Browsing by Author "Mmari, Doreen John"

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    Banana genetic diversity and diagnostic tools for major nematode species affecting banana in Tanzania
    (University of Dar es Salaam, 2019) Mmari, Doreen John
    Banana (Musa species EL]) is an important staple food and cash crop for about 30 percent of the total population in Tanzania. Plant parasitic nematodes (PPN), mainly the burrowing and root lesion nematodes are among the major constrains to banana production in Tanzania. The objectives of this study were to establish genetic diversity of banana grown in Tanzania, to identify major PPN affecting banana using morphological and molecular methods and to develop and validate simple and rapid molecular diagnostic tools for PPN. Genetic diversity and population structure of 159 banana varieties from four agro-ecological zones in Tanzania was evaluated using 20 simple sequence repeat (SSR) markers analyzed with the unweight pair group method with arithmetic means (UPGMA) method. The SSR markers revealed high genetic diversity among banana varieties grown in Tanzania and were able to separate banana varieties into two major clusters (cluster A and B) based on their similarities. Of these, 128 distinct genotypes were identified and 31 were overlapping genotypes. Identification of the root lesion and burrowing nematodes using morphological and molecular methods confirmed their presence in most of banana varieties grown in Tanzania. The PPN identified in this study were similar to other banana infesting PPN reported elsewhere in the world especially Europe and Asia. Furthermore, the rapid diagnostic tools designed from the ITS 1 & 2 and LSU D2, D3 expansion segment of rDNA of Pratylenchus spp. and Radopholus similis were able to distinguish these nematodes to species level. Information on genetic diversity and PPN infesting banana is crucial for developing banana varieties resistant to PPN. The simple and rapid molecular diagnostic tools developed in this study can be adopted for routinely screening of PPN infesting banana for sustainable nematode management in Tanzania and beyond.