TRAINER PETERSON ON A ROLL.

Byline: Daily News Wire Services

Trainer Doug Peterson will challenge Triple Crown participants Victory Speech and Alyrob with late-developing Don't Blame Rio in Sunday's $100,000-added Lazaro S. Barrera Stakes (Gr. III).

``He's a very determined horse,'' Peterson said. ``I claimed him for $32,000 and I moved him up the ladder to run against stakes horses like Odyle and Hesabull in strong maiden fields. A lot of horses will go the wrong way when they are overmatched, but he has plenty of determination.''

Peterson's small stable has been firing of late. He has saddled five winners from 13 starters since the beginning of Oak Tree, for a win percentage of 38.5. The wins include the Colorado King with Don't Blame Rio, the Cal Cup Starter Handicap with Reality Changes, and a $49,000 allowance with Sonic Boy, all horses he claimed in the past year.

``I've been struggling with 10-12 horses for some time,'' Peterson said. ``But hopefully my hard work will pay off.''

The former trainer of Seattle Slew haltered Don't Blame Rio in December of 1995. The 3-year-old has bankrolled $114,700 for his new connections.

``Horses like Seattle Slew are few and far between,'' Peterson said. ``But that's why I work hard and show up everyday. You hope another good horse comes along, but I also enjoy the good horses in between. To take a horse like Don't Blame Rio, whom I claimed for $32,000, and see him develop into a stake horse - that is something I take pride in.''

In other developments:

Victory Speech, who will be making his 14th start of the year in the Barrera, has raced at 11 different tracks in 1996. The frequent traveler, who has raced in seven states and one province in U.S. and Canada, has logged approximately 12,250 miles shipping this season.

Earl Of Barking is retired:Millionaire Earl Of Barking, who won the Hollywood Turf Handicap (Gr. I) in 1995, has been retired.

``He's done nothing but good for a long, long time,'' trainer Richard Cross said. ``I would have liked to run him in the Citation, but he had some small problems. But for a neck, he would have gone out a winner.''

The 6-year-old son of Common Grounds finished second behind Beau Jingles in his last start, the Henry P. Russell on Oct. 12. His greatest success came at Hollywood Park, where he had four wins and earnings of $802,474 from 13 starts. The Irish-bred arrived here for the turf festival in 1992 and won the first Hoist The Flag (now the Generous). He retires with nine wins, three seconds, 10 thirds and earnings of $1,230,554 from 37 starts.