MONTANA SEED POTATO CERTIFICATION PROGRAM
Potato Lab, PO Box 172060
MSU-Bozeman * Bozeman, Montana 59717-2060 Phone: 994-3150	FAX: 994-6042
September 4, 2018

TO:	Montana Certified Seed Potato Growers FROM:	Nina Zidack, Director
RE:	Instructions for Picking Samples for BRR Test

Samples from ALL FIELDS producing Generation 2 – 5 seed potatoes must be submitted for BRR testing by PCR on tuber cores collected after harvest.

10 tubers/acre or a minimum sample size of 400 tubers/seed lot Sample core must be taken at the stolon attachment site: See back of page.
200 cores per subsamples submitted in Ziploc bags and stored at -200 C
(No Freeze /Thaw!)

Please refer to the attached sheet for an inventory of samples that you must submit. Additionally, there are examples of required sample sizes below. Please contact the Potato Lab if you have any questions.

REMEMBER: Post-harvest grow-out testing can only be as good as the sample sent. Picking representative samples is essential for accurate test results.

➢Random samples of tubers should be picked at the time of harvesting, preferably from each truck while conveying into the cellar.
Instructions for Coring Samples Coring Instructions
Count approximately 200 tuber subsamples (+/-10) from the overall sample and place into a large pail lined with a clean garbage bag. Total sample size is 10 tubers per acre or a minimum of 400 tubers/seed lot.
Disinfect coring tool by immersing in rubbing alcohol and then carefully flaming the tool with lighter or match. For safety, keep the tip of the tool pointed down until the flame goes out. Wait until the flame is completely out before starting to core.

Instructions continued on other side .....

Cores must be taken at the stolon attachment site and must be conical or semi- spherical in shape, approximately 1 cm in diameter at the top and 1 cm deep (see pictures below). Include as much of the vascular ring radiating from the stolon attachment as possible.

Place 200 cores of a subsample in a Ziploc bag (quart size) while processing the sample. Label the Ziploc bag with the farm name, generation, field number, acreage, and variety. Include any other pertinent or identifying information.
When subsample is complete, disinfect the corer as before with rubbing alcohol and flaming. Disinfect between each 200 tuber subsample. Remove the used garbage bag from the pail and line it with a clean bag for the next sample.
Original tubers must be kept in separate, labelled (so it can be linked to a lot) and sealed containers until test results are available.
Bring the samples into the lab as soon as possible. If you are unable to do so, store cored samples in the refrigerator for up to a week or place in freezer.

Examples of sample sizes:

115 acres – 1150 tuber cores total, 5 bags of 200 and one bag of 150
80 acres – 800 tuber cores total, 4 bags of 200 cores
45 acres – 450 tuber cores total, 2 bags of 200 and one bag of 50
25 acres – 400 tuber cores total, 2 bags of 200
5 acres – 400 tuber cores total, 2 bags of 200

Place each sample (all of the subsamples for one sample) in one larger bag and label with:
Farm Name
Variety and Generation Field Number
Acres

Call Potato Lab if you need a coring tool.