Section 100. Corn certification standards; hybrids, foundation single crosses and inbred lines

A. General standards. The general standards as adopted in this chapter are basic and apply to corn.

1. Definition of terms:

a. Hybrid corn is seed to be planted for any use except seed production. It may be any one of the following:

(1) Single-cross. The term "single cross" means the first generation hybrid between two inbred lines.

(2) Double-cross. The term "double cross" means the first generation hybrid between two single crosses.

(3) Three-way cross. The term "three-way cross" means a first generation hybrid between a single cross and an inbred line.

b. Foundation single cross. The term "foundation single cross" means a single cross used in the production of a double cross, a three-way or a top cross. A foundation single cross to be eligible for certification shall be produced from approved inbred lines whose source assures their identity and is approved by the certifying agency.

c. Inbred line. The term "inbred line" means a relatively true-breeding strain resulting from at least five successive generations of controlled self-fertilization or of back-crossing to a recurrent parent with selection, or its equivalent, for specific characteristics. To be eligible for certification, inbreds shall be from a source such that its identity may be assured and approved by the certification agency.

2. Classes of seed recognized.

a. Only the class "certified" is recognized in hybrid corn. Hybrid corn shall be produced from seed that has been grown under conditions that insure its purity and trueness to type and shall be approved by the certifying agency. Proof of the restoring ability of the line shall be supplied by the originator.

b. A Foundation single cross shall consist of the first generation hybrid between two inbred lines to be used in the production of double, three-way or top crosses. A fertility restoring line may be substituted for its nonrestoring counterpart in a foundation single cross provided the fertility restoring line is the same in other observable characteristics as its nonrestoring counterpart.

B. Land requirements. There are no requirements as to previous crops.

C. Field standards.

1. Field inspection. One or more inspections shall be made by the certifying agency during the pollination period.

2. Isolation.

a. Foundation single crosses and inbred lines.

(1) An increase field of an inbred line, either male sterile or fertile, or a production field of a specific foundation single cross involving either male sterile or fertile lines shall be isolated by not less than 220 yards from any other kind of corn, except no isolation is required for the production of hand pollinated seed.

(2) Adequate natural barriers and differential maturity dates are permitted for modifying isolation distance for both inbreds and single crosses provided there are no silks in the seed field at the time pollen is being shed in the contaminating field.

(3) Single crossing plots shall be isolated by at least 440 yards from sweet corn, popcorn or open-pollinates of other colors.

b. Hybrid corn.

(1) A specific hybrid to be accepted for certification shall be so located that the seed parent is not less than 220 yards from other corn of a different color or texture. However, in the case of the same color and texture that distance may be 206 yards 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 table. Other exceptions are listed in subdivisions (2) and (3) below.

When the number of acres in the crossing field is:								Then this minimum number of border rows of male parent is required:
9 or less	10-14	15-19	20‑24	25-29	30-34	35-39	40 or more
And the distance of the female or seed rows from other corn in yards is:
220	214	209	203	198	192	187	181	0
206	200	195	189	184	178	173	167	1
192	187	181	176	170	165	159	154	2
178	173	167	162	156	151	146	140	3
165	159	154	148	143	137	132	126	4
151	145	140	134	129	124	114	110	5
137	132	126	121	115	110	104	99	6
124	118	112	107	101	96	90	85	7
110	104	99	93	88	82	77	71	8
96	90	85	79	74	69	63	57	9
82	77	71	66	60	55	49	44	10
69	63	57	52	46	41	35	30	11
55	49	44	38	33	27	22	16	12

(2) Adequate natural barriers are permitted for modifying isolation distances.

(3) Differential maturity dates are permitted for modifying isolation distances, provided there are no receptive silks in the ear parent at the same time pollen is being shed in the contaminating field.

3. Specific standards.

a. Male sterile ear parent. A male sterile ear parent can be used to produce certified hybrid corn seed by either of two methods:

(1) Seed of the normal fertile ear parent shall 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.

(2) The pollen parent shall 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.

b. Detasseling or pollen control. The following requirements apply only when 5.0% or more of the seed parent plants have receptive silks:

(1) A hybrid will be disqualified for certification if more than 1.0% of the seed parent stalks have shed pollen on any one inspection or if the total for three inspections on different dates exceeds 2.0%.

(2) Sucker tassels, portions of tassels or tassels on main plants will be counted 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 and are shedding pollen.

c. Other varieties and off-type plants:

(1) Foundation single cross and inbred lines:

(a) A field which contains at any one inspection more than 0.1% of definitely off-type or more than 2.0% of doubtful type plants that have shed or are shedding pollen when 5.0% or more of the plants in the field have receptive silks, shall not be certified.

(b) Any plant shedding pollen in male sterile rows shall be completely destroyed at pollination time to eliminate the possibility of its seed production.

D. Seed standards.

1. Single crosses and inbred lines.

a. Single crosses and inbred lines shall be graded uniformly to insure uniform planting.

b. The tolerance for other varieties or off-types is 0.1% or a total of 25 off-colored or different textured kernels per 1,000 ears.

2. Hybrid seed corn:

	Factor	Certified
	Pure Seed (minimum)	99.0%
	Total Other Crop Seeds, Including Other Varieties (maximum)	0.25%
	Total Weed Seeds (maximum)	None
	Total Inert Matter (maximum)	1.0%
	Germination (minimum)	90.0%
	Moisture (maximum)	14.0%

Historical Notes

Derived from VR172-01-01 § 9, eff. April 1980.

Statutory Authority

§§ 3.2-4024 of the Code of Virginia.