The importance of pulse seed quality
By Donna Fleury
Achieving a high quality pulse crop begins with good seed quality.
Testing seed quality is an important step in maximizing yields and profitability. Knowing overall seed quality helps with important crop input decisions, such as seed treatments, and will help to maximize other crop inputs, such as herbicides, to ensure a healthy vigorous plant stand.
“The two most important factors affecting pulse seed quality are diseases and mechanical damage,” explains Kevin Zaychuk, business development manager with 20/20 Seed Labs in Nisku, Alberta. “Even minor damage on peas for example, can reduce seed vigour and lower germination. Damaged seeds are also more susceptible to pathogens when they are germinating.”
The goal for good stand establishment is to start with clean, high quality pedigreed seed to reduce the risks at planting. Monitoring and improving handling operations can reduce mechanical damage. Also use seed treatments, especially when seeding into cold wet soils. However, seed testing is the foundation for knowing what you are planting.
“It’s very important to do a disease screen as a preliminary scan, along with germination tests,” explains Sarah Foster, president of 20/20 Seed Labs. For pulses, the most important diseases are ascochyta, botrytis, sclerotinia and anthracnose. “We recommend the ‘Complete Disease Diagnostic’ for pulses, which is basically a ‘Fungal Screen’ for pulses. We have developed fungal screens specific to each crop and will only test for pathogens a particular crop could be infected with,” says Foster. The Fungal Screen is specifically designed to identify potentially devastating seedborne pathogens. The test results record the level of infection for each pathogen found in the samples.
“Providing the level of infection of specific pathogens allows the customer to select the most appropriate seed treatment,” explains Foster. “The Fungal Screen results help match the diseases to the right product to take care of the symptoms.” Although there are many good products on the market, Foster encourages growers to carefully read the label and make sure they are getting the right product to match the right diseases.
“The most common disease we see on pulses is ascochyta, which can be very aggressive and can result in substantial yield losses,” explains Foster. Some provinces have set limits of the level of infection to be eligible for crop insurance, but at this time, Alberta has not set limits. Some of the other diseases like anthracnose, sclerotinia and botrytis are seen from time to time, and occasionally stemphyllium. There are some very good seed treatments available to protect seeds even if they are infected with disease.
Foster notes that all of these diseases can lead to fairly substantial yield losses. If it is a year of wet harvest, then there will tend to be more of a spread of those diseases. “The weather during seed maturity is very important and it can have a devastating impact on the quality, longevity and early field emergence.” Diseases can result in seeds that have a brown, pitted appearance, generally spoiling the appearance of the seed.
“If you are buying seed, then you should ask for a Report of Seed Analysis from the seller,” says Foster. “Any retail outlets or seed growers selling seed must have a Report of Seed Analysis available at the time of sale. The Report of Seed Analysis must be conducted within the year of the seed being harvested and will include a guarantee of germination.”
Conduct two germination tests
Foster recommends two germination tests, one immediately after harvest and a second after the seed has been cleaned and treated. “By testing right after harvest, you get an idea of what you have and what the quality of that crop is like,” says Foster. “Testing a second time after cleaning and treating will give an indication of whether or not any further mechanical damage has occurred and whether or not the germination is still there. A lot can happen to these large seeded crops between harvest and seeding operation. They have to be handled with kid gloves.”
The germination test is probably one of the most valuable tests. “With experience, we’ve come to identify symptoms of mechanical damage, frost, diseases, immaturity and even glyphosate damage when used as a pre-harvest drydown option,” explains Foster. “The germination test gives a preliminary indication of seed vigour, and the information can be used to make decisions about whether or not to bump up seed rates, use seed treatments or even find an alternate seed source if necessary.”
Foster is concerned that there may be more mechanical damage in the 2007 harvest. “Many of the peas were harvested early under extremely hot and dry conditions, however, in some areas where fall conditions are wet, some pea crops are sitting in the swath. This is likely going to create some disease problems, as well as mechanical damage.” Chickpea and lentil crops tend to be more prone to diseases, but do not experience as much mechanical damage as pea crops. The key, says Foster, is to take your time, slow down and handle crops gently to prevent mechanical damage. Severely damaged seed will not grow or will produce very thin stands. They are also more susceptible to pathogenic infection.
A complete agronomic package, which would include the Complete Disease Diagnostic, germination, vigour and thousand kernel weight, would give growers everything they would need to know to plant that seed. “In a year, an average grower would spend only about $250 for a complete diagnostic testing service,” says Foster. “If they only wanted a basic germination test and a test for one disease, such as ascochyta, then the cost would be about $80. At $100 to $250 per crop, that is a good investment to ensure you get the best results from the seed planted.”
Growers will want to consider testing their pulse seed quality for the upcoming year, especially in those areas where wet fall conditions may have increased the potential for disease related problems. And heed the advice about handling and reducing the risk of mechanical damage – take your time and handle with kid gloves.
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