Grainswest - Winter 2024

Winter 2024 grainswest.com 33 “Nowadays, testing labs are easy to access and give you a wealth of information to support your business.” —Devin Hartzler “I think the name ‘vigour’ for the test may have to be changed. We now have all kinds of technology that we can use to test the tolerance, endurance and hardiness of seeds.” Such testing often involves imposing the dual stressors of excessive heat and moisture on seeds in storage to gauge the reaction and impact on performance. “We literally send seeds into a state of panic. We create rapid respiration with heat and moisture, emulating heating and/or longevity in the bin,” said Foster. “If they have strong genetics, some seeds can withstand periods of high temperature and high moisture in the bin for a short time. This is called the accelerated ageing test, and the seeds that perform well will excel in the field.” Assessing vigour can also involve a cold test in which seeds are put into wet soil or sand at low temperatures, 5 C for wheat and 6 C for barley. In this way, testers determine how quickly a seed can develop in a short time under stressful conditions. Then there is electrical conductivity (EC) testing, which looks at seed coat integrity. “Is the seed coat cracked? If so, are they big or small cracks? Are the internal structures of the seed sound?” said Foster. “The EC test measures the amount of sugars and starches that leach into the water from the seeds. This gives us a vigour value for when the seed should be planted, and if it should be planted at all.” TESTING! TESTING! Germination is another critical focus of seed testing, and for good reason, as it gauges the viability of seeds. “For this aspect, we plant seeds under ideal conditions and evaluate them based on the number of seedlings that will turn into normal, healthy plants,” said Webb. Most cereals are tested for germination at 20 C. Grown in sterile media, they receive just the right amount of light and moisture. More testing is better, so farmers will often get a TKW test as part of their seed scrutiny. “If you want a clear idea of where your seeding rate must be to reach your target plant population, TKW is a good choice,” said Devin Hartzler. He farms 3,000 acres of grains and oilseeds on his farm near Carstairs. “How many seeds per linear foot do we need to plant to reach that target?” Even if your seed passes the above tests, it could be for naught when disease strikes. Because seeds can’t take sick days, health can be closely tied to wealth. “Disease testing is valuable for keeping tabs on what pathogens to watch for from year to year,” said Foster. “Some diseases are always present, while other ones vary depending on the weather. For example, in years where there is a lot of moisture during flowering, we often see high levels of Fusarium in cereals. One year may see only a single big disease threat, while others have four or five.” In general, 20/20 Seed Labs focuses on five pathogenic fungi categories that tend to cause the most severe diseases. Cochliobolus sativus causes seedling blight, foot and root rot or spot blotch, also known as leaf blight. Fusarium graminearum is the pathogen behind Fusarium head blight (FHB), which produces Fusarium damaged kernels (FDK). Additional members of the Fusarium genus cause seedling blight, root and crown rot and head blight. Fungi of the Pyrenophora genus cause leaf blight, also known as leaf stripe, net blotch and tan spot, as well as seedling blight in oats. Finally, the Septoria genus causes shrivelled grain similar to FDK, leaf lesions with dark patches and leaf blotch. Foster points out it is not uncommon for between two and five per cent of kernels tested to be infected with any one of these diseases individually. Seeding of cereals when testing determines a Fusarium graminearum infection rate of five per cent or higher, should be carefully considered. When infection levels of any one of these diseases is higher than eight per cent, seed treatments may not provide the necessary control of the pathogen. “A fungal screen is like going to the doctor for a checkup,” said Foster. “As part of the process, we give growers the disease thresholds, so they know when paying for seed