Exploration of diversity and distribution of cytotypes of Saccharum spontaneum, a wild species of sugarcane, in India

Abstract

The present investigation was undertaken to examine the geographic distributions of cytotypes of Saccharum spontaneum L., wild species of sugarcane, in India. New chromosome determinations has been done for 524 accessions collected mainly from four ecological zones, West, East, North and North-east, of the country. A detailed evaluation of cytogeographic pattern of S. spontaneum has been done with these clones along with the clones in which chromosome data is already available. Twenty six cytotypes ranging from 2n=40 (8x) to 2n=112 (14X) has been identified in S. spontaneum from India. Gangetic valley of Sub Himalayan region and deltaic region of South-east zone can be considered as regions of cytogeographic interest with largest concentration of different chromosome numbers. North-east region of the country appears to have had a higher evolutionary activity in this species which is evidenced by the occurrence of multiple cytotypes and sympatric growth with other species and genera. The overall cytogeographic pattern of S. spontaneum includes the incidence of mixed polyploidy, aneuploidy, sympatric with different ploidy levels and disjunct distribution of some cytotypes indicate that this species likely to have had multiple independent origin in different parts of India