Reliability of different methods used for forming of working samples in the laboratory for seed testing

The testing of seed quality starts from the moment a sample is formed in a warehouse during processing or packaging of the seed. The seed sampling as the process of obtaining the working sample also assumes each step undertaken during its testing in the laboratory. With the aim of appropriate forming of a seed sample in the laboratory, the usage of seed divider is prescribed for large seeded species (such as seed the size of wheat or larger) (ISTA Rules, 1999). The aim of this paper was the comparison of different methods used for obtaining the working samples of maize and wheat seeds using conical, soil and centrifugal dividers. The number of seed of added admixtures confirmed the reliability of working samples formation. To each maize sample (1000 g) 10 seeds of the following admixtures were added: Zea mays L. (red pericarp), Hordeum vulgäre L., Triticum aestivum L., and Glycine max (L.) Merr. Two methods were used for formation of maze seed working sample. To wheat samples (1000 g) 10 seeds of each of the following species were added: Avena saliva (hulled seeds), Hordeum vulgäre L., Galium tricorne Stokes, and Polygonum lapatifolmm L. For formation of wheat seed working samples four methods were used. Optimum of 9, but not less than 7 seeds of admixture were due to be determined in the maize seed working sample, while for wheat, at least one seed of admixture was expected to be found in the working sample. The obtained results confirmed that the formation of the maize seed working samples was the most reliable when centrifugal divider, the first method was used (average of admixture - 9.37). From the observed admixtures the seed of Triticum aestivum L. was the most uniformly distributed, the first method also being used (6.93). The second method gains high average values satisfying the given criterion, but it should be used with previous homogenization of the sample being tested. The forming of wheat seed working samples is the most reliable if the fourth method is applied, regardless of which type of divider is used. The spoon method is unsatisfactory for the given criterion (average of admixture -0.77). The most uniform distribution of the admixtures in the wheat seed working sample, by all methods applied, was determined for Hordeum vulgare L. The presence of Polygonum lapatifohum L. was the most difficult to determine by the first (0.40), and the second (0.57) method. The most reliable method for wheat seed working sample formation was the method of