Americana is a friendly, fraternal enough genre that the competition for the annual Americana Honors & Awards isn’t exactly full of cutthroat rivalries. Underscoring all that folksy good will, the highlight of the annual nomination ceremony and webcast Tuesday afternoon in Nashville was a surprise reunion of the classic multi-frontman lineup of the Drive-By Truckers, with current singers Patterson Hood and Mike Cooley joined by ex-member Jason Isbell — something that Americana Association executive director Jed Hilly knew would “make that community go AWOL crazy.”

“Y’all should start a band together, I think,” quipped co-host Joey Ryan, of the Milk Carton Kids, after Isbell sang “Outfit,” a song he wrote and sang for the Drive-By Truckers back in 2003, joined by former partners Hood on harmonies and Cooley on lead acoustic guitar.

The Truckers picked up two Americana Awards nominations, for best duo/group and best album, the latter for their politically charged opus “American Band,” from which they performed two numbers at the ceremony. Isbell got just one nod, for artist of the year; as a current hero of the Americana genre, he lacked for more only because of being between album cycles.

Picking up a leading three nominations was Sturgill Simpson, whose “A Sailor’s Guide to Earth” will contend for the Americana album of the year after winning best country album at the Grammys in February. Simpson is also up for artist of the year as well as best song. Joining the Drive-By Truckers in having two nominations each are Rodney Crowell (best album, best song) and Lori McKenna (artist of the year, best song).

“It’s getting younger,” said Hilly, alluding to past insinuations that the makeshift genre — an amalgam of American roots-based styles including folk, blues, acoustic rock, and alternative country — might have skewed toward too mature a demographic in the past. “But the coolest thing is that, even though I just said it’s getting younger, it’s not ageist. The age span of nominees is twentysomething to seventysomething. John Prine is up for artist of the year after already being a lifetime achievement honoree. To have him and Jason Isbell in the same category, or the Lumineers in the same category with (veterans) Billy Bragg and Marty Stuart, that’s pretty awesome.”

Isbell, who has a new solo album, “The Nashville Sound,” coming out in June, chose not to preview his own project on stage at Tuesday’s ceremony but instead additionally performed a song he co-wrote with his wife, Amanda Shires, who is up for emerging artist of the year (and who, in the smallish world of Americana, happens to be out on the road with Prine).

Also up for artist of the year is Margo Price, who made a big introductory splash last year but is between albums this time around. Prior to the most recent Grammys, the Recording Academy’s blue-ribbon committees put a lot of private debate into how to categorize her and Simpson. They ultimately decided to put Simpson in the country category and Price in Americana, somewhat counterintuitively, since her album skewed considerably closer to traditional country than Simpson’s. The Americana Awards, of course, are happy to claim them both.

The Americana Honors & Awards take place at the Ryman Auditorium September 13, kicking off a five-day Americana conference and music festival in sites around Nashville. A major honoree and performer that Hilly described as “one of the legendary artists in the annals of Americana and rock and roll” is set to be announced Friday.

The complete list of 2017 nominees:

Album of the Year

“American Band,” Drive-By Truckers

“A Sailor’s Guide to Earth,” Sturgill Simpson

“Close Ties,” Rodney Crowell

“Freedom Highway,” Rhiannon Giddens

“The Navigator,” Hurray for the Riff Raff

Artist of the Year

Jason Isbell

John Prine

Lori McKenna

Margo Price

Sturgill Simpson

Duo/Group of the Year

Billy Bragg & Joe Henry

Drive-By Truckers

Marty Stuart & His Fabulous Superlatives

The Lumineers

Emerging Artist of the Year

Aaron Lee Tasjan

Amanda Shires

Brent Cobb

Sam Outlaw

Song of the Year

“All Around You,” Sturgill Simpson

“It Ain’t Over Yet,” Rodney Crowell (feat. Rosanne Cash & John Paul White)

“To Be Without You,” Ryan Adams

“Wreck You,” Lori McKenna

Instrumentalist of the Year

Spencer Cullum, Jr.

Jen Gunderman

Courtney Hartman

Charlie Sexton