IN SONG AND DANCE ALONG THE SILK ROUTE
''DURING the 5,000 years of our history, dance has never been separated from life: you take the tail of the ox and you dance with it. And each of China's 56 nationalities has many distinctive forms of dance. Dance in China is like a flower nursery, with a hundred different flowers blossoming through time.'' The speaker was Hu Zhihou, a member of the troupe from China that will perform on Sunday in ''Music and Dance of the Silk Route,'' an unusual program of Asian folk music and dance, in the Asia Society's Lila Acheson Wallace Auditorium. The troupe, sponsored by the society in cooperation with the Chinese People's Association for Friendship With Foreign Countries, will perform at the society's auditorium through Wednesday. Mr. Hu is a noted player of the guanzi, a bamboo reed pipe that dates back more than a thousand years. Now one of China's most popular instruments, the guanzi was introduced to the Xinjiang region of China by Persian merchants traveling the silk route through Central Asia, a major commercial route established toward the end of the second century B.C., and used most heavily in the fifth and sixth centuries of our era.