Western Australia
October 8, 2014
DAFWA senior research officer Dr Bob French examines an early sown wheat plot at the Merredin Research Facility. Research has shown significant gains from planting large seed when sowing deep.
Seed size can have a significant impact on the successful establishment and profitability of a wheat crop, according to the preliminary results from a series of field trials.
One of the trial sites, featured at the Department of Agriculture and Food’s recent Merredin Research Facility field day, showed that larger seed had a much greater effect on crop establishment than variety when sown deep.
Department senior research officer Bob French said the size of the seed was particularly important for growers who chose to chase subsoil moisture.
“The trial at Merredin and another at Buntine showed that while seed size had very little effect on crop establishment when sown at a conventional depth of 40mm, there was a much greater difference when sown deep at 75mm,” Dr French said.
“Establishment at Merredin was reduced by as little as 19 per cent when sown deep with large seeded Mace or as much as 63pc when sown with small Wyalkatchem seed at Buntine.”
Another trial at Mullewa had similar emergence results from being sown in 80mm of soil with marginal moisture.
“Here the use of small seed reduced establishment by as much as 50 per cent compared with large seed of the same variety,” Dr French said.
Previous department research suggests varieties with longer coleoptiles – the pointed protective sheath that encases the emerging shoot as it grows from the seed to the soil surface – will emerge better from deep sowing.
“Our results show that within the same variety large seeds have longer coleoptiles,” Dr French said.
“Large seed also produces more vigorous seedlings that are better able to tolerate early stresses – so there are benefits to be gained when sowing at normal depth too.”
The results reinforce the department’s recommendation to growers to grade out smaller seed and retain larger, quality seed from well grown crops.
“We would suggest growers use seed that weighs at least 35 grams per thousand seeds and preferably more than 38, especially if sowing deep,” Dr French said.
“Selecting good quality seed is one of the few pre-sowing strategies growers can use to optimise their crop potential before sowing, particularly for those facing dry conditions or a late break.”
These trials were funded by the Grains Research and Development Corporation and the results will be presented at Crop Updates in 2015.
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