Before they yodeled and hen-clucked their way on to radio shows heard by millions, Mary Jane and Carolyn DeZurik were typical central Minnesota farm girls growing up amid rolling fields six miles east of Royalton.

Granddaughters of Slovak immigrants, they were among seven siblings who milked cows, baled hay, canned vegetables and cleaned the barn and the house. Their father, Joe, played the fiddle and their brother, Jerry, squeezed an accordion. Before long, the sisters were singing and strumming guitars at local barn dances and the Morrison County Fair in Little Falls.

That's usually where early country music stayed — dusty hyperlocal venues such as church basements, barns and bandstands. But the DeZurik sisters would help pioneer country music into the national obsession it is today.

Coming of age during the Depression, the sisters joined the flock of rural kids escaping the increasingly hardscrabble agriculture life for the opportunities available in the big cities. They never forgot their farm upbringing, though, parlaying their past into big-time success.

In 1934, everything changed for these seemingly ordinary teenagers — as Carolyn recalled in a 2003 interview six years before her death at 90. Royalton, she recalled, had a band that played every Wednesday night, led by the town dentist and featuring their Uncle Frank.

"We saw this truck coming up the road and Uncle Frank walked over to us with a big grin on his face and asked us if we'd like to sing with the band tonight. We said: 'What?' "

The girls grew up singing — often imitating the bird songs they heard over the fields and around the chicken coops. Carolyn told her uncle they weren't good enough to sing in public. "But he insisted. He pushed us into it."

With no microphone, the girls sang that night — yodeling in their dizzying array of trills. When they finished the first song, the crowd went berserk. "They screamed. They howled. It was a big success."

Within a couple of years, they were dazzling audiences at the county fairgrounds in Little Falls — where a talent scout named George Ferguson for Chicago's WLS radio station happened to be in the crowd. WLS, which was owned by Sears and Roebuck, stood for World's Largest Store and dominated Midwest media in the pre-television era.

Ferguson signed on the sisters in 1936 and put them on the wildly popular National Barn Dance radio show. Before long, they'd be regulars at the Grand Ole Opry in Nashville.

They moved to Chicago, laughing at their sudden success, which they attributed to those days on the farm.

The country music world took them seriously. They were among the first female country stars unaccompanied by fathers or brothers on stage.

"They specialize in trick yodels," one fan magazine said, rattling off the Hawaiian, Swiss, German and "triple tongue yodel and cackle trill" in their vocal arsenal.

Today, yodeling is all but forgotten. But in the 1930s and '40s, it was huge. Louisiana music writer John Biguenet, who has written extensively about the DeZuriks, calls their act "in-between" music.

"Though their yodeling is astonishing and sometimes exhilarating as they rise to shattering heights together, it is in their beautifully matched voices, where one barely shadows the other, that the extraordinary quality of their music becomes apparent."

When the girls were single, one fan magazine described Mary Jane as "just five feet tall," one inch shorter than her younger sister, Carolyn. Both had "blue eyes and light brown hair," often curled up tight.

"Neither girl is married and both insist they have no intentions of wearing orange blossoms soon," one story declared.

But by 1940, both DeZurik sisters got hitched. Ralph (Rusty) Gill, a WLS guitarist and member of the Hoosier Sod Busters, first met the sisters at the Morrison Country Fair. He worked with them for two years before realizing that "I was keeping my eye on Carolyn."

Mary Jane wed WLS accordion player Augie Klein a month later. Shortly afterward, the girls from Minnesota were off to Hollywood, starring in Republic Pictures' movie "Barnyard Follies."

The DeZurik sisters proved to be as flexible as they were talented. When Purina Mills' talent folks heard them sing "My Little Rooster" on the WLS National Barn Dance, they decided the sisters would be perfect pitch people for their chicken feed. The sisters did an end-run around their WLS contract — renaming their act the Cackle Sisters and starring on the Purina-sponsored "Checkerboard Time" radio show heard in 48 states.

Both had children in the early 1940s before their husbands went off to World War II. Carolyn won an audition to join the Sonja Henie Ice Review — opening the former Olympic skater's ice follies with a spotlight yodel.

In 1947, Mary Jane was injured in a car accident and retired. Their younger sister Lorraine filled in. And by 1956, Carolyn was reinventing herself again.

As yodeling's popularity faded, she traded in her cowboy boots and hats for Bavarian clothing and started singing polka music with a retooled act called the Polka Chips.

Mary Jane died in 1981 and Carolyn outlived her by 28 years. They are buried in suburban Chicago cemeteries 40 miles apart — and 400 miles from the rolling Minnesota farmland of their childhood.

Curt Brown's tale on Minnesota's history appears each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com