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SSR markers reveal
diversity in Guinea yam (Dioscorea cayenensis/D.
rotundata) core set
J. E. Obidiegwu1,2,3*, M. Kolesnikova-Allen4,
E. E. Ene-obong3, C. O. Muoneke3 and
R. Asiedu1
1International
Institute of Tropical Agriculture, Carolyn House, 26
Dingwall Road, Croydon CR9 3EE, UK.
2National Root Crops Research Institute, Umudike, P. M. B.
7006, Umuahia, Abia State, Nigeria.
3Department
of Agronomy, Michael Okpara University of Agriculture,
Umudike, Abia State, Nigeria.
4Biotechnology
Unit, Tun Abdul Razak Research Centre Brickendonbury
Hertford, UK SG13 8NL.
*Corresponding author.
E-mail:
ejikeobi@yahoo.com.
Tel.: +234-70-35029566.
Accepted 23
February, 2009 |
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The genetic diversity of 219 accessions of Guinea yam
germplasm from Benin, Congo, Côte d’ Ivoire, Equatorial
Guinea, Gabon, Ghana, Nigeria, Sierra Leone and Togo was
accessed using 15 microsatellite loci. High diversity of
0.677 was found among the accessions. An allelic average of
8.06 and polymorphic information content (PIC) value of 0.65
was observed for the markers. The observed heterozygosity
value of 0.563 suggests that spontaneous hybridization must
have contributed to the ancestry of some of the accessions
and improvement by farmers must have been far more often by
selection of somatic mutants. The twenty distinct cluster
groups generated by the radial phylogram shows that
Dioscorea cayenensis and D. rotundata are
distinct species with intermediate hybrid forms. There was
no relationship between relatedness of the accessions and
their geographical area of origin. This study contributes to
an increased understanding of the genetic organisation of
the core germplasm.
Key
words:
Core germplasm, Dioscorea cayenensis/D. rotundata,
genetic diversity, microsatellite. |
