(a) Identification requirements. Each lot of seed potatoes entered for certification shall be identified as Limited Generation, Non-Generation Certified or Experimental. Experimental seed must be accompanied by written authorization from the breeding program from which the numbered potato selections originate (germplasm release notice). Each seed lot must meet all General Requirements and applicable Special Requirements provided herein. Any seed lot brought into the Texas limited generation system from out-of-state will have its entry level determined by the State Seed and Plant Board. Listed below are the various steps that any given seed stock will pass through in the Limited Generation System:
  (1) Nuclear (Lab and/or greenhouse produced)
  (2) Generation 1 (1st year in field)
  (3) Generation 2 (2nd year in field)
  (4) Generation 3 (3rd year in field)
  (5) Generation 4 (4th year in field)
  (6) Generation 5 (5th year in field)
  (7) Generation 6 (6th year in field)
(b) Seed sources and disease tolerance standards.
  (1) Nuclear.
    (A) Seed source. Seed must be from single hill field selections obtained from certified seed of Generation 5 or earlier generations or from a source approved by the department.
    (B) Disease symptoms. A seed must be free of all visible disease symptoms. Testing for Clavibacter michiganensis subsp.sepedonicus will be handled as outlined in the "Protocol for Indexing and Confirmation of Diagnosis of Bacterial Ring Rot of Potato" (accepted 12/1/99 by the NPC U.S. Seed Potato Certification Subcommittee).
    (C) Mother plants. Those units (plantlets) initiated from field selected plants or tubers. All mother plants to be used for subsequent propagation must be tested and proven negative for the following disease organisms: Clavibacter michiganensis subsp. sepedonicus, Erwinia carotovora subsp. atroseptica and carotovora, potato viruses X, S, Y, A and M (hereafter referred to as PVX, PVS, PVY, PVA and PVM), PVM-ID, Potato Latent virus, potato leafroll virus (PLRV), and potato spindle tuber viroid (PSTV).
    (D) Nuclear stocks. Those stocks derived from mother plants. These include material used in maintaining a clone bank, plantlets increased for use in production of in-vitro microtubers, microtubers, plantlets increased for use in field production of tubers, and minitubers produced in a greenhouse.
    (E) Clone bank. The clone bank in-vitro stocks will be tested on an annual basis and found negative for PVX, PVS, PVY, PVM, Clavibacter michiganensis subsp. sepedonicus, and Erwinia carotovora subspp. atroseptica and carotovora.
    (F) Plantlet/greenhouse production. Representative samples of micropropagated materials for use in field or greenhouse plantings, of not less than 10 units and not to exceed 1.0% of the planting stock, must be tested for PVX and PVS to verify that such material still tests negative for these pathogens. In the case of greenhouse production, the testing will take place between the time of first and second visual inspections. In the event that trace amounts of virus are detected, the applicant will be informed of the results and have the seed lot in question classified accordingly upon completion of the Generation 1 field-testing. Greenhouse stocks will have an additional test for the presence of Erwinia carotovora subspp. and Clavibacter michiganensis subsp. sepedonicus (Cms) completed at the same rate as above on the minitubers. A positive test for presence of Erwinia carotovora subspp. shall result in downgrading of the stocks to Generation 2 for sale outside the originating applicant's program. However, the contaminated stocks may be replanted for certification and entered as Generation 1 on the original applicant's farm. Under certain circumstances an additional test for Phytophthora infestans will be performed on the minitubers brought in for testing. A positive result for either P. infestans or Cms will result in rejection of the lot(s) from certification.
  (2) Generation 1.
    (A) Seed source must be Nuclear stocks approved by the State Seed and Plant Board. All Nuclear seed stocks must have a Certificate of Origin, label, or similar document available for inspection by the department prior to being accepted into the certification program.
    (B) Tubers must be planted in identifiable family units.
    (C) Each family unit will be lab tested for PVX and PVS and, at the applicant's option for potato leafroll virus. At least 1.0% of the plants, not to exceed 1000 plants, must be sampled. If there are indications that viral infection has taken place, then, at the applicant's option, at least one leaflet from each plant in the infected family unit will be sampled to identify and aid in removal of the infected plants, or blocks of samples will be tested to determine the extent of the infection. If the applicant refuses additional testing or the level of virus found in the stocks is too high for removal of infected plants, the lot will be downgraded to the next appropriate generation level. Trace PVX or PVS infections, as determined by the department, will not result in downgrading of the lot if replanted for certification on the original applicant's farm the following year.
    (D) Must meet Class A requirements or will be downgraded to next appropriate generation level.
  (3) Generation 2.
    (A) Seed source must be Nuclear or Generation 1 and family units may be maintained.
    (B) Representative samples of at least 200 leaflets per acre will be tested for PVX and, at the applicant's option, tested for PVS.
    (C) Must meet Class A or B requirements or will be downgraded to Generation 3.
  (4) Generation 3.
    (A) Seed source must be Generation 2 or earlier generations.
    (B) Representative samples of at least 20 leaflets per acre and not less than 100 leaflets from any given seed lot will be tested for PVX and, at the applicant's option, tested for PVS.
  (5) Generation 4. Seed source must be Generation 3 or earlier generations.
  (6) Generation 5. Seed source must be Generation 4 or earlier generations.
  (7) Generation 6.
    (A) Seed source must be Generation 5 or earlier generations.
    (B) May be labeled and sold as Generation 6 but is not eligible for certification the following year.
(c) Isolation for Limited Generation Seed. Field Isolation.
  (1) Generations 1-3 potatoes must be separated from Generations 4-6, Non-Generation Certified and Experimental lots by a minimum distance of at least two blank row widths.
  (2) Storage Isolation.
    (A) Generation 1 potatoes must be isolated from all other certified potatoes in the same storage building. Emphasis should be directed toward intensive sanitation and physical separation by solid wall partitions.
    (B) All certified seed lots must be kept in a storage bin that contains only seed entered for certification. Non-certified stocks and potatoes rejected due to blackleg or zero tolerance diseases such as bacterial ring rot will not be allowed in the storage bin; the presence of such potatoes will result in rejection of the certified seed lots present.
(d) Field Inspection Tolerances for Limited Generation Seed.
Attached Graphic
(e) Sale of Nuclear Material from Private or Applicant Operated Laboratories.
  (1) Rules governing the seed sources and disease tolerance standards for Nuclear stocks must be followed. All stocks not initiated in the year of production or sale must have an annual testing for the presence of disease organisms and a grow-out or other test approved by the department to verify trueness to type and varietal identification.
  (2) Accurate and complete accession records must be kept on all nuclear stocks and be available for review if requested by the department. Information should include year of initiation into tissue culture, source of the line, general increase data, pertinent field performance characteristics, and disease testing history.
  (3) All greenhouse-produced stocks (minitubers) shall have at least two inspections during their growth. At the time of the second inspection, prior to vine death, plants will be examined to verify trueness to type and varietal identification. Minitubers will be examined in storage for any apparent problems prior to shipment or subsequent field growth.
  (4) All nuclear stocks must be kept in a clone bank with accurate identification on each tube or vessel. These stocks shall be kept in the clone bank no less than one year from the date of any sale.
  (5) Nuclear stocks sold will not be labeled with an official label or bulk certificate used on other certified seed stocks. Instead, there will be an affidavit included with the nuclear material which carries information relating to its accession, disease testing records, varietal identification, numbers sold, and product identity (i.e., minitubers, tissue culture plantlets, microtubers, etc.). The stocks will be recorded as eligible for certification as Generation 1 under these rules and regulations.

Source Note: The provisions of this §10.48 adopted to be effective November 7, 2006, 31 TexReg 8983