The rise of a country star like Barbara Mandrell signals the end of an age in country music: the loss of innocence, maybe, or just the end of adolescence.

The proud amateurism of the country and bluegrass pioneers -- Wilma Lee Cooper, the Carter Family, Bill Monroe -- is making room for the careful professionalism of country-pop stylists like Crystal Gayle. While it once required the first-hand credentials of Loretta Lynn to "sell" the songs of hard times and heartbreak that are country music's stock in trade, nowadays that sincerity rings as clearly in the voice of Linda Ronstadt from Tucson, or Barbara Mandrell, Miss Oceanside, Calif; of 1968.

And if this new sophistication, this urbanizing of the country tradition has troubled the purists, it has gone a long way toward dispelling the teased hair-and-twang stereotype of the country girl.

Barbara Man62306230Opry, Las Vegas, Los Angeles and Amarillo with the same openness and self-assurance. And she plays them in, say, velvet blazer and slacks, not gingham and ruffles. And the hair is her own.

"I've had my run-ins with the stigma of the illiterate, dumb-blond country singer," she admits, with a gesture indicating the high-piled hair and robust silhouette of Dolly Parton. "But you can't be trapped by an image. Or we'd be whatever they want us to be."

Mandrell is one of country music's golden girls, one of a flock of young, attractive (mostly blond) singers with a profitable feel for the crossover audience. She has had a series of emotional hits like "Woman to Woman," "Married But Not to Each Other," "The Midnight Oil." She sings the classic country stories of adultery, betrayal, heartache: "When I'm putting on my makeup, I'm putting on the one that really loves me."

But she is also strong in black markets, a lover of rhythm 'n' blues with a natural R&B voice. Her new single, a remake of Luther Ingram's "(If Lovin' You Is Wrong,) I Don't Wanna Be Right," enters the charts this week at an impressive No. 30.

"I have really eclectic taste in music -- I got back to the hotel after the last radio interview at about 5:30 and turned on the classical FM station -- I mean longhair. And it was just what I needed," she rolls her head back in mock exhaustion. "And in about two hours I turned on the country station, and after that I watched the rock 'n' roll special on television."

In a Washington hotel room, between rehearsals for her concert yesterday with the Air Force Band, Mandrell wears a fashionably informal Aspen pullover and jeans tucked into boots. She is 30 and looks a couple of years younger. Her hair, not a bottle blond but a cooler urban streaking, shags away from her face in a modified Farrah. She does not play with it. 6280ger by the smudge of kohl and the startling whites. She has good, unpretentious bones, teeth that look naturally straight and a small, thin mouth -- sensible rather than sensual. Her face is mobile and her hands expressive, but her eyes remain steady, observant. As she watches her father-manager, or her producer Tom Collins, there is affection in her eyes, and respect -- but peer to peer, always.

She will speak, not proudly but evenly, of her rising career: of the years when she was the guest and not the name star, of the string of steady Top-15 or Top-10 hits that she had to earn before her first No. 1. That is, as she knows, what "professionalism" demands. "You have to build a career. I'd rather someone went into the store and said, 'I want the new Barbara Mandrell song' than 'I want "Midnight Oil" by what's-her-name'."

She began reading music and playing accordion when she was 5. "My first appearance was in my uncle's church. I only knew one gospel song, and when I finished, I thought it was so much fun I just played it again."

At 11 she began playing pedal steel guitar and sax ("The same year I got the steel guitar I got a bride doll"); six months later she played Las Vegas on the Joe Maphis show.

She became a regular on a Saturday night country music TV show in Los Angeles and toured with Johnny Cash in a lineup which included George Jones, the late Patsy Cline and Don Gibson.

About the time she entered high school, her father Irby (now her manager) formed The Mandrells with Barbara, her mother and a couple of hired musicians, including 22-year-old drummer Ken Dudney.

"We were the first country group to start touring the Army bases, and we booked ahead as far as Dad would accept them.We threw in a little bit of everything -- you know how the military is, people from all walks of life. In '64 we toured Hawaii, and in '66 and '67 we spent nine months touring the East -- Japan, Okinawa, the Philippines, Vietnam, Thailand, Guam, Midway..."

In 1968 she married Dudney, moved to Tennessee and signed with Columbia, where she had a steady series of Top-15 and Top-10 hits. But after five years she grew tired of the formula approach to the Nashville sound, and broke away.

"Television kept me alive the year and a half between Columbia and ABC (her current label). I was caught up in all these legal hassles, and I couldn't go into the studio. If it hadn't been for TV, I'd have disappeared." She has appeared on the Mike Douglas and Dinah Shore shows, "Hee Haw," "The Midnight Special." Next week she tapes a John Denver special.

"If I have ever had a problem with the 'dumb-blond' image, I think television worked it out for me," she says seriously. "The only way to overcome a stereotype like that is through exposure."

She gets it, like most country stars, by working at least two-thirds of the year. Her 3-year-old daughter usually travels with her; the 8-year-old son stays home with his father.

Before the end of the month, Mandrell will crisscross the country two or three times in a multi-media blitz -- talk shows and the John Denver television special, the Grammy Awards, radio, newspapers. She's working up material for the next album, and will go back into the studio in a couple of months. Stardom is a slick and demanding business, and a woman cannot be a sometime celebrity.

"I can't take too much time off," says Mandrell mock-seriously. "I get rusty."