Seed evaluation plays a fundamental role in determining a seed lot’s potential and planting viability. By evaluating germination and soil emergence vigour we can assess the seed quality. Seed quality can be affected by several different environmental influences including development before harvest, storage, heat disease and pests. Its behaviour cannot be predicted with certainty without testing. From seed analysis key decisions may be made regarding the seed lot. These decisions range from seed use (cropping or feed) to planting rates. Every year we find several seed lots that produce less than 40% viable seeds – this devastating figure was not always predicted, and a surprise once tested.
The optimum time to sample is at or just prior to seed cleaning/grading. This ensures the number of times the seed is going to be handled after the test is kept to a minimum. If the seed viability is questionable then a sample should be tested as soon as possible to reduce time and cost if the seed lot needs to be replaced. It also allows enough time to obtain replacement seed - and to get that tested as well! If a seed test is completed directly after harvest, care must be taken to reduce seed damage through handling and environmental conditions. Seed can be mechanically damaged, but also storage conditions are vitally important. It is also recommended to test again before planting to ensure there has not been any degradation due to environmental conditions.
Number of Seeds
Nutrilab conducts 4 replicates of 100 seeds for both our germination and soil emergence vigour. In essence we only need 1000 seeds to establish both germination and vigour analysis. A composite sample may be obtained from the entire seed lot by taking samples from different positions and combine them.A sandwich bag or 1L ice cream container is adequate for most seeds, please ensure it is well labelled with the grower’s name, seed type and testing required and firmly closed. Seed bags are available free of charge from Nutrilab, please contact us for bags if needed. If a purity analysis is required, we may need more seed. Purity analysis requires a weight estimated to contain at least 2, 500 seeds or over 1Kg for Chickpea and faba beans (120g for Wheat, Barley and Oats). For information regarding any other species please contact our office on 07 46 715155.
The main concern for us is to ensure we receive a random sample of the entire seed lot. This is completed by first taking a primary sample from several bags/silos/containers and combining them to form a composite sample. This is then mixed and randomly sampled to get a working sample to send to the lab. The ideal sampling intensity for testing has been outlined by the International Seed Testing Association.
Sampling Do’s and Don’ts
Turn Around Time
The turn-around time for seed testing depends on what analysis is requested. If purity, germination and vigour are required the test will take approximately 14-16 days depending on quality, weekends and sample volume. Purity and germination are available earlier, but vigour analysis is evaluated at 12-14 days therefore the minimum time taken would be 14 days.
Handling and Transport
The amount of seeds needed for testing is dependent on seed type and analysis. Nutrilab has bags available free of charge but if you are not able to collect them, an approximate guide of a sandwich bag is sufficient for most testing except for large seeds such as chickpea if a purity analysis is required. In this case over 1kg of sample is needed. Once the sample has been collected and placed in a bag make sure it is well labelled with the seed variety, grower name, date and testing required. Seeds may then be sent to the laboratory by any means available, be that mail, courier, friend drop off or in person. We require an order form to be completed either electronically or at the laboratory to ensure we have all the correct details for reporting.