Genetic Diversity of Ethiopian Groundnut (Arachis hypogaea L.) Accessions
Background: Groundnut (Arachis hypogaea L.) is the world’s most important source of edible oil and vegetable protein. Understanding its genetic diversity is important for the sustainable use and conservation of the crop. To our knowledge, little is known about the genetic variability of cultivated Ethiopian A. hypogaea.
Objective: To determine the genetic variability and diversity of 43 accessions of A. hypogaea collected from different regions of Ethiopia using ISSR markers.
Materials and Methods: Seeds of 43 A. hypogea accessions collected from different regions of Ethiopia by Ethiopian Biodiversity Institute were planted in plastic pots in a greenhouse of Melkasa Agricultural Research Center. Young fresh leaves from four weeks old plants were used to extract genomic DNA using CTAB (Cetyl trimethyl ammonium Bromide) method. Four reproducible ISSR primers were used for amplification and the amplified products were separated on 1.67% agarose gel. Percentage of polymorphic bands, polymorphic information content (PIC), the mean Nei’s gene diversity and Shannon’s information index were determined. NTSYS-pc version 2.02 software was used to calculate the Jaccard’s similarity coefficient for all possible pairs of samples.
Results: Out of 56 reproducible bands generated, 29 (51.8%) were polymorphic. The band size ranged from 120 bp to 1100 bp. The polymorphic information content (PIC) value ranged from 0.29 to 0.76 with the average value 0.49. The mean Nei’s gene diversity and Shannon’s information index were 0.25 and 0.33, respectively. Genetic relationship between A. hypogaea accessions based on Jaccard’s pair wise similarity coefficients varied from 44% to 83% with an average value of 63.5%. The UPGMA analysis grouped A. hypogaea accessions into five distinct clusters at 63.5% similarity coefficient, and the principal coordinate analysis revealed similar grouping.
Conclusions: ISSR marker-based analysis showed the presence of genetic variability among the accessions. UPGMA and PCoA clustered most of the accessions irrespective of their geographic origins. In addition, the current study demonstrated the informativeness of ISSR markers in estimating the extent of genetic variation among A. hypogaea accessions. This study is a milestone for future conservation and breeding program of the crop. We recommend further investigation with more geographic range and additional molecular markers to elucidate a clear genetic diversity of groundnut in Ethiopia.