Investigation for diversity in parental stocks of sugarcane (Saccharum spp)

Abstract

The present investigation aimed to assess the nature and magnitude of genetic divergence available in the hybridization block of ICAR-Sugarcane Breeding Institute, Coimbatore and to select suitable diverse genotypes as parents for further utilization. Seventy one sugarcane parental genotypes comprising Coimbatore canes (Co canes), Co allied canes and exotic parents were explored for their genetic diversity. Fifteen traits viz., HR Brix (330 days), Brix %, Sucrose % days, Purity %, commercial cane sugar (CCS) %, cane length, cane diameter, single cane weight, number of millable canes (NMC), number of internodes, internode length, estimated cane yield and estimated commercial cane sugar yield at 300 days and brix and sucrose % at 240 days were recorded during two crop seasons (2015 and 2017). Data was subjected to cluster analysis using Mini tab software. Based on the cluster analysis, two major groups were identified which were classified into nine clusters. The cluster wise mean values indicated substantial variation among the clusters. Maximum mean value for NMC was in cluster V. Cluster IV was found to be the largest with 21 genotypes followed by cluster I with 14 genotypes and cluster II with 12 genotypes. Cluster VI had nine genotypes and Clusters VII and VIII had three genotypes each. Clusters V and IX were the smallest with a single genotype. Cluster V was most distinct cluster among the derived clusters and it showed maximum distance with clusters I, II, III, IV and IX. Other distinct cluster in this group is cluster IX and showed the maximum inter cluster distance with clusters VI, VII and VIII. Among the distinct clusters, the cluster III expressed superior performance for most of juice quality traits at 300 days while clusters I, II and cluster III showed their superiority for sucrose content at 240 days. Clusters III, IV and VI exhibited superiority for cane yield. The most divergent clusters observed were Clusters III and VI and III and VII. Minimum inter cluster distance was found between Clusters I and II. Genotypes with high inter- cluster distance can be exploited to produce more genetic variability and desirable recombinants for further improvement