1. Seed testing
viability - the germination percentage
vigor - the ability to germinate quickly, produce “strong” seedling growth with normal morphology, withstand unfavorable conditions
both are measures of “seed quality”

2. Viability tests
direct germ. test (e.g., petri dish test, rolled towel test, soil test)
excised embryo test (e.g., for woodies with certain forms of dormancy)
tetrazolium (TTC) test (detects dehydrogenases present only in living tissue)
x-ray analysis (nondestructive method that detects presence of vital tissues, signs of insect infestation, aging)

3. Other seed tests
verification of species and/or cultivar
% weed seeds
seed health tests
estimating seed vigor

4. Verification of species and/or cultivar
seed size, shape, surface features (useful for species ID)
isozyme (protein) markers (different forms of the same enzyme)
RFLPs (specific nucleotide sequences, cut by specific restriction enzymes)
RAPDs (random DNA segments amplified by PCR)

5. Seed health tests
visual evaluation (e.g., spores or fungal sclerotia, insect presence)
incubation on agar medium
virus testing (e.g., ELISA)

6. Estimating seed vigor
seedling growth rate (avg. no. of days to germination, morphological appearance)
germination under stressful conditions (e.g., cold tests)
others (accelerated aging, electrolyte leakage, etc.)

7. Seedling growth rate
Average no. of days to germinate
E.g., 49% germ. at day 7, 43% germination at day 14; so (49)(7) + (43)(14) ÷ 92 (total germ. %) = 10.3 days