Genetic diversity assessment in Somali sorghum (Sorghum bicolor (L.) Moench) accessions using microsatellite markers

Abstract

In the north-western region of Somalia, bordering Ethiopia, sorghum represents an important resources for human and animal nutrition. The critical situation of Somalia is threatening the preservation of this valuable resource and it becomes urgent to develop a strategy of correct evaluation of the sorghum germplasm in order to promote conservation and preservation programs. Microsatellites, also known as Simple Sequence Repeats (SSRs), are reproducible molecular markers useful in assessing the level of genetic diversity of plants. A total of 5 sorghum SSR-specific primer pairs were used to assess the genetic diversity of Somali sorghum landraces. Extensive variation was found at the microsatellite loci analysed, except for a locus that resulted in a monomorphic for some accessions. Considerable differences were found between total and effective number of alleles indicating non uniform allele frequency. Moreover allele frequency at a single locus significantly changed among accessions. Total gene diversity calculated for each locus ranged from 0.44 to 0.79. Most of the genetic diversity occurred within accessions demonstrating that accessions are not under selection processes and/or there is a continuous exchange of genes between sorghum populations. In any case, the patterns of clustering were significantly affected by the presence/absence of some alleles with high discriminant weight. Accessions Carabi, Abaadiro, Masego Cas and Masego Cad represent distinct genotypes confirming finding observed in previous phenotypic studies. The results highlight the central role of local farmers in maintaining and shaping local germplasm.

Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) accessions using single nucleotide polymorphism markers

“…These results negate those of Manzelli et al . (2007) and Motlhaodi et al . (2014) who reported higher variation among accessions than within accessions but was similar to those of Tadesse and Feyissa (2013) and Tesfamichael et al .…”

Genetic variation in lowland sorghum (Sorghum bicolor(L.) Moench) landraces assessed by simple sequence repeats

“…The high level of gene flow observed among the landraces may be attributed to the fact that farmers in Ethiopia maintained large numbers of varieties on a single plot, based on a range of selection criteria, in order to cope with diverse environmental stresses (Teshome et al , 2007). This may result in a continuous exchange of genes through pollen flow (Manzelli et al , 2007). In addition, the low genetic differentiation observed among the population can be caused by either the frequent occurrence of gene flow or a low genetic drift due to a high effective population size (Dje et al , 1999).…”

“…Similarly, Deu et al (2010) pointed out the significant role contributed by farmers in the management and preservation of genetic diversity over time. The high genetic variability observed among landraces provides enough genetic plasticity for the crop to adapt to diverse environmental conditions in tropical areas (Manzelli et al , 2007), and allow them to circumvent crop failure by reducing vulnerability to environmental stresses. The study of genetic diversity among sorghum landraces could serve as an important source of valuable alleles for drought tolerance in future sorghum improvement programmes.…”

“…DNA-based molecular markers are more reliable and robust methods for the characterization of genetic diversity. A range of molecular markers have been used on sorghum to determine its genetic diversity, including restriction fragment length polymorphism (Perumal et al , 2007), amplified fragment length polymorphism (AFLP; Ayana et al , 2000), simple sequence repeats (SSRs; Manzelli et al, 2007; Ganapathy et al , 2012), single nucleotide polymorphisms (Morris et al , 2013) and diversity array technology markers (Bouchet et al , 2012).…”

Genetic Diversity of Maize Accessions (<i>Zea mays</i> L.) Cultivated from Benin Using Microsatellites Markers

“…Widely used in the construction of the genetic map of the human genome, the SSR markers were used in the mapping of the plant genome [16]. Thus, in many plants, microsatellites are known to be more effective in genetic characterization and better indicated for structuring of genetic diversity studies [17] [18]. So, considering their interest in genetics, they are known to be neutral markers, co-dominant, extremely polymorphic and distributed throughout the genome [19].…”