Sugarcane is a large perennial grass cultivated mainly for sugar in more than 100 countries located between 35N and 35S of the equator. Till early part of 1900, Saccharum officinarum, the noble cane was under cultivation in almost all the countries. This species has the genes for very important traits like high sucrose content, high juice purity, thick canes, low fibre content, early maturity, self-stripping/detrashing and high tonnage (Daniels and Roach 1987). But susceptibility to major pest and diseases and poor ratooning prompted plant breeders to hybridize it with its wild relative, Saccharum spontaneum. Interspecific hybrids between S. officinarum and S. spontaneum were repeatedly backcrossed to S. officinarum a process called nobilization to recover clones with increased sugar and cane yield. But from latter part of 1930 onwards nobilization was seldom used and nobilized canes were used as parents in the genetic improvement. Currently, commercial varieties and clones in advanced stages are the main breeding parental stocks for development of sugarcane varieties. Almost all sugarcane cultivars currently under cultivation in the world are derived from a few common ancestral clones and therefore share a limited genetic bas