GENETIC STRUCTURE AND GEOGRAPHICAL RELATIONSHIP OF SELECTED COLOCASIA ESCULENTA [L. SCHOTT] GERMPLASM USING SSRS

Abstract

Aims: SSR markers were used to infer population genetic structure variability in taro cultivars with the objective of characterizing the allelic diversity of each geographical population. Place and Duration of Study: Masinde Muliro University of Science and Technology and Beca Hub, ILRI, Nairobi. Methodology: Six highly polymorphic SSR markers widely distributed in taro population genome were used in genotype 50 cultivars collected from Kenya and a taro genebank (SPC Tarogen). Results: The average polymorphic loci was 87.88%. The highest Shannon information index was observed in the germplasm from Nyanza (1.04), Western (1.2) and Hawaii (1.11) and Malaysia (1.36). Only Malaysia and Thailand germplasm had allele unique to a single locus. The analysis ofmolecular variance (AMOVA) revealed that 70% of the variations found within individual taro accessions, 6% of variations among the taro populations and only 24% amongst individual taro genotypes and they were statistically significant (p<0.001). Principal component analysis clustered the taro germplam into different groups. In total 50.06% and 51.82% of the variation was explained by the first three principal components of the taro germplasm. Some of the Kenyan taro cultivars clustered together with the Tarogen germplasm. Conclusion: The determination of genetic diversity is core function towards understanding taro genetic resources for varietal identification to rationalize its collection and safeguarding the existing genetic diversity for taro germplasm conservation, management and for potential utilization for food security.