Lionel Richie’s country collaborations “Tuskegee” sat tight at No. 1 on the U.S. album chart this week for a second consecutive frame.Featuring duets with Blake Shelton, Rascal Flatts, Tim McGraw et al., collection shifted 114,000 in its fourth chart week (off 11%), according to Nielsen SoundScan figures for the week ended April 22. Title debuted at No. 2 three weeks ago and has moved 537,000 units to date. Pop/R&B vet Richie’s numbers were strong enough to stave off a challenge by Jason Mraz’s “Love Is a Four Letter Word” (Atlantic), which bowed at No. 2 with 102,000 sold. The pop vocalist’s previous high-water mark came four years ago, when “We Sing. We Dance. We Steal Things” topped out at No. 3. Adele’s champion performer “21″ (Columbia) showed a small 2% sales drop, losing a rung and taking No. 3 with 90,000 shifted in its 61st week. Smash-hit package is homing in on the 9 million sales plateau with 8.82 million sold to date. Train’s new “California 37″ (Columbia) made an anticipated strong debut, kicking off at No. 4 with 76,000 moved out of the box. It’s the Bay Area group’s first release since its 2009 radio ubiquity “Hey, Soul Sister.” Holdovers bunched up in the middle of the chart with slipping numbers: U.K. boy band One Direction’s “Up All Night” (No. 5, 55,000 sold, off 18%), Nicki Minaj’s “Pink Friday: Roman Reloaded” (No. 6, 48,000, down 40%) and Gotye’s “Making Mirrors” (No. 7, 44,000, off 18%). Rapper Future was the week’s only first-time top 10 entry, as his debut album “Pluto” (Epic) took No. 8 with 41,000 shifted. The Atlanta-bred performer aka Navyvadius Wilburn, a veteran of the Dungeon Family rap posse, was previously repped in the market by self-released mixtapes. Bonnie Raitt’s “Slipstream” (Redwing) dropped three poles in its second week to No. 9, tracking 35,000 units (off 45%), while country singer Luke Bryan’s “Tailgates and Tanlines” (Capitol Nashville) gained three positions, moving back into the top 10 in its 37th week at No. 10 with 28,000 sold (up 11%). New albums by former White Stripes frontman Jack White, country singers Lee Brice and Kip Moore and another Brit boy band, the Wanted, are prime candidates for top debuts on next week’s chart.