Isozyme Pattern and Morpho-agronomical Traits Based Genetic Divergence Studies in Maize (Zea mays L.) Inbreds

The present investigation was carried out with an objective to study genetic divergence based on morpho-agronomical traits and isozyme pattern in eight maize inbreds. These inbreds were evaluated in randomized block design with three replication for ten morph-agronomical traits. Horizontal starch gel electrophoresis technique used to study the isozyme polymorphism in different tissues of eight inbreds. Analysis of variance revealed significant differences among the inbreds for all the ten morpho-agronomical traits. Nature and extent of genetic divergence for morpho-agronomical traits was measured using average taxonomic distances as a measure of dissimilarity coefficient. Eight inbreds were clustered into four groups (A, B, C, D) based on dissimilarity coefficient. Cluster B and cluster D showed the highest inter cluster distance (2.2422) and the lowest was observed between clusters B and C (1.0401). Cluster A exhibited the highest intra cluster distance (0.8519). Based on inter cluster distances inbreds present in cluster B and D were found more diverse consisted of inbred CML 186 and CM 600 respectively. Six isozyme systems were used for characterization and divergence studies based on similarity coefficients. Inbreds were classified into six clusters (A, B, C, D, E and F). The lowest (0.5957) similarity coefficient exist between inbreds CM 600 and CML 176 and the highest (0.8132) existed between inbreds CML 186 and CML 144. Cluster analysis in both cases reflected the moderate level of genetic divergence among the inbred lines but result may not be completely similar, but somewhat distinct and complementary in nature. Isozyme patterns was found to effective in revealing the nature of relationship among the inbred lines Therefore, divergence study using one estimate can’t replace the need to evaluate the relationship on the basis of the other which may be to used as parents in hybridization programme.