Estimation of genetic diversity of the Kenyan yam (Dioscorea spp.) using microsatellite markers

Abstract

Yam landraces in Kenya have not been fully characterized both at morphological and molecular level. Application of molecular markers can overcome this bottleneck. 187 accessions comprising of 166 yam landraces and 21 Yam DNA samples from IITA, Nigeria were extracted from leaf samples grown at Muguga and genotyped at BeCA. DNA was extracted using CTAB method. Twelve (12) primer pairs were used for genotyping and PCR products detected on ABI-3730 capillary system. Data was analyzed for genetic diversity, ordination and analysis of molecular variance with GenAIEx software. A total of 131 alleles were amplified with a minimum of two alleles and a maximum of 13 alleles per primer with a minimum allele size of 64 bp and a maximum of 368 bp. Accessions from Eastern province had the highest number of unique alleles. Shannon’s information index (I) was 0.1444 for West African samples and 0.2366 for Central province. Accession dispersion revealed four clusters with no distinct geographical pattern. Dense clustering of accessions was an indication of genetic relatedness. Analysis of molecular variance revealed that most variation of 88% (P<0.010) was found within populations or provinces. The simple sequence repeats (SSR) markers were polymorphic and were able to discriminate local yam landraces.