Assessment of genetic divergence using Mahalanobis D2 analysis in mango

Different genotypes are to be classified into clusters based on genetic diversity for any plant improvement programme. Further the extent of genetic divergence between them needs to be estimated. D2 statistics is one of the powerful tools to assess the relative contribution of different component traits to the total diversity, to quantify the degree of divergence and to choose genetically diverse parents for obtaining desirable recombinants. The present study was conducted at Horticultural College and Research Institute (Tamil Nadu Agricultural University), Periyakulam during 2017-18 on 27 genotypes of mango for genetic divergence with respect to forty six yield contributing traits. The analysis of variance exhibited significant differences among genotypes for all the forty six characters studied. Twenty seven genotypes were grouped into six clusters. The cluster size varied from single genotype (cluster III and VI) to thirteen genotypes (cluster I). Cluster II and IV had three genotypes each. Cluster V consisting of six genotypes. No relationship between geographic and genetic diversity was revealed as genotypes from same geographic area fell in different clusters and vice versa. The intercluster distances were more than intracluster distances. The highest intercluster distance was observed between cluster II and III followed by clusters II and IV. The other intercluster distances were of low magnitude. Hence crossing between genotypes of cluster II with those from cluster III and IV will be rewarding. Based on intercluster distances and cluster mean for different characters, parents were identified which upon crossing may yield desirable recombinants