Abstract:
Brassica carinata (2n = 34, BBCC) is an amphidiploid plant arisen as a result of interspecific
cross between Brassica nigra (2n = 16) and Brassica oleracea (2n = 18). It is economically
important plant being cultivated for use as vegetable and oilseed. Though B. carinata is among
important oil crops, study on its genetic variability is lacking and this study is meant to
examine the genetic diversity and relationships of B. carinata accessions collected from
selected B. carinata growing areas of Ethiopia. Six ISSR markers were used to analyze the
genetic diversity and relationships of 60 accessions of B. carinata collected from four
geographical areas; Wello, West Shewa, East Wellega and Illu Ababora and assigned to four
populations according to the collection areas. A total of 73 bands were generated with an
average of 12.17 bands per primer. The percentage polymorphism observed in the populations
ranged from 65.75% to 84.93%. Nei’s gene diversity (0.34) was highest in accessions
collected from Illu Ababora and least (0.26) in accessions collected from Wello. The
proportion of the total genetic variation contributed by among population variation (GST) was
0.227 while 77.3% of the total genetic diversity was attributed to the within population
variation. AMOVA analysis revealed higher (75%) genetic variation within the populations
and less (25%) genetic variations among the populations. Clustering analysis and dendrogram constructed with UPGMA method resulted in similar clustering pattern. The
patterns of clustering in 2D and 3D scatter plots were supportive of the clustering pattern
obtained with UPGMA. The result in this study showed that ISSR Markers disclosed high level
of genetic diversity. Although ISSR markers enabled detection of high genetic diversity in the
60 accessions used in this study, more analysis should be done with more number of
accessions collected from vast geographical areas.
