Probable Cause of Discrepancies in Seed Test Results
As a rule the seed testing, results must be accurate and reproducible within comparable limits. However, the results obtained at two different seed testing laboratories may vary, although the same rules are followed. The probable causes are:
1. Heterogeneity of Seed Lots:
This is the most important cause of variation. No two samples taken from the same container or the same lot of seeds are likely to be identical. Inadequate mixing or blending interferes with random distribution and therefore lowers the chances of getting a representative sample form a seed lot. Tendency towards stratification of particle due to varying densities during filling, stacking and transportation of seed containers can lead to sample variations.
Also, genetic heterogeneity , variability in soil and degree of pest and disease incidence during seed maturing combined with variation in operations during harvesting, drying and conditioning are some of the major causes of heterogeity in a seed lot. Utmost care in seed sampling is therefore of crucial importance.
2. Sampling and Equipment:
Defective sampling, substandard equipment and uncontrolled differences in the application of test procedures are the other important sources of variation in test results.
3. Experience:
Expertise of analysts making and or reporting the test results vary. This may also lead to variation.
It should be the endeavour of all seed analysts in the seed laboratory to stick to the procedure prescribed in the rules for seed testing. This would help in bringing uniformity, accuracy and reproducibility in test results.