Genetic Relationship and Clustering of Some Sugarcane Genotypes Based on Esterase, Peroxidase and Amylase Isozyme Polymorphism

Three isozyme systems viz.esterase, peroxidase and amylase were assayed electrophoretically from extracts of leaf tissues of some elite genotypes of India to unravel their genetic relationship.Twenty five isozyme phenotypes were resolved in the 9 genotypes; 8 in esterase (EST), 12 in peroxidase (POX) and 5 in amylase (AMY).The genotypes could be distinguished on the basis of polymorphic isozyme spectra and multimeric isozyme profiles.The most polymorphic isoenzyme system was peroxidase (POX), which provided a discriminatory tool for evaluating and characterizing genotypes.The banding similarly index based on the number of polymorphic bands common between each genotype pair, ranged from 0.38 to 0.89.The genotypes were clustered in 2 distinct groups having 3 and 6 genotypes each by subjecting the genetic dissimilarity between them to UPGMA (Unweighted Pair Group Mean Analysis) statistical treatment and bootstrap analysis.The consistency Index of 8 different nodes present in phenogram representing percentage useable isozyme loci per node showed the node 8 to be the most important and consistent node followed by the node 6.Some esterase and peroxidase isozyme phenotypes were specific to the genotypes and were found to be suitable for cultivar identification.