PLOVDIV, BULGARIA, AUG. 12 -- Dragutin Topic of Yugoslavia set a world junior high jump record of 7 feet 9 1/4 inches today, highlighting the final day of the third World Junior Track and Field Championships.

Topic bettered by a half-inch the mark set in 1986 by Cuba's Javier Sotomayor, who holds the world record of 8 feet.

The United States won both men's relays with Chris Nelloms of Dayton participating in both to increase his gold medal count to three for the championships. Nelloms ran the first leg as the U.S. team won the 400-meter relay in a meet-record 39.13 seconds, .13 off the world junior record. Reggie Harris, Todd Bridges and James Stallworth carried the baton the rest of the way.

Nelloms anchored the 1,600 relay team to victory in 3:02.26. Harris, Tony Samuels and Derek Mills ran the earlier legs.

Nelloms's other gold came in the open 400, which he won in a meet-record 45.43.

Jamaica won the women's 400 relay in 43.82 and was second to Australia in the 1,600 relay. Australia won the event in 3:30.38 to Jamaica's 3:31.09.

Six meet records were set today, increasing to 20 the number set in 41 events over three days.

Sergei Bykov of the Soviet Union won the triple jump with a mark of 55 feet 8 1/2 inches, Mathew Birer did 8:31.02 in the 3,000 steeplechase and Moses Kiptani of Kenya won the men's 1,500 in 3:38.32. Susan Feitor of Portugal set the only women's mark of the day with a 21:44.30 performance in the five-kilometer walk.