CHAMPAIGN, Ill. (AP) _ Most corn and soybeans in the Midwest escaped major damage as July ended and August began with a hot blast, though the scorching weather may mean a small reduction in yields this fall, experts say.

Much of the corn completed its critical pollination period before the latest heat and drought, so agronomists said the stress likely would mean somewhat smaller, lighter kernels rather than empty ears.

''The corn crop is basically made,'' said Joel Karlin, a grain analyst with Research Department Inc. of Chicago, but soybeans are in a more sensitive stage.

Pods are forming and beans are developing inside them, so rain and moderate temperatures are important. Stress can mean fewer pods or smaller beans.

But soybeans have a greater ability to wait for good weather.

''We got rain ... in just the places where we really needed it, and I don't think it was too late to recover the crop,'' said Janice Kincheloe, market information manager for the American Soybean Association in St. Louis. ''Beans are very resilient, and if we have showers from here on out, it will be a very good crop this year.''

The heat wave broke in many places this week.

Ralph Raber was cool and comfortable Wednesday and relieved that the latest heat wave, with temperatures around 100 degrees, apparently did no serious damage to his 500 acres of crops.

''I don't think we were hurt all that bad,' said Raber, who farms at Mount Carmel in Southern Illinois. ''It really cooled off last night and I was elated.''

''The weather does not look like it will go back into a period of extended heat and humidity,'' said Tom Atkins, meteorologist for Freese-Notis Weather, a private forecasting company in Des Moines, Iowa. ''I think this (heat) was a lot more detrimental to human beings than to agriculture.''

Corn and soybean prices declined on the Chicago Board of Trade.

The U.S. Department of Agriculture will issue its first official estimate of corn and soybean yields and production Tuesday.

The vast majority of the corn and soybeans in the big producing states were listed in good or excellent condition by the government this week, though there were some isolated fields with serious problems.

''We never did hit a period of dry weather that caused us real damage but we were very close to a drought situation,'' said George Howse of the Minnesota Agricultural Statistics Service.

''Now, the corn and beans look tremendously good,'' said Howse, noting that 74 percent of the corn and 72 percent of the soybeans were in good or excellent condition in Minnesota.

''I think the hot weather hit after most of the corn was pollinated, so I don't think there was much problem there,'' said Mike Hunst of the Indiana Agricultural Statistics Service. ''We have been getting frequent showers and they have covered most of the state.''

In Indiana, Hunst said 91 percent of the corn and 89 percent of the soybeans were in good or excellent condition.