Official North Dakota seed potato grades

Final grade determination shall be made based on physical defects, size, shape, and cleanliness. The potatoes will be packed in new sacks, totes, or clean, disinfected containers identified by labels as to variety, crop year, and grower and accompanied by an official state or federal grade certificate. United States department of agriculture revised standards, effective March 2012, for seed potatoes shall be the official guide for applying and interpreting all definitions and terms used in North Dakota seed potato grades. Grade inspection will be made on a sample basis. 1. First grade blue tag seed potatoes shall consist of unwashed potatoes of one variety which must meet the following requirements: a. Shape. Fairly well-shaped except for long varieties. (1) Dryland type (see definitions section 74-04-01-01). (2) Except for shape (see definitions section 74-04-01-01). b. Free from: (1) Freezing injury. (2) Blackheart. (3) Soft rot and wet breakdown. (4) Late blight tuber rot. (5) Bacterial ring rot. (6) Nematode or tuber moth injury. (7) Fresh cuts or fresh broken-off second growth. c. Free from serious damage caused by: (1) Hollow heart. (2) Vascular ring discoloration. (3) Wireworm. (4) Growth cracks. d. Free from damage by soil and other causes (see definitions section 74-04-01-01 and classification of defects, section 6, tables I and II of section 74-04-01-11). e. Size: (1) Minimum size, unless otherwise specified, must be one and one-half inches [38.1 millimeters] in diameter. (2) Maximum size may not exceed twelve ounces [340.2 grams] for round-shaped or intermediate-shaped varieties and fourteen ounces [396.9 grams] for long varieties. (3) For all varieties, size B must be from one and one-half inches [38.1 millimeters] to not more than two and one-quarter inches [57.1 millimeters] in diameter. f. Tolerances. In order to allow for variations incident to proper grading and handling in the foregoing grade, the following tolerances, by weight, are provided as specified: (1) For defects: (a) Ten percent for potatoes in any lot which are seriously damaged by hollow heart. (b) Ten percent for potatoes in any lot which are damaged by soil. (see definitions section 74-04-01-01). (c) Five percent for potatoes in any lot which are seriously damaged by vascular ring discoloration. (d) Potatoes affected by silver scurf are not grade factors. (e) Not more than ten percent of the potatoes seriously damaged by wireworm. (f) Eleven percent for potatoes which fail to meet the remaining requirements of grade, including therein not more than six percent for external defects and not more than five percent for internal defects; provided that included in these tolerances not more than the following percentages shall be allowed for the defects listed: Percent Bacterial ring rot 0.00 Late blight tuber rot 1.00 Damage by dry-type or moist-type fusarium tuber rot 2.00 Nematode or tuber moth injury 0.00 Frozen, soft rot, or wet breakdown 0.50 Varietal mixture 0.50 (2) For off-size: (a) Undersize. Five percent for potatoes in any lot which fail to meet the required or specified minimum size. (b) Oversize. Ten percent for potatoes in any lot which fail to meet the required or specified maximum size. 2. Second grade yellow tag potatoes shall consist of unwashed potatoes that meet the requirements for blue tag grade except for defects caused by hollow heart, wireworm, internal discoloration, firmness, sprouts, and sunken, flattened, or depressed areas with or without underlying flesh discolored, and are not seriously damaged by soil and for increase in maximum size, and for increased tolerance for defects listed below: Tolerances. a. For defects: (1) Twenty percent for potatoes seriously damaged by hollow heart. (2) Firmness, sprouts, wireworm, internal discoloration, sunken, flattened, or depressed areas with or without underlying flesh discolored and growth cracks are not grade factors. (3) Twenty percent for potatoes which fail to meet the remaining requirements of the grade; provided, that included in this amount not more than six percent shall be seriously damaged and included therein not more than one-half of one percent shall be allowed for potatoes which are frozen or affected by soft rot or wet breakdown. b. Size. Maximum size, unless otherwise specified may not exceed fourteen ounces [396.90 grams] for round-shaped or intermediate-shaped varieties and sixteen ounces [453.60 grams] for long varieties. 3. White tag. The white tag North Dakota-certified seed potato grade shall consist of certified seed potatoes of one variety that are graded according to agreement between the seller and the purchaser as to size and defects, except that not more than one-half percent of soft rot, fozen, or wet breakdown and two percent dry rot, of which not more than one percent late blight tuber rot is allowed. Import requirements may be considered an agreement. The official label must be used and marked as white tag. 4. The blue tag, yellow tag, or white tag grade designation may not be used on the official label unless the seed has been grade inspected. Noninspected seed must be labeled "no grade". 5. Application of tolerances. Individual samples may not have more than double the tolerances specified, except that at least one defective and one off-size potato may be permitted in any sample; provided that en route or at destination, one-tenth of the samples may contain three times the tolerance permitted for potatoes which are frozen or affected by soft rot or wet breakdown; and provided, further, that the averages for the entire lot are within the tolerances specified for the grade. 6. Samples for grade and size determination. Individual samples shall consist of at least twenty pounds [9.06 kilograms]. The number of such individual samples drawn for grade and size determination will vary with the size of the lot. 7. Classification of defects. a. Brown discoloration following skinning, dried stems, flattened depressed areas (showing no underlying flesh discoloration), greening, skin checks, and sunburn do not affect seed quality and may not be scored against the grade. b. Table I - External defects. DAMAGE Defect When materially OR When removal causes a loss of detracting from the appearance of the potato more than 5 percent of the total weight of the potato Air cracks x Bruises x Cuts and broken-off second growth (healed) x x Elephant hide (scaling) x Enlarged, discolored, or sunken lenticels x Folded ends x Second growth x Shriveling When more than moderately shriveled, spongy, or flabby. Sprouts When more than 20 percent of the potatoes in any lot have any sprout more than 1 inch [25.4 millimeters] in length. Surface cracking x x Flea beetle injury x x Grub damage x x Rodent and/or bird damage x x Wireworm or grass damage Any hole more than 3/4 inch [19.1 millimeters] long or when the aggregate length of all holes is more than 1 1/4 inches [31.8 millimeters]1. Dry-type or moist-type fusarium rot x Rhizoctonia x Scab, pitted x x Scab, russet When affecting more than 1/3 of the surface. Scab, all surface When affecting more than 5 percent of the surface. Growth cracks When seriously detracting from the appearance. Pressure bruises and sunken When removal causes a loss of areas with underlying flesh discolored more than 10 percent of the total weight. 1Definitions of damage and serious damage are based on potatoes that are two and one-half inches [63.5 millimeters] in diameter or six ounces [170.10 grams] in weight. Correspondingly lesser or greater areas are permitted on smaller or larger potatoes. c. Table II - Internal defects. DAMAGE Defect When materially detracting from the appearance of the potato OR When removal causes a loss of more than 5 percent of the total weight of the potato Ingrown sprouts x Internal discoloration occurring interior to the vascular ring (such as, internal brown spot, mahogany browning, and heat necrosis). When more than the equivalent of three scattered light brown spots 1/8 inch [3.2 millimeters] in diameter1. All other internal discoloration, excluding dis- coloration confined to the vascular ring. x SERIOUS DAMAGE Defect When seriously detracting from the appearance of the potato OR When removal causes a loss of more than 10 percent of the total weight of the potato Internal discoloration confined to the vascular ring. x Hollow heart or hollow heart with discoloration. When affected area exceeds that of a circle 3/4 inch [19.1 millimeters] in diameter1. 1Definitions of damage and serious damage are based on potatoes that are two and one-half inches [63.5 millimeters] in diameter or six ounces [170.10 grams] in weight. Correspondingly lesser or greater areas are permitted on smaller or larger potatoes. 8. Classification and serologically tested stocks. a. Foundation seed classification may be indicated on the lab provided the lot meets foundation standards. b. Serologically tested stocks for potato virus x, potato virus s, potato virus y, potato virus a, or potato virus m may be so indicated on the label if within the specified tolerance during the current growing season. 9. Grade inspections are not intended to induce growers' or producers' reliance regarding the presence or absence of disease, the identity of the variety or selection, quantity, or quality of the seed or crop produced or the fitness of the seed. Blue tag, yellow tag, and white tag shipments must be inspected and meet respective grade requirements.