Melaine Walker, the defending champion in the Olympic Games women’s 400m hurdles, led the qualifiers after this morning’s first round heats as the JAAA/Supreme Ventures Limited National Senior Trials got underway with a shaky start at the National Stadium.

Despite several small glitches, the most anticipated national trials on the globe got off as anticipation builds for this afternoon’s appearance of double World Record holder Usain Bolt and a cadre of world class sprinters in the men’s and women’s 100m events.

This morning Walker shook off a subpar performance on the European circuit to clock 54.88 seconds, the only sub 55 seconds timing of the day going into tomorrow afternoon’s final.

Kaliese Spence, the 2011 IAAF Diamond League winner, ran 55.92 seconds to win her semi-final heat while Daegu World Championships semi-finalists Ristananna Tracey struggled home in 57.92, the eighth fastest time of the day.

Holmwood Technical schoolgirl Janieve Russell also qualified for the finals with a personal best 57.04 seconds.

Josef Robertson led the men’s qualifiers with 50.03 seconds ahead Roxroy Cato, the top Jamaican this year running 50.09 seconds with Bryan Steele’s 50.14 seconds also advancing.

Defending champion Leford Green — 50.57 seconds, and Isa Phillips, also advanced.

Meanwhile, eight qualifiers from the men’s first round of the 100m will join the 24 seeded runners including Bolt and World Champion Yohan Blake in the quarterfinals later today.

Ramone Nichol, Bernardo Brady, Marlon Robinson, Omar Douglas, Rasheed Dwyer, Andrew Fisher, Adolphus Nevers and Andre Wellington all advanced.