Monsanto flagged the prospect of a drop in South American corn sowings, amid a debate on how significantly lower prices are deterring plantings, and how much of a boost this may give to soybean area.
Brett Begemann, the Monsanto chief operating officer, said that the South American corn seed market was "going to be a lot smaller" for 2017-18.
"That's clear. Third parties saying that acres are going to be down 20-30%," he told investors.
In Brazil, South America's top grower of the grain, the group was "pretty confident corn acres are going to be down in the first season" – or summer corn crop, which is currently being seeded.
"Third parties are confirming that," he said.
For the second, or safrinha crop – which will be planted early next year, typically on land left clear after harvesting soybeans – "we don't anticipate the same kind of decline… that we're seeing in the summer season", Mr Begemann said.
In Argentina, South America's second-ranked corn-growing nation, Mr Begemann signalled expectations of a decline in sowings too, although saying that "we don't see the same kind of reduction" as in Brazil.
Still, the lower corn sowings would open up opportunities for soybean seedings, which the group saw fuelling a rise to 60m acres in South American use of its Intacta Roundup Ready 2 Pro genetically modified soybean seed for next season, up 10m acres year on year.
In Argentina, Mr Begemann said that "I would anticipate that those [lost corn] acres are replaced with soybeans".
Farmers in Brazil "have options to other crops as well", he told investors, although adding that "I would anticipate at this point that in most cases" lost corn area would be switched to soybeans.
The comments come amid something of a divergence on South American corn sowings prospects for 2017-18, with Michael Cordonnier, for instance, the respected crop analyst, seeing total Brazilian corn sowings down 10%.
This forecast factors in "a significant decline in the full-season acreage, maybe 20% or more, and a hold even, or a slight decline, in the safrinha corn acreage, [of] maybe 2% or more", he said, citing observations of "low corn prices and better returns for soybeans".
The International Grains Council last week said that "due to low prices and poor returns, first [main crop] corn sowings in Brazil are expected to drop sharply… as more growers opt instead for soybeans".
Safrinha corn sowings are "projected to show little overall change", the council said.
However, the US Department of Agriculture has forecast a small rise in Brazilian corn area in 2017-18., by 150,000 hectares to 17.7m hectares on a harvested basis.
And in Argentina, the USDA sees a marked rise in corn area, of 300,000 hectares to a record 5.2m hectares.
The IGC also forecasts Argentine corn sowings growing "to a new peak", while the Buenos Aires grains exchange foresees growth in sowings to 5.4m hectares, also a 300,000-hectare rise, on its estimates.
Dr Cordonnier said that Argentine farmers "are expected to increase their corn acreage due to better returns expected for corn.
"The big advantage for corn in Argentina is the fact that the export tax for corn has been completely eliminated, while the export tax for soybeans is still 30%."
Indeed, the IGC saw "limited potential for a sizeable expansion" of Argentine soybean seedings in 2017-18, while the Buenos Aires grains exchange last week forecast a drop in sowings of some 900,000 hectares to 18.1m hectares.
However, the USDA has pegged Argentina soybean area up 750,000 hectares year on year at 19.1m hectares.
For Brazil, there is broader industry agreement, with the USDA seeing soybean area up 800,000 hectares at a record 34.7m hectares, and the IGC saying that soy "seeding is expected to be larger year on year", although adding that "gains may be capped by low local and world prices".
Consultancy AgRural estimates a rise of nearly 2% to 34.56m hectares in Brazilian soybean plantings in 2017-18, although a slow start to seedings, thanks to dry weather in major central growing areas, has raised questions over sowings being curtailed.
By Mike Verdin