3. Results and discussion

#### 3.1. Results

#### 3.1.1. Molecular/genetic relatedness among accessions

The coefficient of dissimilarity varied from 0.28 to 0.66, being <1 or 100% showing no duplication among accessions from the 21 loci covering 11 linkage groups used as shown in Figure 1. Hence, the eight accessions belonging to AA-Mshale group were found to be genetically different. The dendrogram (Figure 1) established two main clusters (A and B). In the first cluster (A), AAA-Lujugira-Mutika accessions ('Bukoba'/Musakala, 'Muhowe'/Beer (Mbidde) and 'Embwailuma'/ Nakitembe) were clustered with the seven accessions ofAA-Mshale ('Ndyali', 'Mshale makyughu', 'Ilalyi', 'Mshale malembo', 'Nshonwa mshale', 'Ijihu' and 'Huti'). They included the tie of AAAA-FHIA (17 and 23) accessions with 'Yangambi km 5' (AAA-Ibota), 'Mzungu mwekundu' (AAA-Green-red) and 'Green bell' (AAA-Cavendish). Whereas in the second cluster (B), six heterogenomic accessions named 'Kisukari' (AAB-Silk), 'Ngego I', 'Ngego Halisi' and 'Mzuzu' (AAB-French Plantain), 'Unyoya' and 'Bokoboko' (ABB) were tied to three homogenomic accessions (AAA) 'Jamaica' (Gros Michel), 'Kimalindi fupi' (Dwarf-Cavendish) and Mwanjunjila (EAHB having a yellow male bud). The accession 'King banana' (AA) was an outline.

The genetic variation causes were allelic deletion or non-annealing and heterozygosis. The mMaCIR168 primer showed allele deletion in cultivars 'Ndyali' and 'Mwanjunjila' (first one and third three after (left) Ladder, Figure 2), and mMaCIR189 showed heterozygosis in cultivars 'Mshale Makyughu', 'Ilalyi' and 'King banana' (first six, nine and second three after ladder) while both primers showed a homozygote allele in cultivar 'Mshale malembo' (the first number six after the ladder). Similarly, alleles' deletion (null alleles) was observed among 19 cultivars for primers mMaCIR117 and mMaCIR174. The alleles' sizes resemble those of Hippolyte et al. [13].

The observed mutation has negatively influenced the principal component analysis (PCA) that resulted in poor fit of the clustering analyses with a cophenetic coefficient of 0.72 from distance matrix and 0.67 from product-moment correlation matrix. Consequently, the variation has spread over the principal component (PC) so that the three first PCs cannot hold the maximum of the variation (Figure 3) and hence weakened the value of PIC (Polymorphism Information Content).

Genetic Diversity in Banana and Plantains Cultivars from Eastern DRC and Tanzania Using SSR and Morphological… 65 http://dx.doi.org/10.5772/intechopen.79922

Figure 1. Phenogram from UPGMA clustering of the average Manhattan coefficients between the 25 Musa accessions using 21 microsatellite markers covering 11 linkage groups.

#### 3.1.2. Cladistic relationship

The cladogram showed three clades which revealed mono-, para- and polyphyly (A, B and C, Figure 4). The eight AA-Mshale accessions were subdivided into two clades. The first clade (A) was a monophyletic group composed of eight accessions in which six belonged to AA-Mshale genomic group ('Ndyali', 'Mshale malembo', 'Ijihu', 'Nshonwa mshale', 'Huti' and 'King banana') and two of triploid ('Green bell' (AAA-Cavendish) and 'Mzungu mwekundu' (AAA-Green-red).

Figure 2. On gel image of alleles from mMaCIR117, mMaCIR168, mMaCIR174 and mMaCIR189 using 25 banana accessions (eight edibles diploids (AA-Mshale), nine AAA, two AAAA, four AAB and two ABB genomic groups) of (SUA) (Tanzania).

The second clade (B, Figure 4) that encompassed AAA-EAHB accessions was subdivided into two subclades (B1 and B2) and formed paraphyletic group with the first clade. The first subclade (B1) was made of three accessions, 'Mzuzu', 'Bukoba' and 'Yangambi km 5', that belonged to AAB-French Plantain, AAA-EAHB-Musakala and AAA-Ibota, respectively. Whereas, in the second subclade (B2), the AAA-EAHB accessions 'Muhowe' and 'Embwailuma' shared the ancestry with AA-Mshale (Mshale makyughu and Ilalyi) and AAAA-FHIA (17 and 23). The last clade (C) had 'Kimalindi fupi' (AAA-Cavendish), 'Mwanjunjila' (AAA-EAHB) and Jamaica (AAA-Gros Michel) sharing a common ancestry with AAB-Silk (Kisukari), AAB-French plantain (Ngego Halisi and Ngego I) and ABB (Bokoboko and Unyoya). The clade (C) established a polyphyly with the two first clade (A and B) that had AA genomic group accessions. Whereas, in reference to accession 'Jamaica', there was a paraphyly between the clades B and C.

#### 3.2. Discussion

This clustering from dissimilarity using UPGMA fairly confirms the relationship established by numerical taxonomy between the AA-Mshale malembo and the AAA-Lujugira-Mutika group determined by several authors [2, 7–9]. Likewise, the observed alleles' differences among AA-Mshale accessions were in line with the morpho-taxonomic dissimilarity determined previously by the upcited authors. Moreover, the clone sets (Musakala, Nfuuka and Nakitembe) coined Genetic Diversity in Banana and Plantains Cultivars from Eastern DRC and Tanzania Using SSR and Morphological… 67 http://dx.doi.org/10.5772/intechopen.79922

Figure 3. PCA showing the relative positions on the first (Dim-1) and second (Dim-2) PCs of the 25 banana accessions of the SUA's genebank using 21 microsatellite primers.

subjectively within the AAA-Lujugira-Mutika were linked with the different AA-Mshale accessions following their alleles' closeness [16]. Interestingly, the clustering of AAA-Cavendish, AAA-Gros-Michel, AAA-Ibota, AAB-Plantain and AAB-Silk subgroups as sympatric is similar to results of [11, 12, 17], while they used other techniques or primers partly covering the 11 linkage groups [13]. This once more established the usefulness and reliability of the alleles from the 11 linkage groups in diversity and cladistic study.

Figure 4. Cladogram from neighbor joining clustering of the Manhattan dissimilarity coefficients between the 25 Musa accessions from SUA genebank and 21 microsatellites.

The mono-, para- and polyphyletic relationships are in line with those revealed from numerical morpho-taxonomy [7–10]. The para- and polyphyletic relationship may be explained by the hypothesis of back-crosses developed [2]. The back-crosses theory explains the role of the observed alleles deletion and rearrangement (heterozygosis) in the evolution of AA-Mshale malembo in the AAA-EAHB. These relationships were also similarto results from other microsatellites covering 10 linkage groups [17]. However, there is contrast with the statement of lack of convincing lineage between 'Mutika-Lujugira', 'Red', 'Ibota' and 'Plantain' subgroups, and the diploid M. acuminata accessions. This may be explained by the poor fit of the clustering analysis and the spread of principal components over the variables due to observed mutation.
