Analysis of genetic diversity in mango (Mangifera indica L.) using isozymetic polymorphism

Abstract

The isozymetic study was designed for assessing the genetic diversity among the selected mango cultivars/genotype available in Bangladesh. All the isozymes, used in the present study showed polymorphism for mango. A total of 25 different electrophoretic zymotypes were observed for three isozymes studied. Glutamate oxaloacetate transaminase, malate dehydrogenase and peroxidase analysis possessed 8, 10 and 7 zymotypes, respectively, and genotypes were grouped into different electrophoretic zymotypes which indicated higher level of genetic diversity of mango. For glutamate oxaloacetate transminase, G₆ was the most common zymotypes whereas G₃, G₅, and G₈ were found in few cases. Similarly, M₈ and M₆ in malate dehydrogenase as well as P₆ and P₅ in peroxidase were found more frequent while other zymotypes in both isozymes were less frequent. Frequency was very few for one zymotype in all cases of three isozymes such as, G₈, M₁₀ and P₇. Cluster analysis through UPGMA dendogram using isozymes electrophoretic pattern provided strong information about existence of variability among the genotypes of mango. Based on Euclidean distance, a dendogram was constructed using banding pattern of 60 mango genotypes developed through three isozymes activities. The dendogram showed eight major clusters designated as I, II, III, IV, V, VI, VII and VIII. The results generated with isoenzyme will be helpful in improvement as well as may guide us in designing strategies that maximize the utility of genetic resources.

Key words: Polymorphism, isozyme, mango, genetic diversity, variety.