This episode's headline: Midwest Drought. The guests include CAROL BROOKINS, Grain Analyst; BILL ROENIGK, National Broiler Council; In Des Moine, Iowa (Facilities: Iowa Public Television): Gov. TERRY BRANSTAD, Republican, Iowa; JERRY KINCART, Farmer. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; JOE QUINLAN, Producer; MARIE MacLEAN, Reporter