1044 A PRACTICAL VIGOR TEST

Ideally, a vigor test should provide a reasonably accurate forecast of greenhouse or field quality under a wide range of conditions. A vigor test could provide useful data any time during the different stages of development: Before harvest, after harvest, through handling, natural maturation, and decline. Vigor information on a lot of seed is desirable before distribution and conditioning, after conditioning and before planting. Can one vigor test meet all these needs? The most practical seed vigor test should include several different tests which could be combined and indexed. At the Ransom Seed Laboratory we have developed a series of vigor tests which we combine for a vigor index. We perform four tests: 1. Seed weight or seedling length in pelleted seed. 2. Standard % germination as set forth by A.O.S.A. 3. Stand uniformity index at an early count which includes a photograph of one replicate of 25 seedlings. 4. Stress test: % germination at an alternative temperature. (varies from cold tests to heat tests). No single test is sufficient to communicate seed vigor. If several tests are used to form a vigor index, the actual data for each test should be communicated along with the vigor index, so the user can evaluate the data and utilize the vigor index to its fullest potential.