Early Indian Rig Vedic hymns were tri-tonic, sung in three pitches with no octave: Udatta, Anudatta, and Swarita.
Maori
In a 1969 study, Mervyn McLean noted that tritonic scales were the most common among the Maori tribes he surveyed, comprising 47% of the scales used.[3]
South America
The pre-Hispanic herranza ritual music of the Andes is generally tritonic, based on a major triad, and played on the waqra phuku trumpet, violin, and singer with a tinya drum. The tritonic scale is largely limited to this ritual and to some southern Peruvian Carnival music.[4]
^Bruno Nettl and Helen Myers (1976). Folk Music in the United States: An Introduction, third edition (Wayne Books WB41) Detroit: Wayne State University Press, p. 40. ISBN9780814315569 (cloth); ISBN9780814315576 (pbk).