Importance Of Testing Retained Seed

Testing retained cropping seed for germination and vigour is one aspect of sowing preparation which is regularly neglected even though it is one of the most valuable. A majority of growers sow their retained seed without fully being aware of what percentage is going to germinate and at what rate it is going to emerge. Knowing exactly how much of your crop is going to emerge has a massive influence on both crop competition with weeds and overall yield.

 

There are many factors which have the potential to impact on the quality of the grain, which in turn reduces germination and vigour. These factors include wet seeds at harvest (sprouted grain), storing grain in the wrong conditions (hot and moist), grain pests (insects and diseases), crop topping (desiccation) and frosted grain. These variables have the potential to affect your seeding rates substantially. To prevent productivity loss influenced by retained seed, it’s essential that you conduct a germination test.

 

There are multiple ways in which you can test the germination percentage of your seeds. The first is to send the seeds away to be tested. Take a certain amount of your grain to your local Western AG branch where the seeds will be sent off to Plant Science Consulting who will conduct the germination and vigour testing. The number of seed which needs to be sent depends on the type of grain. Cereals, Lentils, Chickpeas, Lupins and other similar sized seed → 2 cups, Canola and other small seeds → half a cup, Faba beans and other large seeds → 5 cups.

There is also a germination method which can be conducted at your own home as follows;

  1. Collect 100 (or 50) seeds from each lot to be planted.

  2. Lay four sheets of paper towel on top of each other and moisten (do not drench).

  3. Place 100 seeds on the paper towels about 10mm apart.

  4. Roll up, sandwiching the seeds between the moist paper towels.

  5. Soak a hand towel in water and ring out, then wrap it around the rolled-up paper towel and loosely secure with the rubber bands.

  6. Place in a plastic bag, seal and place in a warm place (such as the kitchen bench near a window) and leave for 5-7 days.

  7. Unwrap and count the number of seeds that have not germinated.

  8. Do your calculation as follows: Germination % = [(number of seeds tested – number of seeds that did not germinate) (multiply by two if you started with 50 seeds).

  9. Ideally, repeat with several samples.

 

Once you have discovered your germination percentage you will then have to work out your 1000 grain weight to achieve your desired plant density. Like germination, 1000 grain weight can be calculated at home by following these steps.

  1. Find a digital electric kitchen scale that weighs +/- 1g.

  2. Select a representative sample of seed.

  3. Place some seed on an A4 sheet of paper near the edge of a table.

  4. Hold an ice cream container under the edge of the table.

  5. Scrape 5 grains at a time over the edge of the table into the container.

  6. Make a mark on the paper at the end of each group of 20. Repeat these groups of 20, 10 times in all, which means you have counted 1000 grains.

  7. Place small container on kitchen scale and tare.

  8. Tip the counted grains and record the reading – this is your thousand grain weight.

  9. Finally to calculate sowing rate use the following formula:

 

Sowing rate (kg/ha) = 1000 grain weight (g) x desired plants /m2 ÷ germination percentage.

 

Armed with this information, you can have the confidence to adjust your sowing rate to ensure that your retained seed will still provide you with your desired plant density. If you require any further information please don’t hesitate to get in touch your local Western AG agronomist today

Article produced by - Spencer Weir, Western AG Horsham

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