LOS ANGELES, Feb. 4 — Susan Denise Atkins, wearing a purple minidress with a “V” neckline that plunged to her waist, had her trial for the Tate-LaBianca murders put off yesterday until March 30 at the earliest.

Miss Atkins, 21, the member of the hippie cult who turned informer against Charles Manson and his clan, spoke in a soft voice to waive her right to a speedier trial before Superior Court Judge William B. Keene.

Although it was early morning and the courtroom virtually deserted, Miss Atkins was dressed as if for a discotheque. She displayed an eye-popping decolletage. Her shapely legs were encased in white net hose. Her dark hair was brushed smoothly to her shoulders and her fingernails were long and painted silver.

It was Miss Atkins whose testimony before a grand jury led to the indictment for seven murders of the 35-year-old Manson and five other members of his clan, including herself.

Deputy District Attorney Aaron Stovitz told newsmen he felt it would be even later than March 30 before the defendants are brought to trial. Manson’s trial has been tentatively set for Feb. 9 but it was considered certain to be delayed.

Stovitz says it is hoped to try all the defendants together and that the principal cause of delay is that Charles Watson, 24, the other man accused in the slayings, has been successfully fighting extradition from McKinney, Tex., where he was arrested.

Miss Atkins chatted and laughed as she stood beside her attorney, Richard Caballero, in court yesterday. She caught the eye of a male reporter staring at her and crinkled up her nose and grinned at him.

Manson, who is conducting his own defense from his jail cell, says that Miss Atkins — whom he calls “Sadie Glutz” has sent word to him that the district attorney forced her to tell a false account of the five slayings at the Sharon Tate home and the killings of wealthy grocer Leno LaBianca and his wife.

Manson has obtained court permission to confer with his codefendants. Caballero said yesterday that if Miss Atkins so desires he will permit her to be interviewed by Manson before the trial.

By JACK V. FOX