Headed by unbeaten Breeders' Cup Juvenile (G1) and Eclipse Award champion UNCLE MO (Indian Charlie), a total of 364 three-year-olds have been nominated early as prospects to contest the 2011 renewals of the three classic races that make up American horse racing's Triple Crown.

The first of the classics -- the 137th Kentucky Derby (G1) -- is set for May 7 at Churchill Downs in Louisville, Kentucky, followed on May 21 by the 136th running of the Preakness S. (G1) at Pimlico Race Course in Baltimore and the 143rd Belmont S. (G1) on June 11 at New York's Belmont Park. The early nomination period, during which each nomination costs $600, closed on January 22. A late period for nominations, at $6,000 each, will conclude on March 26.

This year's early nomination total is just two less than last year's early total of 366. Six horses were made eligible for the Triple Crown series during last year's late nomination period, which raised the final total of 2010 nominees to 372.

Aside from being the leader in the 2011 class of three-year-olds, Uncle Mo has a chance to give trainer Todd Pletcher back-to-back victories in the $2-million Kentucky Derby. Pletcher notched his long-awaited first Derby win last year with WinStar Farm's homebred Super Saver. Overall, the five-time Eclipse Award-winning conditioner has saddled 28 Kentucky Derby starters.

Owned by New Yorker Mike Repole, Uncle Mo dominated last fall's Breeders' Cup Juvenile at Churchill Downs by 4 1/4 lengths, making him the early favorite for the 2011 Derby. He's expected to make his sophomore debut in the March 12 Tampa Bay Derby (G2).

The list of Triple Crown nominees includes 15 of the 20 horses ranked atop the 2010 Experimental Free Handicap, an annual performance rating of the year's most accomplished two-year-olds. Uncle Mo, currently stabled in Florida, heads that group. It also includes fellow East Coast stars TO HONOR AND SERVE (Bernardini), winner of the Remsen S. (G2) and Nashua S. (G2), and Hopeful S. (G1) scorer BOYS AT TOSCONOVA (Officer); West Coast celebrities COMMA TO THE TOP (Bwana Charlie), hero of the CashCall Futurity (G1), and JAYCITO (Victory Gallop), who took top honors in the Norfolk S. (G1); and Del Mar Futurity (G1) victor J P'S GUSTO (Successful Appeal), now training in Arkansas after moving from his former Southern California base.

Four fillies are among the 364 nominees. The female contingent is led by Hollywood Starlet S. (G1) vixen TURBULENT DESCENT (Congrats), who was unbeaten in three races at two and runner-up in her 2011 debut in the Las Virgenes S. (G1) at Santa Anita. Two Triple Crown races have been won by fillies in the past five years -- eventual Horse of the Year Rachel Alexandra took the Preakness in 2009 and Rags to Riches won the 2007 Belmont Stakes. Three fillies have won the Kentucky Derby, with Winning Colors being the most recent in 1988.

A mild surprise in this year's early roster of Triple Crown nominees is the list includes only six horses from Europe. Trainers Jeremy Noseda, with three nominees, and Clive Brittain, with one, carry the hopes of Great Britain. Irish training star Aidan O'Brien has a pair of nominees.

Notably absent from the roster of nominating owners is Sheikh Mohammed bin Rashid al Maktoum's powerful Godolphin Racing. The Dubai-based operation usually nominates several prospects during the early phase, but Godolphin representatives have informed Triple Crown officials that the stable will wait until after the March 26 UAE Derby (UAE-G2) at Dubai's Meydan Racecourse to decide if any of its horses would be nominated to the 2011 series.

"The impressive roster of nominees to the Triple Crown provides proof that the desire to achieve horse racing's ultimate dream of a Kentucky Derby win and Triple Crown sweep of the Preakness and Belmont Stakes is as strong as ever," said Don Richardson, senior vice president of racing for Churchill Downs. "Despite a difficult economy, a reduction in annual foal crops and other challenges to our horse industry, the Triple Crown's early nominations are basically flat with last year's total. That's a wonderful show of faith on the part of the international group of owners and trainers that have nominated horses to this year's races. We appreciate their support and anticipate a thrilling and memorable Triple Crown series in 2011."

Pletcher leads the list of nominee numbers for the second straight year, but shares 2011's top spot with Hall of Famer and three-time Kentucky Derby winner Bob Baffert. Both nominated 20 sophomores to the Triple Crown. Steve Asmussen, who is searching for his first Kentucky Derby victory but has a pair of wins in the Preakness, is alone in the next spot on the trainers' list with 17 nominations, and filling out the top five are Hall of Famers and multiple Triple Crown race winners D. Wayne Lukas and Nick Zito, both with 12 nominations. Also posting double-figure nomination totals are Kiaran McLaughlin with 11 and Mike Maker with 10. McLaughlin and Maker are seeking their first victories in Triple Crown races.

Other Hall of Fame trainers represented by nominees include Bill Mott with seven; Neil Drysdale and Richard Mandella, each with four; Shug McGaughey with three; and Carl Nafzger and Jonathan Sheppard, each with one.

Darley, another arm of Sheikh Mohammed's worldwide racing operation, leads the ownership bracket with 13 nominees, followed by the partnership of Klaravich Stables and W. H. Lawrence and Zayat Stables, both with eight Triple Crown prospects. Westrock Stables nominated six three-year-olds, while Robert LaPenta, Ken and Sarah Ramsey, Stonestreet Stables and Michael Tabor each nominated five prospects.

Bursting on the scene as leading sire is 2006 Preakness Stakes winner Bernardini with 18 progeny on the list, far outrunning the rest of the pack. Second among the leaders is another young sire, Tapit, with 13. Third on the list is 2010 Triple Crown sire leader Distorted Humor, who sired 10 of this year's nominees. He is followed closely by Dynaformer, Indian Charlie and Lemon Drop Kid, each with nine.

The Kentucky Derby field has been limited to 20 starters since 1975, and accumulated earnings in graded stakes races along the "Road to the Triple Crown" have determined the field for the 1 1/4-mile classic since 1986. The field for the Preakness, the 1 3/16-mile second jewel of the Triple Crown, is limited to 14 starters, while the Belmont Stakes, the "Test of the Champion" and finale of the series at 1 1/2 miles, permits a maximum field of 16 horses.

A Triple Crown sweep -- one of the most difficult feats in all of sports -- has been accomplished on just 11 occasions: Sir Barton (1919), Gallant Fox (1930), Omaha (1935), War Admiral (1937), Whirlaway (1941), Count Fleet (1943), Assault (1946), Citation (1948), Secretariat (1973), Seattle Slew (1977) and Affirmed (1978). Fifty other horses have finished one win shy of the honor.

The 2010 Triple Crown yielded different winners for all three races, although WinStar Farm owned and bred two of the winners. WinStar's Super Saver, trained by Pletcher and ridden by Calvin Borel, won the Kentucky Derby. Karl Watson, Mike Pegram and Paul Weitman's Lookin at Lucky, trained by Baffert and ridden by Martin Garcia, won the Preakness on his way to earning an Eclipse Award as champion three-year-old male. WinStar collected a bookend Triple Crown victory when Drosselmeyer, another homebred, won the Belmont Stakes for trainer Mott and jockey Mike Smith. The Belmont victory was Mott's first Triple Crown win.

The current 32-year streak without a Triple Crown winner is the longest in the history of the series. The previous record was a 25-year gap between the Triple Crown earned by Citation in 1948 and Secretariat's stunning sweep in 1973.