NOTE: Tuesday is the third day of the five-session "Goldman roll," in which the S&P GSCI fund rolls long positions in May grain contracts forward.
Trade awaits the release of the US Department of Agriculture's April supply/demand report at 11 a.m. CDT (1600 GMT).
WHEAT - Down 1 to 2 cents per bushel
Lower in rangebound trade ahead of the USDA's monthly supply/demand report. Improving US winter wheat condition ratings lend pressure.
The USDA late Monday rated 53 percent of the US winter wheat crop in good to excellent condition, up from 51 percent a week earlier.
The USDA said the US spring wheat crop was 5 percent planted, lagging the five-year average of 11 percent.
Profarmer estimated Australia's wheat acreage for the 2017/18 season at 13.4 million hectares (33.1 million acres), down just 1 percent from the 2016/17 season.
CBOT May soft red winter wheat last down 1-1/2 cents at $4.27-1/4 per bushel; K.C. May hard red winter wheat down 2 cents at $4.23-1/2; MGEX May spring wheat up 1 cent at $5.20-1/4.
CORN - Steady to down 1 cent per bushel
Steady to lower as traders await the USDA's monthly supply/demand reports. CBOT May corn retreated after reaching a one-week high at $3.67-1/2 a bushel in early moves.
Brazil's agricultural statistics agency Conab raised its estimate of the country's 2016/17 all-corn production to 91.5 million tonnes, from 88.9 million in March.
Analysts expect the USDA in its monthly supply/demand report to raise its forecasts of 2016/17 US and global corn ending stocks.
The USDA in its weekly crop progress report late Monday said the US corn crop was 3 percent planted, matching the five-year average.
CBOT May corn last down 3/4 cent at $3.66-1/4 a bushel.
SOYBEANS - Steady to up 1 cent per bushel
Steady to firm in rangebound trade ahead of the USDA's supply/demand reports. Rallies capped by the ongoing harvest of a massive South American soy crop.
Brazil's agricultural statistics agency Conab raised its estimate of the country's 2016/17 soybean crop to 110.2 million tonnes, from 107.6 million in March.
Analysts expect the USDA in its monthly supply/demand report to raise its forecasts of 2016/17 US and global soybean ending stocks.
Malaysian June palm oil futures rose 0.7 percent on rising demand and tracking stronger-performing related oils.
CBOT May soybeans last up 3/4 cent at $9.42-1/2 a bushel.