SSR marker assisted assessment of genetic diversity among mango (Mangifera indica L.) genotypes

Abstract

Mango (Mangifera indica L.) is one of the most economically important tropical fruit crops, valued for its nutritional quality, sensory attributes, and wide genetic variability. Assessment of genetic diversity among cultivated genotypes is essential for effective germplasm conservation and crop improvement. The present study was conducted to evaluate genetic diversity and relationships among 50 popular mango genotypes cultivated in Telangana, India, using simple sequence repeat (SSR) markers. A total of 60 SSR markers were screened, of which 42 produced clear and reproducible polymorphic amplification. These markers generated a total of 109 alleles. Allele size ranged from 100 bp (MiIIHR 06b) to 330 bp (MiIIHR 14b), with an average of 2.21 alleles per locus. Polymorphic information content (PIC) values ranged from 0.24 to 0.80, with a mean of 0.53, indicating moderate to high informativeness of the markers. Major allele frequency varied from 0.36 to 0.94, observed heterozygosity from 0.00 to 0.98, and gene diversity from 0.11 to 0.73, reflecting substantial genetic variation among the genotypes. Cluster analysis using Jaccard’s similarity coefficient and UPGMA grouped the genotypes into three major clusters at a similarity coefficient of 0.62. The results demonstrate the effectiveness of SSR markers in discriminating mango genotypes and provide a valuable basis for selecting diverse parental material for mango breeding and improvement programmes.