MAIZE (Zea mays L.) HYBRIDS
I. Application and Amplification of General Seed Certification Standards
A. The General Seed Certification Standards are basic and together with the following specific standards constitute the standards for certification of hybrid maize seed.
B. The general standards are amplified as follows to apply specifically to the hybrids of maize.
1. Eligibility requirements for certification
(a) A hybrid is one to be planted for any use except seed production. It may be one of the following.
(i) Single cross - the first generation resulting from the controlled crossing of two approved inbred lines.
(ii) Double cross - the first generation resulting from the controlled crossing of two certified single crosses.
(iii) Three way cross - the first generation resulting from the controlled crossing of an approved inbred line and a certified single cross.
(iv) Top cross - the first generation resulting from the controlled crossing of an approved inbred line and a certified open pollinated variety.
(v) Double top cross - the first generation resulting from the controlled crossing of a certified single cross and a certified open pollinated variety.
2. Classes and sources of certified seed
(a) Only the class "certified" shall be recognised.
(b) A hybrid to be certified must be produced from certified foundation seed or seeds stocks approved by the Certification Agency.
3. Seed house or bin inspection
The foundation single cross shall be ear-inspected after maturity by the Certification agency.
II. Land requirements
Land to be used for seed production of hybrid maize shall be free of volunteer plants.
III. Field Inspection
A minimum of four inspections shall be made in such a way that one is done before flowering and the remaining three during flowering.
IV. Field Standards
A. General requirements
1. Isolation
(a) A specific hybrid of maize shall be isolated from the contaminants shown in the column 1 of the Table below by the distances specified in column 2 of the said Table:
Contaminants Minimum distance (meters)
1 2
* Fields of any maize with same kernel
colour and texture 200
Fields of any maize with different kernel
colour and texture and teosinte 300
* Fields of same hybrid (code designation) not
conforming to varietal purity requirements for certification 200
* Fields of other hybrids having common male parent
and conforming to varietal purity requirements for certification 5
* Fields of other hybrids having common male parent and
not conforming to varietal purity requirements for certification 200
* Distances less than 200 meters may be modified by planting border rows of male parent, if the kernel colour and texture of the contaminant are the same as that of the seed parent. The number of border rows to be planted all around the seed field to modify isolation distances less than 200 meters shall be determined by the size of the field and its distance from the contaminant as shown in the table below:
When the field area (in hectares) growing the concerned seed parent is Then the minimum number of
border rows required is:
More than: 4 6 8 10 12 14 16
Upto:4 6 8 10 12 14 16 or over
and the distance (in meters) of the seed parent from other maize with
kernel colour and texture the same as that of the seed parent is at least:
200.0 195.0 190.0 185.0 180.0 175.0 170.0 165.0 1
187.5 182.5 177.5 172.5 167.5 162.5 157.5 152.5 2
175.0 170.0 165.0 160.0 155.0 150.0 145.0 140.0 3
162.5 157.5 152.5 147.5 142.5 137.5 132.5 127.5 4
150.0 145.0 140.0 135.0 130.0 125.0 120.0 115.0 5
137.5 132.5 127.5 122.5 117.5 112.5 107.5 102.5 6
125.0 120.0 115.0 110.0 105.0 100.0 95.0 90.0 7
112.5 107.5 102.5 97.5 92.5 87.5 82.5 77.5 8
100.0 95.0 90.0 85.0 80.0 75.0 70.0 65.0 9
87.5 82.5 77.5 72.5 67.5 62.5 57.5 52.5 10
75.0 70.0 65.0 60.0 55.0 50.0 45.0 40.0 11
62.5 57.5 52.5 47.5 42.5 37.5 32.5 27.5 12
50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 13
This table applies to all sides of the seed field exposed to contamination, whether located directly opposite or diagonally.
(b) Border rows must be planted in the seed field or adjacent to it, but in no case separated by more than five meters from the seed field.
(c) Border rows must be planted at the same time as the rest of the seed field so that the flowering time of both is the same: i.e., border rows should be shedding pollen when silks in the seed parent is receptive.
(d) Border rows must be planted all along and opposite to to the contaminating maize.
(e) There should be a reasonable stand of border rows; i.e., there must not be gaps in the border rows. Border rows must have been planted using the seed rate and spacing adopted for the seed crop.
(f) The area planted under border rows is taken in to consideration while modifying the isolation distance.
(g) Seed fields having diagonal exposure to contaminating fields are to be planted with border rows in both directions of exposure.
(h) If two hybrid seed fields with different pollinator parents are with in the isolation distance of one another, border rows are necessary for each of them in order to avoid contamination of the respective seed parent.
(i) Natural barriers such as tall thick trees, buildings etc. between the seed and contaminating fields shall not be a substitute to border rows.
(j) Border rows must be planted with the seed used for planting male rows in the seed field. Seed saved from male rows of the previous production of the same cross cannot be used for planting of border rows or for planting within the isolation distance.
(k) The isolation distance continues to be 300 meters if the kernel colour or texture of the contaminating maize is different from that of the seed parent or if the contaminating field is planted with sweet corn, popcorn or teosinte. In this case modification of isolation distance by planting border rows will not be permitted.
(l) Differential blooming dates are permitted for modifying isolation distances, provided 5.0 % or more of the seed parent plants do not have receptive silks when more than 0.50 % of plants in the field(s) within the isolation distance are shedding pollen.
B. Specific requirements
Factor Maximum permitted (%)*
Offtype plants that have shed or shedding
pollen in male parent at any one inspection during
flowering when 5.0 % or more of the plants in the
seed field have apparently receptive silks 0.50
Tassels of the plant that have shed or shedding pollen in the
seed parent at any one inspection during flowering when 5.0 %
or more of the plants in the seed field have apparently receptive silks 1.00
Total of pollen shedding tassels including tassels that have shed pollens
for all three inspections conducted during flowering on different dates 2.00
Offtype plants in seed parent at final inspection 0.50
* Sucker tassels, portions of tassels, and tassels on main plants shall be counted as shedding pollen only when two inches or more of the centre spike, the side branches, or a combination of the two have the anthers exserted from the glumes and are shedding pollen.
V. Seed standards
A. Seed ears inspected after harvest shall not contain in excess of 0.20 % offtype ears including ears with off-coloured kernels.
Factor Standard
Pure seed (minimum) 98.0%
Inert matter (maximum) 2.0%
Other crop seeds (maximum) 10/kg
Other distinguishable varieties based on
kernel colour and texture (maximum) 10/kg
Weed seeds (maximum) None
Germination (minimum) 90%
Moisture (maximum) 12.0%
For vapour-proof containers (maximum) 8.0%
B. Shelling
Shelling of the seed ears will be made only after obtaining approval from the Certification agency.