The Federal Court has ruled a seed marketing business was sowing dishonesty when it claimed a new variety of barley was stronger and more tolerant to disease.
Landmark-owned Seednet has copped a $1 million fine for telling farmers between December 2014 and December 2016 the Compass variety of barley was able to stay upright better than an older product.
For a year, the business also distributed fact sheets that claimed Compass had more resistance to debilitating leaf rust than it actually did.
The Australian Competition and Consumer Commission, which initiated proceedings against Seednet in August, said the company's conduct had denied grains producers the chance to make an informed decision about what they put on their farms.
"Exaggerated marketing of new agricultural produce is a major concern across the industry," ACCC deputy chair Mick Keogh said.
"At the time of the release of a new crop variety, farmers and their agronomists lack other sources of independent information beyond what businesses tell them."
The Federal Court also ordered Seednet pay $50,000 as a contribution to the ACCC's legal costs.
Leaf rust is a plant fungus that can severely affect barley crops, particularly where a crop is left untreated.