DIVERSITY PROFILING OF INDIAN-ORIGIN SACCHARUM OFFICINARUM CLONES THROUGH MOLECULAR CHARACTERIZATION

Abstract

Saccharum officinarum, commonly known as noble cane, contributes approximately 80–90% of the genome of modern nobilized sugarcane cultivars and is an important source of high sucrose content and superior juice quality. However, the genetic diversity present in Indian-origin S. officinarum germplasm has received limited molecular characterization. In the present study, 24 elite Indian-origin S. officinarum accessions conserved at the ICAR-Sugarcane Breeding Institute Research Centre, Kannur, were genotyped using twenty simple sequence repeat (SSR) markers to assess genetic diversity, clustering patterns, and population structure. A total of 241 alleles were amplified, with an average of 12.05 alleles per marker and an overall polymorphism of 98.76%. The mean polymorphic information content values ranged from 0.209 to 0.467. Analysis of Molecular Variance showed that 83.5% of the total molecular variation was distributed within clusters, while significant differentiation was observed among clusters (PhiPT = 0.165, P = 0.0001). Jaccard's dissimilarity coefficients ranged from 0.3273 to 0.8162, with a mean of 0.6156 ± 0.0866, indicating that all 24 accessions retained a distinct molecular identity. UPGMA clustering grouped the accessions into four clusters, with a single cluster comprising 79.17% of the germplasm. This clustering pattern was broadly supported by Principal Coordinate Analysis. Overall, the findings suggest that although the collection is genetically cohesive, possibly reflecting a historically narrow breeding base, each accession remains molecularly distinguishable. The SSR panel used in this study therefore provides a useful tool for germplasm curation and for identifying genetically distinct clones for future sugarcane breeding programmes.