Studies on the Rapid Methods for Evaluating Seed Vigor of sweet Corn
Since the germination test is still the main method for evaluating seed vigor of sweet corn, it is necessary to study the rapid methods for evaluating their vigor. First, two vigor levels of 9 super sweet corn and 9 sugar enhanced corn hybrids were distinguished by accelerated ageing treatment. Next, their vigor statuses were tested by rapid methods such as electrical conductivity (EC), soluble sugar (SS), volatile aldehyde (VA), dehydrogenase activity (DA) and Q2 oxygen sensing technology. Correlation relationship was analyzed between the above tested values and vigor performances. The results showed that EC, SS, VA, DA, oxygen metabolism rate (OMR), critical oxygen pressure (COP) were all suitable to evaluate seed vigor of sweet corn. Furthermore, VA was optimal for evaluating seed vigor of super sweet corn. DA was optimal for evaluating sugar enhanced corn.
Vigor Tests Used to Rank Seed Lot Quality and Predict Field Emergence in Four Forage Species
Laboratory and field tests were conducted in 1999 and 2000 in Gansu Province, China, to investigate the suitability of various laboratory vigor tests, to rank quality of commercial seed lots, and to predict seedling field emergence (FE) of four forage species. Species used included two legumes, purple vetch (Vicia benghalensis L.) and alfalfa (Medicago sativa L.), and two grasses, sudangrass [Sorghum bicolor (L.) Moench subsp. drummondii (Steud.) de Wet ex Davidse] and Siberian wild ryegrass (Elymus sibiricus L.). Results showed that among all tests, the electrical conductivity (EC) test provided the best estimate of seed vigor for the two legume species, both for ranking seed lots quality and predicting FE, but gave the worst indication of seed lot vigor for the two grass species. The EC result was not only poorly related to FE, but also poorly related to the standard germination (SG) of a wide range of seed lots of the two grass species that varied in viability. The controlled deterioration (CD) test generally better indicated seed lot vigor for test species than did SG, except that it lacked sensitivity in ranking seed lot quality of alfalfa and was not significantly related to Siberian wild ryegrass FE. The germination index (GI) better indicated seed lot quality and predicated FE than SG of sudangrass over the 2-yr results, but not consistently better than SG for other species. Initial count of standard germination (SGi) generally performed more poorly than the other vigor tests. From this study and previous work on forage species, we conclude that EC test for forage legumes and CD tests for both forage legumes and grasses have the potential to be developed as improved vigor tests for ranking seed lot quality and predicting seeding performance.
Use of seed vigour tests to predict field emergence of lucerne (Medicago sativa)
Abstract The suitability of three vigour tests (electrical conductivity at different soaking periods, controlled deterioration at 20% seed moisture content, and germination index) for indicating field emergence of lucerne seed lots was studied using 10 seed lots with similar germination percentages. The seed emergences were assessed in glasshouse pot trails using field soil at 30, 50, 70, or 90% soil water‐holding capacity (WHC), and in field plots at two sowing dates. The seed lots differed significantly in seed vigour and in seedling emergence. The lower vigour seed lots had the lower seedling emergence rates both in the glasshouse and in the field. The standard germination test and the germination index did not show any significant correlation with seedling emergence in any glasshouse or field trial. Compared with the standard germination test, the electrical conductivity test was the most reliable for predicting seedling emergence in drier soils with significant correlation coefficients of r = ‐0.701 ...