World-class marathoner Bill Rodgers will be out to defend his 1978 title against a field of more than 4,000 runners in the seventh annual Cherry Blossom Classic, which begins at 8:30 a.m. next Sunday in West Potomac Park.

Rodgers, who won the 10-mile event last year in a course-record 48:57, will have to deal with at least a dozen others who have cracked the 50-minute barrier, including Jeff Bradley.

Bradle, from Mannheim, Pa., was second behind Rodgers last year and is the 1978 Maryland Marathon champion. Scott Eden, the November Marine Corps Marathon winner from Durham, N.C., and two-time Cherry Blossom winner Carl Hatfield of Philippi, W. Va., also figure to contend.

Julie Shea of Raleigh, N.C., three-time women's winner and course record-holder (56:08 in 1977,) heads a field of approximately 800 female competitors. Shea should be challenged by Mary Aileen O'Connor and Jill Haworth.

A record field of 4,035, representing 27 states and Canada, is registered for the race, which winds around the Tidal Basin and along the bank of the Potomac River. A two-mile "fun-run" will take place the same morning.

Registration for the Virginia 10-Miller Sept. 22 will close April 30 or with the return of the first 2,800 entries.

The Lynchburg race will feature the likes of defending champion Bill Rodgers, 1978 runner-up Dan Rincon of New Carrolton, Olympic gold medalist Frank Shorter, British distance ace Brendon Foster and Silver Spring's Bruce Robinson.

Applications are avaiable at Phidippides Running Center in Rockville and Nike Georgetown.

Bloomingdale's will a 10 kilometer road race April 28 in East Potamac Park for the benefit of the Metropolitan Police Boys and Girls Club.