The immediate ancestor of rock "n" roll is rhythm -and-blues.

摇滚乐直接源自节奏布鲁斯。

youdao

At this time, early "rockers" were mixing the country music of white America with the rhythm and blues sound loved by the black us citizens. The result was rock 'n' roll.

当时，早期的“摇滚青年”将美国白人的乡村音乐和美国市井黑人热爱的节奏和蓝调音乐结合起来，结果就形成了摇滚乐。

youdao

It doesn't matter if it's traditional jazz, blues or rock 'n' roll.

FORBES: Magazine Article

He went through changes that ranged from imitating Nat Cole and Charles Brown to finding his own voice in jazz, gospel, rhythm and blues, rock 'n' roll, country, pop and soul.

WSJ: A Performance With Soul

The building was once Chess Records, the seminal electric blues label that paved the way for rock 'n' roll.

BBC: Chicago's jazz and blues shrines