agrotecnologia

Abstrato

Evaluation of Genetic Diversity in Aerial Yam (Dioscorea bulbifera L) using Simple Sequence Repeats (SSR) Markers

Aniefiok Ndubuisi Osuagwu, Edem UL

Dioscorea bulbifera is an underutilised crop of the family Dioscoreacea widely distributed throughout the tropical and sub Saharan regions of West Africa. Twenty five D. bulbifera accessions from West Africa held in International Institute of Tropical Agriculture (IITA) germ plasm bank were screened for genetic diversity using ten microsatellite loci in 25 ul volume reaction in a 96 well micro titre plate PCR reactions. The reaction mixture consisted of 3 µl of 10 ng/µl template DNA, 2µl of 2.5 mM DNTPs, 1 µl of 2.5 mM MgCl₂, 1µ each of forward and reverse primers, 1 µl of DMSO₄, 0.1 µl of 5 µg/µl Taq DNA polymerase (Invitrogen) and 3 µl of 10 ng/µl DNA. The total reaction volume was made up to 25 volume using 13.4 µl nuclease free water. The PCR programme consisted of denaturation at 94°C for 30 secs, followed by 35 cycles of 94°C for 30s, 55 or 45°C for 20s and 72°C for 30 s, with a final extension step at 72°C for 7mins. A total of 74 alleles were detected with an average allele number of 7.4 per locus. A Polymorphic Information Content (PIC) mean value of 0.74 showed existence of variability among the accessions. A mean gene diversity value of 0.77 was also observed. SSR approach proved to be a valuable tool in the determination of genetic diversity and relationships among D. bulbifera accessions. These results are significant in the conservation and genetic improvement program of this crop.