This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Barley seed could be carrying more than the potential for a new crop, with emerging research from the University of Southern Queensland (UniSQ) finding that fungicide-resistant net blotch can be carried on seed and transferred to seedlings. The research provides important evidence of this seed-to-seedling transmission, revealing a previously unrecognized pathway for fungicide resistance to move between crops and seasons.
The finding highlights the role of seed source when managing one of Queensland's most economically important barley diseases. The researchers tested 16 barley seed lots sourced from grower fields across the Darling Downs and detected net blotch pathogen DNA in 13 of them. The team then investigated whether the seed was also carrying markers associated with decreased sensitivity to fungicides, an emerging concern for Queensland barley growers.
Researchers planted one of the higher-risk seed lots and monitored the resulting seedlings. The same types with reduced fungicide sensitivity detected on the seed were subsequently found in net blotch lesions on the seedlings, providing evidence that fungicide-resistant net blotch can move from seed into the next crop. Noel Knight said the finding added an important new consideration to how growers manage the disease.
"Seed isn't just planting material. It can be a disease-management decision," Knight said. "Growers rely on a combination of varietal resistance, inoculum management and fungicides to manage net blotch, but our research suggests seed source should also be considered when managing disease risk." Net blotch can reduce barley grain yields by 10% to 40%, with losses exceeding 40% reported during severe outbreaks.
The disease poses a significant threat to an industry that contributes approximately $190 million annually to the Queensland economy. Knight said fungicide resistance was a growing concern as reduced sensitivity to important fungicide groups emerged in net blotch populations. "If growers are doing everything recommended to manage disease but unknowingly plant seed carrying both the pathogen and reduced fungicide sensitivity, they could be introducing additional disease risk at the start of the season," he said.
The research does not change existing recommendations to choose less-susceptible barley varieties, reduce disease inoculum and rotate or mix fungicides, but suggests seed source may be another factor growers should consider. The researchers found three of the 16 seed lots had no detectable net blotch, suggesting lower-risk seed may be identifiable. Seed testing, which is unavailable for net blotch and fungicide resistance on seed, could help growers make more informed disease-management decisions.
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