Fairly strict certification requirements have been developed to ensure continued genetic purity of high quality seed, from breeders' seed to that ultimately purchased by the consumer.
Land must not have grown or been seeded to any tall fescue during the previous 5 yr to be eligible to produce Foundation seed. Land must not have grown or been seeded to these grasses during the previous 18 mo to produce Registered or Certified seed, unless the previous crop was of the same cultivar and class, and certified. Tall fescue must be planted in distinct rows. Our experience suggests that more than the minimum 2 yr paddock history is required to avoid ryegrass contamination and meet the New Zealand Seed Certification Standards.
Isolation is the minimum distance required between any two tall fescue cultivars by a Seed Certification Scheme to ensure that a high level of genetic purity is maintained. An example of minimum isolation distances between crops of different classes and paddock size is shown in Table 23-1.
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Table 23-1. New Zealand field inspection standards for the presence of "off types" and isolation requirements.
Seed Certification rules set standards for the number of "off-types" or contaminants that will be accepted during preharvest field inspections of crops (Table 23-1).
The Seed Certification rules also set purity standards. These standards vary among classes of seed produced (Registered/Basic versus First Generation Seed) and among countries both for minimum purity and maximum weed content or other seed content allowed. Tall fescue First Generation purity standards range from 98% in New Zealand to 95% in Canada and Chile, while the maximum level of other seeds (crop and/or weeds) ranges from 1.0 to 5.0%. Ryegrass contamination is a major problem for seed producers and sometimes for end users, whereas contamination in turf tall fescues by orchardgrass (Dactylis glomerata L.) is a serious problem for end users.
There also are rules on the presence of noxious (prohibited) weeds in both field and seedlot. The rules vary among countries, but species that commonly are included in this category are nodding thistle (Cardus nutans L.) and wild oat (Avena fatua L.), while dock (Rumex spp.) is an unacceptable contaminant in seedlots exported to Australia and many other countries.
Standards developed by the Oregon Seed Certification Service (OSCS) for tall fescue seed production in Oregon can be found in the OSCS Handbook (http://seedcert.oregonstate.edu; verified 10 Jan. 2010). These standards and the following specific regulations together constitute the Certified Tall Fescue Standards (Tables 23-2 and 23-3). About two-thirds of the Oregon tall fescue seed production area is entered into the OSCS program each year.
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Table 23-3. Seed standards in Oregon-minimum sample size: 0.23 kg (0.5 lb).
Our observations suggest that the best sites for seed production are on deep, fertile soils with high water-holding capacity. On sandier soils, irrigation or reliable summer rainfall is important for obtaining good seed yields (see General Management, Irrigation section of this chapter). Sites that frequently experience out of season frosts during late spring are not suitable for early flowering cultivars (see General Management, Frosts section of this chapter).
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