Biotechnology Regulatory Services

Minimum Separation Distancesto be used for

Confined Field Tests of Certain Genetically Engineered Plants

The distances used in this table are designed to be a reference point when developing designs for 

confined field tests between regulated crops and their sexually compatible non‐regulated

relatives. Separation distances are one of the measures that can be employed to meet the 

requirement in APHIS regulations that regulated articles be planted "in such a way that they are not 

inadvertently mixed with non-regulated plant materials of any species which are not part of the

environmental release (APHIS regulations 7 CFR part 340.3)." These distances are one of numerous 

measures evaluated by BRS when reviewing each application to determine if the design for the 

confined field test will prevent the dissemination and establishment of regulated GE plants. For 

example, separation distances in this table may not apply when techniques are deployed which use 

physical barriers such as bags over flowers or tents over plants to prevent cross pollination or restrict 

insect movement. In other circumstances, conditions for the confined environmental release may 

require a greater distance. BRS considers this table a "living" document and will amend the document

and make it available, as relevant scientific information becomes available. Please contact BRS to 

discuss separation distances for plants not listed in this table at biotechquery@aphis.usda.gov.

Crop iMinimum Separation Distance Notes

Alfalfa (Medicago 

sativa) 

For forage production field tests: 

10 ft from forage crops

1500 feet from seed production 

crops when leafcutter or alkali bees 

are stocked as pollinators

2640 feet from seed production 

crops when honey bees are stocked 

as pollinators

<20% flowering must be maintained in 

forage production field tests.

Distances in the presence of bees apply 

when bees are stocked anywhere within 

the indicated separation zone.

Seed production field tests: 

1500 ft from forage crops 

1 mile from seed production crops 

when leafcutter or alkali bees are 

stocked as pollinators

3 miles from seed production crops 

when honey bees are stocked as 

pollinators

Distances in the presence of bees apply 

when bees are stocked anywhere within 

the indicated separation zone.

Corn

(Zea mays)

660 ft for regulated plants that are

allowed to open pollinate

10 ft for bagged or detassled corn To prevent mechanical mixing during

agricultural operations.

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Biotechnology Regulatory Services

Crop iMinimum Separation Distance Notes

Cotton (Upland)

(Gossypium

 hirsutum)

From non-seed production cotton:

660 ft OR 40 ft of contiguous non

regulated 

iiborder rows surrounding 

the regulated cotton plus 10 ft 

minimum between fields

Nontransgenic border rows to act as a 

pollen sink for insect pollinators. 10 ft 

distance to prevent mechanical mixing 

during agricultural operations.

From seed production cotton or any 

sexually compatible wild, ruderal, or 

feral cotton: 1320 ft separation OR 

165 ft separation which includes 60 

ft nonregulated border rows or 40 ft 

of nonregulated border rows 

if iiieffective measures are taken to 

restrict cross pollination by insects. 

Rice (Oryza sativa) 360 ft (except for 1320 ft from 

hybrid rice breeding and production)

Rapeseed/Canola

(Brassica napus (L),

some B. rapa)

660 ft from other canola (B. napus) Separation from predominantly self‐

pollinating types (generally B. napus).

1320 ft from field mustard (B. rapa) Separation from predominantly

outcrossing types (generally B. rapa).

Safflower (Carthamus 

tinctorius)

1320 ft

Soybean (Glycine max 

(L))

10 ft To prevent mechanical mixing during

agricultural operations.

Tomato (Lycopersicon 

esulentum)

200 ft

Wheat (Triticum 

aestivum)

100 ft (except for 660 ft from hybrid 

wheat breeding and production)

i

Regulated trials must be separated by a minimum distance of 10 ft from any nonregulated crop to be used for 

food, feed, or seed increase (regardless of sexual compatibility) to prevent mechanical mixing. Greater distances

must be used for equipment requiring more than 10 ft for access and operation. This zone is often fallow, but 

sometimes planted with a cover crop to be plowed under. 

ii Border rows are to form a perimeter of the width specified and should be comprised of a nonregulated line of the 

same crop type flowering synchronously for the duration of flowering of the regulated crop.

iii Effective measures must be validated as effective, their implementation documented for inspection purposes, 

and any pesticides used must be applied in accordance with approved labels.

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