People presumably packed the Emerson Colonial Theatre on Wednesday to hear the Byrds’ Roger McGuinn and Chris Hillman team with country stalwart Marty Stuart and his band to play the Byrds’ entire seminal album Sweetheart of the Rodeo, a 1968 project credited with laying the path for country-rock and alt-country.

Fans basked in that glory, with McGuinn, Hillman and Stuart trading lead vocals on the Nashville-recorded album’s 11 songs, shuffled into a second set. The ad-hoc group struck a natural chemistry, from sweet five-part harmonies on Bob Dylan’s “You Ain’t Going Nowhere” to warm tales about the making of the album – before Hillman’s warm take on the winsome “Hickory Wind,” a song by beloved Sweetheart co-conspirator Gram Parsons. Stuart helped inhabit Merle Haggard nugget “Life in Prison (and matched the twang of Chris Scruggs’ pedal steel on a guitar formerly owned by album session player Clarence White), while the group embraced the gospel flavor of William Bell’s “You Don’t Miss Your Water” and the Louvin Brothers’ “This Christian Life.”

However, before and after the Sweetheart material, the synergy that Hillman and McGuinn shared with Stuart and his Fabulous Superlatives extended to other Byrds material. That included hits “My Back Pages,” “Mr. Spaceman,” and Dylan’s “Mr. Tambourine Man” and Pete Seeger’s night-closing “Turn! Turn! Turn!” — though an encore take on “So You Wanna Be a Rock ‘n’ Roll Star?” seemed a little too grounded. And some of the Byrds’ lesser-known fare brought the best anecdotal treatment, including “Old John Robertson” (about a 1920s film director who Hillman knew as a neighbor) and “Drug Store Truck Drivin’ Man,” which McGuinn said was inspired by a Nashville DJ who made clear he had no interest in playing the Byrds’ version of country on-air.

But the Byrds proved highly influential on a Florida-born, California rocker who adopted McGuinn’s Rickenbacker sound in particular. So the group packed the encore with a tribute to recently departed friend Tom Petty with his “American Girl,” a particularly lovely “Wildflowers” and “Runnin’ Down a Dream,” where Stuart ripped Petty guitarist Mike Campbell’s gear-shifting solo on mandolin — ironically for the night’s most electrifying solo. If participants in this 50^th anniversary celebration of Sweetheart of the Rodeo represented an extended family beyond country pedigree, they came full-circle to later offspring in Petty, also gone yet part of an unbroken chain.