Australia
March 7, 2011

Saving viable grain seed for the 2011 winter crop following such a wet harvest period requires careful collection, storage, handling and subsequent planting.

Grains Research and Development Corporation (GRDC) northern panellist and cereal chemist, Jodi McLean, says retained seed must be graded and tested for germination and vigour.

“All crops are susceptible to deterioration in seed quality during wet harvests,” Mrs McLean said.

“Symptoms can range from mild – a loose and wrinkled seed coat, to severe – seed staining and fully germinated seed.

“It is essential to recognise whether the damage is cosmetic or the symptom of a seed-borne disease and if it will impact on germination.”

Seed quality can also decline during storage and growers are advised to test germination capacity before and during storage, and before planting.

“Generally, a germination percentage of 80 per cent at planting is considered acceptable but when testing at harvest the germination percentage should be higher,” Mrs McLean said.

With many weedy pulse and cereal crops in a wet season, desiccation or crop topping is often necessary. Depending on timing and chemicals used, this could affect seed quality for sowing.

Growers are reminded that grain must not be retained for seed when glyphosate has been used in pre-harvest applications.

“Achieving and maintaining low temperature, humidity and grain moisture content for stored grain is critical if grain has been weather damaged,” Mrs McLean said.

“As weather damaged seed deteriorates faster than sound seed it should not be stored for more than 12 months.

“A germination test can be carried out on stored grain one to two months after storing to reassess its viability.”

Weather damaged grain is likely to have a lower germination percentage and poorer vigour, so seeding rates will need to be adjusted accordingly.

A laboratory seed test should be used to establish the germination percentage of on-farm retained seed before sowing, especially if it has been weather damaged. A vigour test is also recommended.

Purchased seed will be certified and should include details of germination percentage.

“It is essential that nothing impedes germinating seed to reach the surface and establish,” Mrs McLean said.

"Sowing too deeply, cold or wet soil, some seed dressings and herbicides and hard setting soil, can all reduce seedling emergence.”

Top tips for seed retention include:

• Ideally retain seed from grain harvested before rain.
• Weather damaged grain is more susceptible to poor germination, low vigour and degradation during storage and handling, so extra care is needed.
• Harvest at low moisture and cool temperatures. Storage temperature and moisture must be monitored and controlled.
• Germination percentage should be checked at harvest, during storage and before seeding. Low germination seed should not be used.
• Do not retain seed from hybrid canola.
• Correct seeding depth, conditions and agronomy are essential when sowing weather damaged seed.

GRDC has released a fact sheet, Retaining Seed, outlining tips for saving seed and answering frequently asked questions. It can be downloaded from www.grdc.com.au/uploads/documents/GRDC_FS_RetainingSeed2.pdf.
 

Website: http://www.grdc.com.au

Published: March 7, 2011