GroundCover™ Issue: 132 January–February 2018 | Author: Clarisa Collis
Central Queensland grower Paul Murphy says sorghum pre-breeding has helped lift long-term average yields and grain quality on his 2000-hectare property about 40 kilometres south-east of Capella.
PHOTO: Hannah Murphy
Organic grower Paul Murphy says genetic improvements through pre-breeding research have made sorghum a more profitable option on his 2000-hectare property in Queensland’s Central Highlands.
Reflecting on the decades of research now operative in his summer cropping paddocks in a marginal growing area, 40 kilometres south-east of Capella, Paul says he has seen a clear lift in average yields and grain quality.
He says, in particular, continual selection for midge resistance in modern sorghum cultivars through pre-breeding has eliminated yield losses that were, for him, approaching 40 per cent.
By growing midge-resistant varieties yield losses caused by the insect have declined to just five per cent, and sorghum has become a summer mainstay covering a third of the family’s cropping program.
This genetic resistance is an important consideration for Paul and his wife Cherry because their farm’s certified organic status prevents them from using insecticide to control the mosquito-like pest.
The stay-green trait is another genetic improvement that Paul says has made sorghum a more reliable crop, contributing to higher average long-term yields. He says the main benefits of this drought-resistance trait are the plant’s ability to better withstand moisture stress and lodging.
He says the stay-green trait has also helped improve grain quality and appearance: “Without this, drought-stricken plants tend to produce grain that is pinched or small.
“This is difficult to process because it’s prone to cracking and has less nutritional value.
“From a visual perspective, large plump grains are easier to market, especially in high-value export markets for baijiu (sorghum spirit).”
Putting the profitability of this stay-green advance into perspective, Paul says substandard grain could mean the difference between earning $500 per tonne in premium organic markets, compared with $400/t in non-premium markets.
Enhanced grain quality due to stay-green has also seen the farming couple avoid a price penalty of up to $40/t for organic
grain containing more than eight per cent pinched grain.
“We haven’t delivered sorghum containing more than four per cent pinched grain for the past five years, and I think that is certainly because of the improved genetics.”
Paul’s interest in germplasm improvement is twofold: as a grower and also as chief executive officer of a grower-owned seed company, Radicle Seeds Australia. For the past two years, Paul has been growing a new hybrid sorghum variety, Agitator, released by Radicle Seeds Australia. This is a low-tillering cultivar developed using germplasm from the GRDC-funded pre-breeding program led by the Queensland Alliance for Agriculture and Food Innovation.
“Reduced tillering means the plant doesn’t grow extra vegetative biomass so it can channel more of its energy into grain production,” Paul says.
“The pre-breeding program has tested these low-tillering lines as part of its trial program and provided data on parent lines, which we then use to develop hybrid sorghum cultivars.”
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