GENETIC DIVERSITY ESTIMATION AMONG THIRTEEN LATE MATURING MANGO VARIETIES USING SSR MARKERS

Abstract

Genetic diversity estimation of 13 varieties of mango was assessed using 28 microsatellite markers. Mean values of 3.9231, 0.4455, 0.5407 and 0.4952 were observed for alleles, minor alleles frequency, gene diversity and polymorphic information content respectively. The observed heterozygosity value of YY implies that spontaneous hybridization may have contributed to the ancestry of some genotypes and that improvement by farmers may have possibly been by selection of somatic mutants. The dendrogram of the cluster analysis revealed three groups. Findings demonstrated the efficiency of SSR markers in distinguishing closely related mango varieties due to their high specificity. The study contributes to the understanding of the genetic organization of the mango germplasm. Nonetheless, fifteen SSR markers were used in thirteen exotic mango varieties to calculate polymorphism percentage, genetic diversity, frequency based genetic distances, genetic diversity percentage, allelic frequencies and PIC values. Polymorphism percentage recorded was 76.48%. Moreover, varietal similarity index of genome helped to construct phylogenetic tree that divided all varieties into three clusters according to their genetic similarities. First cluster that exhibited similarity in genetic consonance included varieties viz. Collector, Haden, Zill, Early gold and Pope. Two varieties i.e. Momi-k and Spring Fells were similar to each other genetically. Similarly, third cluster encapsulated Kensington Pride, Tomi-Atkin, Keitt, Maya and Sensation cultivars in genetic harmony.