Floyd Mayweather Jr. retires

Unbeaten world champion boxer Floyd Mayweather Jr. backed out of negotiations for a September rematch against Oscar De La Hoya on Friday by announcing his retirement.

“It is with a heavy heart that I . . . have decided to permanently retire from boxing,” Mayweather Jr., 31, wrote in a letter distributed by his publicist.

“This decision was not an easy one for me to make as boxing is all I have done since I was a child. However, these past few years have been extremely difficult for me to find the desire and joy to continue in the sport.”

Mayweather (39-0, 25 knockouts) hasn’t fought since December, when he knocked out England’s Ricky Hatton in the 10th round of his World Boxing Council welterweight title defense in Las Vegas.

-- Lance Pugmire

GOLF

Ochoa (65) takes lead at LPGA Championship

Lorena Ochoa recorded her lowest round ever in the LPGA Championship, a seven-under-par 65 that gave her the lead at Havre de Grace, Md.

Ochoa, who took the lead with a 20-foot birdie on the 18th hole, was at 10-under 134 and had a one-shot lead over Lindsey Wright, who had a 68.

Tommy Armour III double-bogeyed No. 18 and finished one-over 71 to fall into a six-way tie for the lead at three-under 137 after two rounds of the St. Jude Championship at Memphis, Tenn.

It was the most players tied for the lead at the halfway point on the PGA Tour since a six-way tie last year at the Houston Open.

MOTOR RACING

Kahne wins first pole of the season

Kasey Kahne, who ended a 52-race winless streak two weeks ago at Concord, N.C., ran a lap at 170.219 mph in a Dodge to bump Jimmie Johnson from the top spot for Sunday’s NASCAR Sprint Cup Series Pocono 500 at Long Pond, Pa.

Johnson, the first driver to make his qualifying run, ran a lap at 169.856 in a Chevrolet to hold down the pole for most of the session. Kahne went out 31st and took it away.

Kyle Busch finished second to Ron Hornaday Jr. in a NASCAR Craftsman Trucks Series race at Texas Motor Speedway in Fort Worth, the first of a planned cross-country trifecta to become the first driver to race in all three of NASCAR’s national series at three different tracks on the same weekend.

HORSE RACING

Champs Elysees seeks second U.S. victory

Champs Elysees is the 7-5 favorite in the $300,000 Charles Whittingham Memorial Handicap today at Hollywood Park as he seeks his second win in five U.S. starts.

Hollywood Park will open its gates at 8:30 a.m. and the first simulcast race from Belmont Park will be at 9 a.m. For more on today’s card, go to latimes.com/horseracing.

-- Bob Mieszerski

PRO FOOTBALL

Police say steroid dealer killed himself

A convicted steroids dealer who claimed to have sold drugs to pro football players killed himself, the Dallas County medical examiner said.

Plano police found David Jacobs, 35, and Amanda Jo Earhart-Savell, 30, dead of gunshot wounds Thursday in Jacobs’ Plano, Texas, home. Authorities issued no ruling on Earhart-Savell’s death.

The Oakland Raiders signed running back Darren McFadden, their first-round draft choice, to a $60 million, six-year contract.

OLYMPICS

Panel upholds ban on sprinter Gatlin

Justin Gatlin’s appeal to the Court of Arbitration for Sport on doping charges was rejected, three weeks before the U.S. holds its track and field trials.

Gatlin, whose ban won’t expire until July 25, 2010, had hoped to have it reduced to two years so he could defend his 100-meter Olympic title.

Ducks General Manager Brian Burke has been chosen to run the U.S. hockey team for the 2010 Winter Olympics in Vancouver, Canada, USA Hockey announced.

PRO BASKETBALL

Collins decides to pass on Bulls’ job

Concerned a second tenure as the Chicago Bulls’ coach would spoil their friendship, Doug Collins told chairman Jerry Reinsdorf that he was out of the running.

PASSINGS

White helped Steelers become champions

Dwight White, the defensive end known as “Mad Dog” who helped lead the Pittsburgh Steelers to four Super Bowl titles in the 1970s, died at age 58. Section B