WASHINGTON — Nearby corn futures soared the 40c daily limit April 29 on worries about the effects of delayed plantings after last week’s forecasts for improved weather turned less favorable. Those concerns were borne out later in the day when the U.S. Department of Agriculture in its weekly Crop Progress report showed minimal corn and spring wheat planting progress, and a slight decline in winter wheat conditions.

Corn futures rose 6% April 29, the largest one-day gain in about 10 months, closing at a one-month high of $6.84 a bu in nearby May. Soybean and wheat futures also soared April 29, in part pulled higher by corn prices but also on concerns about tight old crop supplies of soybeans and concerns about spring wheat planting delays and hard winter wheat conditions.

Corn planting in the 18 major states as of April 28 was only 5% completed, far behind 49% at the same time last year and 31% as the 2008-12 average for the date, according to the U.S.D.A. Crop Progress report. Planting in top-producing Iowa was 2% completed, compared with 44% last year and 36% as the average, while No. 2 Illinois was at 1%, compared with 76% last year and 36% as the average. Planting had yet to begin in Minnesota (33% average for the date), North Dakota (12%), South Dakota (12%), Wisconsin (12%) or Michigan (17%).

Spring wheat fared little better with progress in the six major states at 12% planted and 3% emerged as of April 28, compared with 70% and 26%, respectively, a year ago and 37% and 10%, respectively, as the 2008-12 average for the date, the U.S.D.A. said.

Condition ratings for the U.S. winter wheat crop also slipped as of April 28 with 33% of the crop rated good to excellent (35% a week earlier and 64% a year ago), 35% poor to very poor (33% a week earlier and 10% last year) and 32% fair (32% and 26%, respectively). As has been the case all spring, condition ratings in the hard winter states were much worse than those in the soft winter states. In addition to drought conditions, which have improved overall, across much of the hard winter region, there have been numerous frost and freeze occurrences that have damaged the crop in parts of Kansas, Colorado, Oklahoma and Texas.

Kansas wheat on April 28 was rated 27% good to excellent (30% week earlier) and 39% poor to very poor (37%), Oklahoma wheat was 23% good to excellent (27%) and 41% poor to very poor (36%), Texas 7% good to excellent (12%) and 68% poor to very poor (60%), Colorado 11% good to excellent (9%) and 54% poor to very poor (56%), Montana 57% good to excellent (51%) and 10% poor to very poor (12%), Nebraska 12% good to excellent (11%) and 44% poor to very poor (43%), and South Dakota 6% good to excellent (6%) and 51% poor to very poor (53%).