EVALUATION OF POLYMORPHISM GENERATED BY SINGLE SEQUENCE REPEAT MARKERS IN SELECTED TARO POPULATIONS

Abstract

Fifty cultivars were evaluated using six SSR primer combinations. Significant polymorphic variations within the Kenyan and Tarogen taro sub-populations were revealed. A total of 64 alleles were detected with sizes from 99 to 294 bp. Kenyan germplasm generated 30 alleles and averaged 5.0 alleles/ locus while the Tarogen revealed 34 alleles with an average of 5.70 alleles/ locus. Primers generated a higher polymorphism information content (PIC) in Tarogen (0.6508) compared to Kenyan (0.6108) genotypes and genetic diversity index mean in Tarogen (0.6989) than Kenyan (0.6530) genotypes. Genetic diversity ranged between 0.25 to 0.6218 and 0.25 to 0.06204 for Kenyan and Tarogen genotypes. Allele frequency ranged from 42.52 to 75% across the populations. Generally, observed mean heterozygosity was lower than the expected mean genetic diversity indexes of 0.6530 and 0.6989 for Kenyan and Tarogen. Kenya recorded the highest mean genetic diversity (0.4735) and richness (3.04), allele frequency (0.62) and PIC (0.412) while Tarogen recorded 2.0, 0.4527, 0.5988 and 0.3917, respectively. Observed genetic diversity was significantly greater than the expected diversity. All the evaluated primers displayed distinct polymorphisms among the taro accessions studied indicating the robust nature of microsatellites in revealing polymorphism variability.