall be planted adjacent to the exposed side or sides of the crossing field and shall produce an abundance of viable pollen at the time the seed parent silks are receptive.(c) Insufficient isolation distance can be offset by destroying a portion of the seed parent in a manner and at a time specified by the official certifying agency.(d) Two or more hybrids may be produced in the same field if the same pollen parent is used.(4) All of the following field inspection standards shall be complied with: (a) The standards in this rule apply only when 5.0% or more of the seed parent plants have apparently receptive silks.(b) Crossing fields shall be inspected by the official certifying agency not less than 3 times during the pollinating period.(c) A crossing field is ineligible if shedders, as defined in R 285.623.215(3)(d), are more than 1.0% of the seed parent plants at any 1 inspection or if an accumulative total of more than 2.0% shedders is found on any 3 consecutive inspections.(d) Off-type plants shall be removed before pollen discharge.(e) Corn that is harvested from crossing fields which are found to be ineligible for certification shall not be sold for seed purposes.(5) Both of the following seed inspection standards shall be complied with: (a) Samples for moisture and germination determination shall be furnished to the official certifying agency after the seed has been dried and shelled by the producer.(b) Seed shall have a minimum germination of 90.0% and a minimum purity of 99.0%.Mich. Admin. Code R. 285.623.216