| (a) Test required. All Texas certified seed potatoes must be subjected to a post harvest test and meet prescribed standards to be eligible for re-certification. (b) Planting of samples. Due to the inability to detect certain virus diseases at all times under field conditions, samples from seed lots eligible for re-certification shall be planted where these diseases can be observed in the greenhouse or in the south during the winter months. (c) Selection of samples. Samples are to be selected so as to represent all field areas of any given seed lot. Tubers must be in the 2-3 ounce size range. (d) Post Harvest Test. (1) Generation 1 (stocks for sale only). Not less than 25 tubers or 1.0% of the population, not to exceed 400 tubers in a given seed lot, shall be sampled. The applicant may elect to have laboratory testing for leafroll and potato virus Y prior to vine kill conducted in lieu of a southern post harvest test at similar sampling rates. The department will determine the actual number of tubers selected. (2) Generation 2. In any given seed lot, not less than 100 tubers or 1.0% of the population, not to exceed 400 tubers or the levels established for Generations 3-6, shall be sampled (3) Generations 3-6. (A) 400 tubers per seed lot for lots up to 40 acres. (B) 800 tubers per seed lot for lots 41-80 acres. (C) An additional 200 tubers will be required for each 40 acres or portion thereof beyond 80 acres. (D) Exceptionally small lots - Not less than 100 tubers or 1.0% of the population. (e) Substitutions. Under certain circumstances a greenhouse grow-out will be substituted for the field test to meet eligibility requirements for re-certification. Sample size shall be 200 tubers of 2-3 ounce size range per seed lot. (f) Post harvest text sample. Representative post harvest test samples of suitable size will be collected by the applicant. The applicant must deliver the samples to a designated assembly point. The samples of seed tubers from all lots eligible for re-certification are grown in a post harvest test either in the greenhouse or in a southern test plot during the winter months to observe the plants for evidence of disease spread or chemical damage that may have occurred the previous growing season. Each plant in each seed lot sample is visually observed for disease symptoms. The stand count in each lot is recorded and disease content is calculated by dividing the number of diseased plants observed by the total number of tubers planted. Seed lots found to contain tuber-borne diseases in excess of prescribed tolerances will be ineligible for certification the following season. If the tubers of any seed lot sample submitted for post harvest testing do not produce plants of adequate size due to dormancy problems or the plants are destroyed due to weather, pests or other unforeseen problems at the test plot site, the respective seed lots will be evaluated by the department for re-certification eligibility on the basis of appropriate field inspection data. (g) Post Harvest Testing Disease Tolerances. In addition to the general requirements for post harvest testing, the following special requirements must be met by each generation and class of seed to be re-certified: Attached Graphic |
