Wheat and soybean futures have had something of an inverse relationship going on.
The correlation between the two, which topped 0.8 in July, meaning that both grain and oilseed tended to move in the same direction, has collapsed, topping a negative 0.8.
That means wheat and soybeans have been moving in opposite directions.
"There is a very clear negative correlation between wheat and soybeans which began late in September," one US broker said.
"More often than not when wheat was higher, soybeans were lower, and vice versa."
'Buying beans and selling wheat'
The explanation, the broker said, is down to inter-commodity spreading, with hedge funds, which had built up large short wheat-long soybean positions over the summer, unwinding them.
"As the US government shutdown persisted, managed money was likely hedging or lowering their positions due to the uncertainty.
"Now that the shutdown is over and we are past the halfway point for bean harvest, the funds are back to buying beans and selling wheat, at least partially back."
However, as so often happens on markets, no sooner had a trend been observed that it broke down.
Both soybeans and wheat moved in the same direction in early deals on Tuesday, downwards, as traders factored in the first batch of US Department of Agriculture crop progress data in three weeks.
While bulls have been hoping for support from ideas that the USDA shutdown, as part of the government's temporary closure, allowed a barrage of export sales to go unreported, on crop progress, it is bears who gained an advantage.
The report, released late on Monday, showed the soybean harvest progressing even more strongly than had been hoped, with 63% completed as of Sunday.
While behind the average of 69%, traders had expected a figure of 60%, given the slow development of the crop, a reflection of a late sowing period and a cool early summer.
On condition, US soybeans were rated 57% "good" or "excellent", up four points from the previous data, three weeks ago, indicating late-season improvement down to rains after a dry August.
For wheat, plantings of winter crop were shown 79% complete, bang in line with the average pace.
On condition, a healthy 65% was seen good or excellent.
The data, for soybeans, added confidence to cautious ideas that the US yield will end up higher than the 41.2 bushels per acre expected by the USDA, with estimates ticking towards 42 bushels per acre.
And, with rains improving prospects for South American sowings of the oilseed, November futures ticked 0.8% lower to $12.93 a bushel in Chicago as of 09:15 UK time (03:15 Chicago time).
For wheat, for which a cessation in rains is a price-negative factor, in boosting prospects for Russian seedings, the December contract fell 0.5% to $6.96 ¼ a bushel.
Russian data overnight showed the challenge that the country's farmers face, having sown 13m hectares, 80% of the total expected, compared with 15.5m hectares a year earlier, and with the sowings window closing.
South American influences
Meanwhile, wheat investors also have to factor in Argentina's admission that its lowball 8.8m-tonne crop forecast, which lifted prices back above $7 a bushel to four-month highs, was erroneous.
Or was it? There is one theory that Argentina withdrew the data only to quell fears of a ban on wheat exports that may have hurt the ruling coalition's popularity (further) in the run-up to mid-term elections on Sunday.
Meanwhile, Brazilian rains, while helping row crop seedings, are a further negative for a wheat crop which has already been damaged by frost, coming late enough in the growing season to raise fears for protein leaching.
"I expect the trade to turn some focus to the wet conditions that may threaten the quality of the Brazilian production," Brian Henry at Benson Quinn Commodities said, if saying he was cautious over the prospect for further price rises for now, saying that "the market needs a better correction".
Corn futures dropped too, but less so, down 0.2% at $4.43 ¼ a bushel for December delivery, given some support by confirmation of a slow US harvesting pace.
Just 39% of the crop was in the barn as of Sunday, below an average of 53%, and less than half the proportion harvested a year before, the crop progress report showed.
That said, it also revealed improving corn condition, with 60% rated "good" or "excellent", up five points from the previous report, three weeks before.
Prices are gaining support from increased competitiveness on export markets, with Ukraine prices buoyed by that country's own harvest delays, and from a solid domestic basis as growers, who have got used to higher prices, withhold sales.
Among soft commodities, the sugar market had yet another influence to deal with when Unica overnight revealed data showing a 31% drop, year on year, on output of the sweetener in the first half of October, reflecting a rain-slowed cane harvest.
Furthermore, Chinese data revealed imports of 591,900 tonnes, up 1.1% year on year and 4.5% month on month – not huge rises, but larger than analysts had expected some months ago when China's imports were seen declining.
Still, raw sugar for March declined, but by a modest 0.2% to 19.38 cents a pound in New York.
Back among oilseeds, palm oil added 1 ringgit to 2,348 ringgit a tonne in Kuala Lumpur, continuing to rise on decent Chinese economic data.
"The market is confident that demand for the world's second-largest palm oil consumer is likely to pick up in the upcoming months," Phillip Futures said, if cautioning itself over the influence on the market from a strong Indian oilseeds harvest.
Industry data show that India's monsoon oilseed crop "is likely to rise 11% to 16.9m tonnes due to increase in the area under cultivation and better monsoon rains," the broker said.
"The forecast of better oilseed yield in India may reduce demand for palm oil imports and hence add pressure to palm oil prices."