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  Selecting and Buying Seed

The use of healthy seed is essential for good yields and quality. Be absolutely certain that the seed you are using is relatively free of major diseases and pests. As a general rule, use only certified seed. Certified seed is inspected by professionals and considered to meet certain strict standards. For example, certification almost invariably prohibits the known presence of bacterial ring rot, rootknot nematodes and certain other diseases which can lead to devastating crop losses. Strictly enforced tolerances have been established for other lesser pests and diseases. The Oregon Seed Certification Service provides a handy on-line listing of Oregon certified crops and the standards/tolerances required for each. Certification standards for seed potatoes are available either in printed form or on-line at Oregon  Seed Potato Certification Standards. Contact information for other Canadian and U.S. certification agencies is available at North American Seed Cert. Agencies

Certification is not a guarantee of quality. Certification reports typically emphasize what is seen during visual field inspections. Diseases present at low levels during inspection may go unobserved, increase dramatically before harvest, and lead to seed tuber infection levels far beyond tolerances. To guard against this problem, most states require some type of winter grow out test in which a small sample of each seed lot is planted and grown out for further visual inspection. Winter testing requirements vary considerably among states and among Generations within states using Limited Generation programs, as most do.

Factors other than field diseases can also affect the performance of seed. Remember, seed certification is primarily field oriented with some follow-up in winter grow out and laboratory tests. Seed handling during harvest, storage, and shipping may have more influence on crop performance than disease readings reported by certification inspectors. Seed should be carefully examined for excessive mechanical injury, decay, sprouting and shriveling before accepting delivery. Remember, when you accept delivery, the seed is yours along with all of the associated problems. If you have questions about quality, call in local experts for "third party" inspections. Keep in mind that poor seed performance may lead to lawsuits.

Seed which has been stored too warm or produced under adverse field conditions may look sound and vigorous but be physiologically "old". Old seed typically emerges, tuberizes and matures early, produces many stems and tubers, and may have lower yields than "young" seed, especially in long season locations. Physiological age of seed can be partially compensated for by changes in cultural management. On the other hand, physiological age of seed can be tailored to local needs. For example, "old" seed may be highly desirable in short season or seed production situations where early maturity or small tuber size are preferred.

A close, long-term working relationship with a few dependable seed growers is probably the best overall guarantee of consistently good seed quality year after year. By comparison, dealing with new suppliers can be dangerous. Most seed grower take care of their regular customers first and save whatever is left for new and/or late contacts (you). When dealing with new seed suppliers, on-farm visits during both the growing season and shortly before shipping are highly desirable. Also, a conscientious effort to obtain certification records and learn something about the grower's reputation is highly advisable.

Strong fences make good neighbors; so do written contracts. Make certain transaction details are clearly spelled out by using a  Seed  Sale Contract (under P.A.C.A. Regulation Sec 46.43). We apologize for the poor quality of the sample document provided here; steps are being taken to obtain an improved base copy from the original authors. It is somewhat usable (some imagination required) in its current printed form because of the pdf format.

U.S. seed certification agencies typically recommend use of some version of the North American Seed Health Certificate  which can be extremely useful in quantifying seed quality. Most good seed growers will also enthusiastically welcome the use of such forms. You will need to obtain a printed copy (using the preceding link), fill in the grower name, variety and seed lot along with your mailing address and send the form to your local state certification agency for completion. Because of the extreme importance of winter testing for viruses, be certain to obtain final certification readings which are typically available in early to mid winter. All U.S. certification agencies provide such readings but some do not reject seedlots based on winter tests. This means, of course, that "certified" seed lots can contain a much higher level of viruses than some certification standards imply at first glance.

Time invested in finding and purchasing good seed is obviously time well spent whether dealing with familiar or new trading partners. Seed prices may range from $8 - $20/cwt and growers may plant up to a ton per acre at common spacings (Table 1). The temptation to shave corners and take chances can obviously be troublesome. In such situations, bear in mind that "Good seed doesn't cost, it pays" in terms of yield, quality and profits.

         Table 1.  Approximate Cwt. of Seed Required to Plant an Acre Using 34 inch Rows¹

Seed	Seed Piece Weight, Oz.
Spacing, In.	1	1.5	1.75	2
6	19.2	28.8	33.6	38.4
8	14.4	21.6	25.2	28.8
10	11.4	17.4	20.4	22.8
12	9.6	14.4	16.8	19.2
15	7.8	11.4	13.8	15.6

             ¹For 36 inch rows, multiply by 0.93

 

A Seed Buyer’s Checklist (for a printable pdf, see A Seed Buyer’s Checklist)

• Use certified seed, preferably early generation stocks.
• Establish cordial, long-term relationships with 2-3 good seed suppliers.
• Consider planting seed lots of each variety from more than one supplier.

If R. Burbank from one supplier does poorly, for example, another lot from another
grower is available for comparison.
• Carefully check the reputation(s) of new suppliers.
• Visit prospective seed lots in the field and in storage.

When visiting farms, look for sound, healthy seed/crops and a neat, clean overall physical operation.
Quiz the grower about cultural practices, kill down dates, yields and so on. Killing vines late
to maximize seed yield is not necessarily beneficial to you.
• Be aware of unusual production problems (excess PVY, late blight, severe freezes etc.) in

production areas you are looking to for seed.
• Obtain all certification records, including results of winter grow outs.
• Develop and use a written Seed Contract specifying grade, quality, delivery & payment schedules, price, etc.

The NPC developed a “Universal Seed Contract” several years ago which is still widely used.
• Ask suppliers to provide North American Seed Health Certificates, or equivalent, for questionable lots.

These “certificates” are prepared by seed certification agencies and are, therefore, unbiased. They contain
detailed information on certification readings, history, and more. You will need to send a copy of the form along with
grower, variety and lot identification to your local seed certification office.
• Ask for a federal/state or other good "third party" shipping point inspection of each load or seed lot.

Most U.S. states require such inspections; be certain of the situation for your seed.
• Never forget that seed physical condition at planting can be critical!!

Mechanical injury and associated decay organisms (Fusarium, Erwinia, etc.), sprouting and shriveling
can be more detrimental to crop performance than all certification disease readings combined!
• Inspect seed carefully before accepting delivery.

After you accept delivery, you've not only bought the seed but also all its problems! Never sign off until
you've thoroughly checked the load for mechanical injury, decay (Fusarium dry rot, soft rots, other), shriveling,
sprouting, grade, size distribution, cleanliness and other factors affecting performance. If problems seem to be
present, notify your supplier. Depending on his response, immediately call in your local commodity inspection
service (in Oregon, contact the ODA Commodity Inspection Division – ph. 503- 986-4620) for a second inspection
and a ruling on compliance. If inspectors agree with your assessment, or even if they don’t and you remain concerned,
call in other local experts for unbiased third party opinions. Document everything!!
• If seed problems are evident and verified, provide the grower an opportunity to make amends before proceeding further.
• Maximize seed performance by storing, cutting and planting carefully.

At least half of all seed performance problems are caused by events occurring after delivery. Never store seed in
a cellar recently treated with sprout inhibitors! Don't suffocate, dry out, or overheat seed before or after cutting.
Cut, treat and plant shortly afterward in warm (>45F), moist soil when possible. Don't irrigate before emergence in normal situations!
• Maintain seed lot identity throughout the season.

Keep good records of all cutting and planting sequences and field locations for each lot.
• Sanitize cutters and other handling equipment between lots.

Cutting and planting sequence and sanitation records can be crucial in lawsuits spawned by bacterial ring rot.
• If seed disputes arise either before or after planting and emergence, call in local experts for "third party" input.

As noted above, allow your grower/supplier first opportunity to rectify the situation. Use the legal system only as a last resort.
• Think long-term, beyond the current season, when dealing with seed suppliers.
• Always strive to be a good trading partner.

Oregon Seed Production

Information on available Oregon seed stocks by variety and supplier can be found in the current Oregon Seed Growers Directory (scroll down about 13 pages). Grower addresses, phone numbers and e-mail addresses are available elsewhere in the pamphlet.

Further information about Oregon seed, including the latest  Oregon Field Readings, is available through the Oregon Seed Certification Service. Selected seed suppliers for other states and regions are linked under Seed on the PAA Website (Industry Outreach) . You may also find it useful to sell or find seed via the Potato Country Magazine seed exchange page. If you have questions about individual seed growers or seed lots for any state or Canadian province, access Seed Certification Agencies for details.

Growers --

As of 2010, Oregon relies on the labs of Lorie Ewings (University of Idaho, Moscow, ID) for certified pre-nuclear seed potatoes (see: Idaho Foundation Potato Seed Program). This material, as well as certified material from other sources is supplied to Oregon Seed Growers in various high elevation, isolated regions of the state for increase as Limited Generation stocks according to strict Certification Standards.   Oregon Seed Growers provide high quality seed of a number of chipping, fresh market and processing varieties at competitive prices. More information about Oregon seed is available from the Oregon Seed Potato Growers Association and The Oregon Seed Certification Service.

Producing Regions --

Klamath Basin--The Klamath Basin is one of several excellent high elevation, short season, isolated seed production areas. The Klamath area leads the state in total seed production. Seed is grown in several isolated valleys at an average elevation of 4,100 feet primarily in three areas: Lower Klamath Lake, Upper Klamath Lake, and Dairy-Bonanza. Klamath County has produced a large volume of seed for over 60 years. Nearly all major western varieties are grown, but Russet Burbank and Russet Norkotah dominate production. Jackson County is included in this production area.

Central Oregon--Production is centered primarily in Crook, Deschutes, and Jefferson counties with some seed in Lake County. Elevation averages 3,000 feet. Fields are located near Culver, Sisters, Redmond and Powell Butte. The area has a seed potato tradition dating back nearly 70 years. Local growers are well acquainted with the importance of high quality seed. The principal varieties are Russet Burbank, Ranger Russet, and Russet Norkotah.

Northeastern Oregon--Seed growers are located in Baker, Union, and Wallowa counties. Elevation ranges from 2,000 to 4,300 feet. Nearly all of the seed is grown at the higher elevation. Wallowa County growers have established a seed control area which prohibits production of any potatoes without an inspection for diseases. Wallowa County has produced seed for 27 years. Russet Burbank is the principal variety.

Eastern Oregon--Some seed is produced in northwest Malheur, Grant, and Harney counties, well isolated from major commercial production areas. These areas average 4,000 feet and are relatively new to seed potatoes.

Seed Production Methods

Procedures and standards for producing certified Oregon seed potatoes, including  Certification Standards, are available from  The Oregon Seed Certification Service. Similar information for other areas can be obtained from state and provincial certification agencies throughout North America (see Seed-Related Websites for WWW listings of Certification agencies and other seed related topics).
Roguing is an essential practice in the production of healthy seed potatoes in all producing regions. It is the process of identifying and disposing of abnormal plants, including tubers and seed pieces. The affected plants may be diseased, another variety, or simply different.

The following links provide useful information on seed production and storage.

Roguing Seed Potatoes (OR)
Seed Certification and Selection (ID) -- a general discussion of  certification methods and selecting healthy lots
Seed Myths? (ID)
Seed Storage, Physiology (Kimberly, Idaho) -- seed info and research
Additional Seed Related Links (PAA)

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Handling, Cutting and Sanitation

See Also

• Disinfecting Storages and Equipment (Maine)
• Seed Myths? (ID)
• Seed Certification and Selection (ID) -- a general discussion of methods
• Seed Storage, Physiology (Kimberly, Idaho) -- seed info and research
• Seed piece Size & Age, Effects of (ID)
• Selecting, Cutting and Handling Seed (U. of Me. Ext.)
• Seed Potato Selection, Handling and Planting (NDSU)
• Additional Seed Related Links

Handle seed gently at all times up to and during planting. Impacts should be minimal and changes in temperature should be gradual. Seed should be protected from drying out and overheating in truck beds by tarping and minimizing time in the field, especially in warm weather. If seed must be stored more than a few days between cutting and planting, measures should be taken to provide aeration and cooling as needed. Typically, cut seed held more than a few days should be kept at 50-55F and high humidity with good air movement (see "Storage" at this site) to promote suberizing and healing.

Seed should be warmed to about 50^oF a few days before cutting. Warm seed not only cuts better with less tissue tearing, but is also more physiologically active and heals faster than cold seed. Seed pieces should average 1.5 to 2 oz. and have a minimum of cut surface; that is, blocky seed pieces are preferred over slivers and slabs. Each seed piece should have one to several eyes depending on the variety. Some varieties may have few eyes near the tuber stem ends and produce a high percentage of "blind" (eyeless or budless) seed pieces unless special care is taken. Such varieties may call for larger seed pieces. (Ever wonder why tuber buds are called "eyes"? Because they have "eyebrows" which are actually rudimentary leaf scars.)

Before and during cutting, inspect seed for common diseases and pests such as bacterial soft rot, bacterial ring rot, Fusarium decay, powdery scab and rootknot nematodes. Excellent descriptions and control recommendations for common potato pests and diseases are available through the following sites and many others listed under Pests and Diseases:
 
• UC Davis IPM Home Page
• Online Guide to Plant Disease & Insect Management (Oregon)

• Additional Seed Related Links
• Disinfecting Storages and Equipment (Maine)
• Production Management, General
• Potatoes, General
• Seed Certification
• Seed Certification and Selection (ID) -- a general discussion of methods
• Seed Myths? (ID)
• Seed Storage, Physiology (Kimberly, Idaho) -- seed info and research
• Seed piece Size & Age, Effects of (ID)
• Selecting, Cutting and Handling Seed (U. of Me. Ext.)
• Seed Potato Selection, Handling and Planting (NDSU)