Queensland researchers have discovered genes in sorghum which could increase grain size without any penalty.
Bigger grains could mean higher yields, fewer screenings, improved digestibility and better milling efficiency.
Led by Professor David Jordan, the work has been done by The Queensland Alliance for Agriculture and Food Innovation - a research institute of University of Queensland - at the Hermitage Research Facility in Warwick.
"New variants have been identified that are capable of doubling grain weight," QAAFI researcher Dr Yongfu Tao said.
"These traits are strongly inherited, with genes accounting for as much as 80 per cent of the grain size characteristics."
Dr Tao said 125 regions in the sorghum genome had now been identified where variation in the DNA sequence was associated with grain size and response to environmental conditions.
"Genetic makeup largely determined an individual sorghum plant's grain size, however environmental conditions also had an effect," he said.
"This allows us to identify the genetic control of grain size with minimal change to environmental resources, such as water or nitrogen."
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Dr Tao said grain size was an important quality trait and a major yield component for grain sorghum, with larger seeded varieties preferred by farmers.
However, the improvement of grain size was complicated by the negative correlation with grain number.
"If sorghum improvement is only focused on grain size, you are likely to reduce grain numbers, therefore having a yield penalty," he said.
"But if you are only focused on grain yield, you are likely to have smaller seeded genotypes, which is not what farmers want either.
"So identifying those genes working on grain size itself and working on the negative correlation between grain size and grain number, we're offered the opportunities to improve grain size and yield at the same time."
For Darling Downs grain grower Jason Mundt, sorghum varieties need to tick several boxes before he will consider them for his farm.
"We look for standability, yield, quality, screenings - it has to be the whole package," Mr Mundt said.
Mr Mundt, who farms at Mundalee, Yandilla, said that was especially true in the last few seasons.
"In the last few tough summers, we needed our varieties to deliver for us. It's not just about top-end yield," he said.
Upon hearing about the new research, the grower said he would be happy to try it.
"I embrace technology and I'd definitely trial it if it got close to the commercial stage, but I wouldn't have the whole place dedicated to it," he said.
"It's trial and error.
"I'd also want to know about its standability and weathering."
He said bigger grains would be easier to mill and could reduce screenings.
"If you've got a big grain, you're reducing the sorghum two market, which is at 11 per cent screenings and higher," he said.
"Whether that is a good or bad thing, it depends on the markets."
Mr Mundt's moisture profile is currently sitting around 90 per cent, but he was waiting on rain before he started sowing this year's sorghum crop.
"I bought my seed back in August, but we need about 50mm across the district before we get underway," he said.
"We were very lucky to get that winter rain. Getting rain in that June/July period is like getting 200mm in summer because you don't have that evaporation."
The grower plans to sow 80 hectares to Resolute and 420ha to MR-Buster to land, which is one year fallow out of wheat.
Mr Mundt usually plants in late September into October - soil temperature permitting - and harvests about late February into March.
He'll use a John Deere MaxEmerge planter at a seeding rate of 70,000 to 80,000 seeds/ha.
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Brandon Long
Brandon Long is a Queensland Country Life journalist based in Toowoomba.
Brandon Long is a Queensland Country Life journalist based in Toowoomba.
