proper test conditions, errors in seedling evaluation, the presence of fungi or bacteria, or inaccuracies in counting or recording results; (d) When a sample shows seedling injury or abnormality as a result of chemical treatment, of exposure to chemicals, or of toxicity from any source. (Retest shall be made in soil or a mixture of soil and sand); (e) When no two satisfactory tests are within tolerance. EXPLANATORY NOTE: To find the maximum tolerated range, compute the average percentage of all 100-seed replicates of a given test, rounding off the result to the nearest whole number. The germination is found in the first two columns of the table. When the differences between highest and lowest replicates do not exceed the corresponding values found in the "4-replicate" column, no additional testing is required. If the differences exceed these values, omit the lowest replicate and compute the average of the three remaining replicates. If the range between the highest and lowest three replicates do not exceed the values in the "3-replicate" column for the new average percentage germination, retesting is not required and the average of the three replicates shall be regarded as the percentage germination. However, if the differences exceed the values in the "3-replicate" column, retesting is necessary. When only 200 seeds are tested, retest if the range of the two replicates exceeds the values in the "2-replicate" column. In order to form 100-seed replicates, combine subreplicates of 25 or 50 seeds which were closest together in the germinator. [25 FR 8771, Sept. 13, 1960] $201.55a Moisture and aeration of substratum. (a) The substratum must be moist enough to supply the needed moisture to the seeds at all times. Excessive moisture which will restrict aeration of the seeds should be avoided. Except as provided for those kinds of seeds requiring high moisture levels of the germination media, the substrata should never be so wet that a film of water is formed around the seeds. For most kinds of seeds blotters or other paper substrata should not be so wet that by pressing, a film of water forms around the finger. (b) The following formula may be used as a guide in the preparation of sand for germination tests: [118.3 cc. (1 GILL) SAND/ITS WEIGHT IN GRAMS]×20.2-8.0=THE NUMBER OF CC. OF WATER TO ADD TO EACH 100 GRAMS OF AIR-DRY SAND. (c) The amount of water provided by this formula is satisfactory for seeds the size of clovers and will have to be modified slightly, depending on the kind of seed being tested and the kind of sand used. For example, slightly more moisture should be added when the larger seeds are to be tested. (d) In preparing soil tests water should be added to the soil until it can be formed into a ball when squeezed in the palm of the hand but will break freely when pressed between two fingers. After the soil has been moistened it should be rubbed through a sieve and put in the seed containers without packing. (e) The addition of water subsequent to placing the seed in test will depend on the evaporation from the substrata in the germination chambers. Since the rate of evaporation will depend upon the relative humidity of the air, it is desirable to keep water in the germination chambers or to provide other means of supplying a relative humidity of approximately 95 percent. Germination tests should be observed at frequent intervals to insure an adequate moisture supply of the substrata at all times. [20 FR 7931, Oct. 21, 1955] §201.56 Interpretation. (a) A seed shall be considered to have germinated when it has developed those essential structures which, for the kind of seed under consideration, are indicative of its ability to produce a normal plant under favorable conditions. In general, the following are considered to be essential structures necessary for the continued development of the seedling (although some structures may not be visible in all kinds at the time of seedling evaluation). Seedlings possessing these essential structures are referred to as normal seedlings: Root system (consisting of primary, secondary, seminal, or adventitious roots); hypocotyl; epicotyl; cotyledon(s); terminal bud; primary leaves; and coleoptile and mesocotyl (in the grass family). Abnormal seed lings consist of those with defects to these structures, as described in the abnormal seedling descriptions, and are judged to be incapable of continued growth. The seedling descriptions assume that test conditions were adequate to allow proper assessment of the essential seedling structures. (b) Sand and/or soil tests may be used as a guide in determining the classification of questionable seedlings and the evaluation of germination tests made on approved artificial media. This is intended to provide a method of checking the reliability of tests made on artificial substrata when there may be doubt as to the proper evaluation of such tests. (c) Seedlings infected with fungi or bacteria should be regarded as normal if all essential structures are present. A seedling that has been seriously damaged by bacteria or fungi from any source other than the specific seed should be regarded as normal if it is determined that all essential structures were present before the injury or damage occurred. Germination counts should be made on samples where contamination and decay are present at approximately 2-day intervals between the usual first count and the final count. During the progress of the germination test, seeds which are obviously dead and moldy and which may be a source of contamination healthy seeds should be removed at each count and the number of such dead seeds should be recorded. When symptoms of certain diseases develop which can be readily recognized and identified, their presence should be noted. of (d) Seed units containing more than one seed or embryo, such as New Zealand spinach seed, Beta seed, double fruits of the carrot family (Umbelliferae), multiple seeds of burnet, and seed units of grasses consisting of multiple florets, shall be tested as a single seed and shall be regarded as having germinated if they produce one or more normal seedlings. (e) Standard guides for seedling interpretation shall include the following descriptions for specific kinds and groups. The "General Description" for each group of crop kinds describes a seedling without defects. While such a seedling is clearly normal, seedlings with some defects may also be classified as normal, provided the defects do not impair the functioning of the structure. The "Abnormal seedling description" is to be followed when judging the severity of defects. [20 FR 7931, Oct. 21, 1955, as amended at 25 FR 8771, Sept. 13, 1960; 59 FR 64500, Dec. 14, 1994] $201.56-1 Goosefoot family, Chenopodiaceae, and Carpetweed family, Aizoaceae. Kinds of seed: Beet, Swiss chard, fourwing saltbush, spinach, New Zealand spinach, and forage kochia. (a) General description. (1) Germination habit: Epigeal dicot. (2) Food reserves: Leaf-like cotyledons and perisperm. (3) Shoot system: The hypocotyl elongates carrying the cotyledons above the soil surface. The epicotyl usually does not show any development within the test period. (4) Root system: A primary root; secondary roots may develop within the test period. (5) Seedling: Frequent counts should be made on multigerm beet since the growing seedlings will separate from the cluster making it difficult to identify the source. Any cluster which produces at least one normal seedling is classified as normal; only one normal seedling per cluster is to be counted (see §201.56(d)). Toxic substances from the clusters of beet and Swiss chard may cause discoloring of the hypocotyl and/or root. Seedlings which are slightly discolored are to be classified as normal; however, if there is excessive discoloration, retest by the method in §201.58(b)(3). (b) Abnormal seedling description. (1) Cotyledons: (i) Less than half of the original cotyledon tissue remaining attached. (ii) Less than half of the original cotyledon tissue free of necrosis or decay. (2) Epicotyl: (i) Missing. (May be assumed to be present if cotyledons are intact.) (ii) [Reserved] (3) Hypocotyl: (i) Deep open cracks extending into the conducting tissue. (ii) Malformed, such as markedly shortened, curled, or thickened. (iii) Shoot system: The hypocotyl elongates and carries the cotyledons above the soil surface. The epicotyl usually does not show any development within the test period. (iv) Root system: A long primary root. (v) Seedling: The interpretations of lettuce seedlings are made only at the end of the test period. (2) Abnormal seedling description. (i) Cotyledons: (A) Less than half of the original cotyledon tissue remaining attached. (B) Less than half of the original cotyledon tissue free of necrosis or decay. (Remove attached seed coat for evaluation of cotyledons. Physiological necrosis is manifested by discolored areas on the cotyledons and should not be confused with natural pigmentation of some lettuce varieties.) (ii) Epicotyl: (A) Missing. (May be assumed to be present if cotyledons are intact.) (B) Any degree of necrosis or decay. (iii) Hypocotyl: (b) Other kinds in the sunflower family: Artichoke, cardoon, chicory, dandelion, endive, great burdock, safflower, salsify, Louisiana sagewort, and sunflower. (1) General description. (i) Germination habit: Epigeal dicot. (ii) Food reserves: Cotyledons which expand and become thin, leaf-like, and photosynthetic. (iii) Shoot system: The hypocotyl elongates and carries the cotyledons above the soil surface. The epicotyl usually does not show any development within the test period. (iv) Root system: A long primary root with secondary roots usually developing within the test period. (2) Abnormal seedling description. (i) Cotyledons: (A) Less than half of the original cotyledon tissue remaining attached. (B) Less than half of the original cotyledon tissue free of necrosis or decay. (Remove any attached seed coats at the end of the test period for evaluation of cotyledons.) (ii) Epicotyl: (A) Missing. (May be assumed to be present if cotyledons are intact.) (B) [Reserved] (iii) Hypocotyl: (A) Deep open cracks extending into the conducting tissue. (B) Malformed, such as markedly shortened, curled, or thickened. (C) Watery. Kinds of seed: Broccoli, brussels sprouts, cabbage, Chinese cabbage, cauliflower, collards, garden cress, upland cress, water cress, kale, Chinese kale, Siberian kale, kohlrabi, mustard, pakchoi, radish, rape, rutabaga, and turnip. (a) General description. (1) Germination habit: Epigeal dicot. (2) Food reserves: Cotyledons which expand and become thin, leaf-like and photosynthetic. In Brassica, Sinapis, and Raphanus, the cotyledons are bilobed and folded, with the outer cotyledon being larger than the inner. (3) Shoot system: The hypocotyl elongates and carries the cotyledons above the soil surface; the epicotyl usually does not show any development within the test period. (4) Root system: A long primary root. (b) Abnormal seedling description. (1) Cotyledons: (i) Decayed at point of attachment. (ii) Less than half of the original cotyledon tissue remaining attached. (iii) Less than half of the original cotyledon tissue free of necrosis or decay. (2) Epicotyl: (i) Missing. (May be assumed to be present if the cotyledons are intact.) (ii) [Reserved] (3) Hypocotyl: (i) Deep open cracks extending into the conducting tissue. (ii) Malformed, such as markedly shortened, curled, or thickened. (iii) Watery. (4) Root: West India gherkin, melon, pumpkin, squash, and watermelon. (a) General description. (1) Germination habit: Epigeal dicot. (2) Food reserves: Cotyledons which are large and fleshy; they expand, become photosynthetic, and usually persist beyond the seedling stage. (3) Shoot system: The hypocotyl elongates and the cotyledons are pulled free of the seed coat, which often adheres to a peg-like appendage at the base of the hypocotyl. The epicotyl usually does not show any development within the test period. (4) Root system: A long primary root with numerous secondary roots. (b) Abnormal seedling description. (1) Cotyledons: (i) Less than half of the original cotyledon tissue remaining attached. (ii) Less than half of the original cotyledon tissue free of necrosis or decay. (Remove any attached seed coats at the end of the test period for evaluation of cotyledons.) (2) Epicotyl: (i) Missing. (May be assumed to be present if the cotyledons are intact.) (ii) [Reserved] (3) Hypocotyl: (i) Deep open cracks extending into the conducting tissue. (ii) Malformed, such as markedly shortened, curled, or thickened. (4) Root: (i) None. (ii) Weak, stubby, or missing primary root, with less than two strong secondary or adventitious roots. (5) Seedling: (i) One or more essential structures impaired as a result of decay from primary infection. (ii) Food reserves: Endosperm. The scutellum is a modified cotyledon which is in direct contact with the endosperm. During germination the scutellum remains inside the seed to absorb nutrients from the endosperm and transfer them to the growing seedling. (iii) Shoot system: The shoot consists of the coleoptile, leaves enclosed in the coleoptile, and the mesocotyl. The coleoptile elongates and pushes through the soil surface; the mesocotyl may elongate depending on the variety and light intensity, but may not be discernible. Splitting of the coleoptile occurs naturally as a result of growth and emergence of the leaves. (iv) Root system: A primary root and seminal roots. The primary root is not readily distinguishable from the seminal roots; therefore, all roots arising from the seed are referred to as seminal roots. (2) Abnormal seedling description. (C) Leaf extending less than halfway up into the coleoptile. (D) Leaf extensively shredded or split. (E) Spindly or watery. (F) Grainy, spirally twisted, shredded, and weak. (G) Deep open cracks in the mesocotyl. (ii) Root: (A) Less than one strong seminal root. (B) [Reserved] (iii) Seedling: |