River Boyne should roll to Del Mar Derby score

California’s three-year-old turf stars will be in the spotlight in Sunday’s Grade II, $250,000 Del Mar Derby. The 1 1/8-mile event attracted a field of 12. Post time for the Del Mar Derby, Race 8 of 10 on the penultimate summer program at the Del Mar Thoroughbred Club, is 8:35 p.m. EST. Remember to get…