Genetic diversity analysis of cucumber (Cucumis sativus L.) genotypes based on ISSR markers

Abstract

Molecular characterization and genetic diversity among fourteen cucumber genotypes were carried out by using eleven Inter Simple Sequence Repeat (ISSR) markers. All the eleven ISSR markers used were found polymorphic having 97.72% polymorphism among fourteen cucumber genotypes comprising pathenocarpic, gynoecious and monoecious cucumbers. These eleven polymorphic markers produced a total of 69 alleles, of which 4 were unique alleles. The allele number for each ISSR locus varied between 4 to 10 with an average of 6.27 alleles per marker. Polymorphic information content values of ISSRs ranged from 0.43 to 0.84 with an average of 0.68. Jaccard’s similarity coefficient was employed to study the molecular diversity of 14 cucumber genotypes. The pair wise genetic similarity among 14 cucumber genotypes varied from 0.36 to 0.83. The dendrogram constructed based on genetic similarities among 14 cucumber genotypes identified two major clusters. The four major parthenocarpic genotypes viz., PCUCP-2, PCUCP-4, PCUCP-6 and PCUCP-8 having high genetic resemblance (80-83%) and two major gynoecious genotypes viz., PGYC-3 and PGYC-2 with 68% similarity value were grouped in a single cluster and three monoecious genotypes viz., PCUC-8, PCUC-25 and Pant Khira-1 were grouped in another cluster with 76-78% similarity value. This study provides information about diversity among pathenocarpic, gynoecious and monoecious cucumber genotypes and remains helpful in future exploration and utilization of diverse germplasm for developing cultivars and hybrids.