Sugar Cane is a Vanilla plant that can be found on grass, dirt, and Sand as long as it is adjacent to Water on at least one side (Not including top and bottom). Sugar Cane may grow to a maximum height of three blocks, but is occasionally found in new world generation up to seven blocks tall. The player can place sugar cane on a block or on existing sugar cane blocks to make sugar cane of any height. In Tekkit, Sugar Cane is primarily used to craft Paper, Plantballs, and Blowguns. It is also used to make Sugar, a Vanilla item that is also used in some Tekkit recipes. Sugar Cane may also be used in making Rum. Paper is used to make books, which makes them essential for enchanters and upgrading an enchanting table.
In Cross Breeding Sugar Canes are essential since they're the basis for a great many of other plants. Cross breeding them with each other and other plants can give you Wheat, Flowers, Melon, Pumpkins, Stickreed, Cocoa, more Sugar Cane and many other things.