2008 A P P L I E D A N D N A T U R A L S C I E N C E F O U N D A T I O N ANSF JANS Journal of Applied and Natural Science 9 (3): 1469 -1474 (2017) Estimation of genetic diversity among sugarcane ( Saccharum species com- plex) clones Rashmi Bisht, A. S. Jeena*, Deepak Koujalagi, S. P. Singh and K. A. Khan Department of Genetics and Plant Breeding, G. B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand), INDIA *Corresponding Author: dr.asjeena@gmail.com Received: November 11, 2016; Revised received: March 15, 2017; Accepted: July 25, 2017 Abstract: The experimental materials consisted of 36 sugarcane clones including two checks (Co Pant 97222 and Co Pant 3220). Analysis of variance revealed significant differences among all the clones for all the traits under study namely no. of millable canes, cane height, single cane weight, juice sucrose percent , purity percent , cane yield and CCS yield except cane thickness, juice brix and juice extraction percent. The divergence studies through Mahalanobis D 2 statistics grouped the 36 genotypes into eleven clusters. The maximum numbers of genotypes (21) were grouped in clusterI and the lowest(1)in cluster VI,VII,VIII,IX,X and XI. Members of cluster VII and XI (46.48) were found to be genetically most diverse on the basis of their inter cluster difference as opposite to clusters I and II (10.77) which are closely related. Cane height contributed maximum (15.397%) towards genetic divergence followed by Single cane weight (14.762%) and no. of millable cane (13.016%). These characters were considered to be most important for the genetic diversity. Lowest contribution was made by juice purity percent (4.286%) followed by Cane thickness(7.301%),Juice extraction percent (7.619%). Genetic diversity is important for sustainable production since greater losses of characteristics in any population limits its chances of survival. Little to no genetic diversity makes crops extremely susceptible to widespread biotic and abiotic stresses. Genetic diversity can be assessed by Mahalanobis D 2 statistic, which is a morphometric method and a powerful tool in quantifying the degree of divergence at genotypic level. Keywords: Characterization, Clusters, Diversity, D 2 statistics INTRODUCTION Sugarcane (Saccharum spp. complex) is an important industrial crop of tropical and subtropical regions of the world and is cultivated in about 100 countries around the globe for its high concentrations of sugar and recently for the production of ethanol as a source of bio-fuel (Andreoli and De Souza 2007). Sugarcane has recently highlighted as a source of sustainable en- ergy for the cogeneration of electricity and cellulosic ethanol from bagasse (Hofsetz and Silva, 2012). The by- products of the sugar industry are bagasse, molas- ses, filter-cake, wax etc. (Kang et al., 2013). The per- centage of sucrose varies from 12-18% depending of the variety of cane, its maturity, condition of soil, cli- mate and agricultural practices followed by the grow- ers (Singh and Singh 2002). The genus Saccharum, established by Linnaeus in 1793, belongs to family Poacae, subfamily Panicoideae, tribe Andropogoneae, subtribe Saccharineae and genus Saccharum (Watson et al., 1985). There are five species of this genus.Three among these are cultivated species namely S. officinarum originated in New Guinea / Indo-Burma- China border. S. barberi originated from North India. S. sinense originated from China. The two wild species ISSN : 0974-9411 (Print), 2231-5209 (Online) All Rights Reserved © Applied and Natural Science Foundation www.jans.ansfoundation.org are S. spontaneum originated from India and and S. robustum originated from New Guinea.Considerable difficulties have been faced in the improvement of sugarcane through hybridization due to narrow base of variation available. In sugarcane crop improvement is impeded by its narrow gene pool, complex genome, and poor fertility, caused by genetic recombination as well as long breeding selection cycle. The success of sugarcane breeding program therefore lies in the proper choice of rich and genetically diverse parents.The genetically diverse parents may be selected on the basis of diverse geographical distribution of the genotypes, information on agronomic characters (Melchinger, 1998). Normally in sugarcane breeding programs, the parental lines are selected on the basis of agronomic characters and pedigree records, bi-parental crosses and polycrosses between elite genotypes are used. The lack of genealogy data and the improper identification of some genotypes may impair estimation of the genetic diversity among sugarcane accessions. In addition, the continuous selection for the same traits such as sucrose content in breeding programs has lead to a reduction in genetic diversity, limiting further success in sugarcane breeding (Creste et al., 2010).