Seeds are turned so that the side of the corn kernel closest to the embryo is down against the soil. Seeds are placed on a thin layer of saturated soil on paper towels over a special tray. Some consider it to be a more severe test than the tray method. The saturated cold germination test is another way of determining how well a seed lot will do under unfavorable conditions. An extended cold test is also available which exposes seed to two weeks in the cold instead of one. Seedlings that emerge through the sand/soil mixture are evaluated according to AOSA Rules. The cart is then moved to 25C for five to seven additional days. The seeds are covered with a non-sterile sand/soil mixture and returned to 10C for seven days without light. Two replications of 100 seed are placed on Kimpak® that has been moistened and chilled overnight at 10C.
The cold germination test gives a reasonable idea of emergence under less than ideal conditions. We find that the higher the germination of the seed lot, the less positive effect the sand has on the results. In the instances of fungal problems or extremely dry seed, the sand germination can be markedly higher. For soybean samples, sand germination results are the same or slightly higher than warm germination results. It also aids in uniform uptake of water, especially in low moisture soybean seed.
This test is useful in suppressing some fungi. Sand germ tests are done the same as Warm germination, except that a layer of moist sand is placed over the seeds and Kimpak®. Running these three tests generates a germination result for labeling, a cold test on the blended product to relate to the field, and a good estimate of the germination level of the refuge portion. We will conduct a 400 seed germination test & a 200 seed cold test on the blend, and a separate 200 germination test on refuge seeds. A test can be extended 2 days for slow-growing seedlings.įor carryover RIB corn samples, we recommend sending 5-8 pounds of seed (for a 95/5 blend). A test on any species can be ended at the required germination period if an analyst feels maximum germination has been reached. Corn and soybeans are normally tested at 25☌ (77☏) for 7 days. Tests can be conducted in rolled brown paper towels (8 reps of 50 seeds), on blue blotter paper, on crepe cellulose paper (Kimpak®), and Kimpak® covered with sand. A minimum of 400 seeds is required for an AOSA, NSHS, or ISTA official test. Warm germination tests are used for labeling purposes and give a reasonable idea of field emergence under favorable conditions. ISU Seed Laboratory services include: Standard Germination Testing (AOSA, ISTA), Purity Testing and Noxious Weed Exams, Seed Health Testing (NSHS-Accredited), Trait/AP Testing, Vigor Testing (Cold, Saturated Cold, and AA), Tetrazolium Testing (Viability and Vigor), and Fast Green and Hypochlorite Soak Tests.
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