Crop Science and Production Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/37

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Browsing Crop Science and Production Collection by Subject "Banana"

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    Banana xanthomonas wilt: occurrence and means of transmission in Kagera, Mwanza and Mara regions of Tanzania
    (2016-02) Hashim, Ibrahim; Mabagala, Robert B
    Abstract: Banana Xanthomonas wilt (BXW) disease is a major constraint of banana production in the Lake zone (Kagera, Mwanza and Mara) regions of Tanzania where banana plays an important role as a staple food and cash crop. Infected plants die and fruits rendered inedible. To assess the current status of BXW disease field surveys were conducted from December, 2011 to January, 2012 in Kagera, Mwanza and Mara regions. Twenty eighty banana samples with BXW disease symptoms were randomly collected from a total of 147 surveyed fields. Farmers’ knowledge of BXW disease was assessed using a checklist, discussions and direct field observations. Isolation of bacteria was done on Yeast Peptone Glucose Agar and identification was done based on morphological, biochemical and pathogenicity test. Results indicated that the incidence of BXW disease was highest (56.7 %) at Ihangiro and the lowest (10 %) at Ruhija and Mulela, in Muleba District; Nakamwa and Busagami, in Ukerewe District. Such results implied that, BXW disease is still a constraint to banana production in the surveyed districts. The results also indicated that BXW pathogen transmission was through infected farming tools (65.4 %) in Muleba District and infected planting materials in Tarime (50.5 %) and Ukerewe (45.8 %) Districts implying that these were the major means by which BXW disease was spread in the study area. About 58.33 % and 41.67 % of the farmers in Ibare and Kishanda villages, respectively, in Muleba District associated pied crow (Corvus albus L.) with the transmission of BXW causing pathogen. Results based on morphological, biochemical and pathogenicity test indicated that, four out of 16 bacteria isolated from infected banana samples were Xanthomonas campestris pv. musacearum (Xcm). Further studies on the relationship between the pied crow and Xcm transmission in Kagera, Mara and Mwanza regions, are recommended.
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    Identification and management of microbial contaminants of banana in vitro cultures
    (Journal of Applied Biosciences, 2012) Msogoya, T. J.; Kanyagha, H.; Mutigitu, J.; Kulebelwa, M.; Mamiro, D.
    Microbial contamination is one of the major challenges hampering the application of in vitro micropropagation technique for mass production of pest-free banana planting materials at the Sokoine University of Agriculture in Tanzania. Objectives: The objectives of this study were to identify bacterial and fungal contaminants of banana in vitro cultures and to test the efficacy of selected antibiotics and antifungal agents in the elimination of such contaminants. Methodology and results: Purified bacterial isolates were identified based on vegetative cell shape, gram reaction, fluorescent pigment and standard biochemical tests. On the other hand, pure fungal isolates were microscopically identified based on structural and morphological characters. Four antibiotics, namely rifampicin, gentamicin, chloramphenicol and vancomycin each at 100, 150 and 200mg /litre and three antifungal agents, namely ketoconazole, fluconazole and nystatin each at 100, 150 and 200 mg/litre were used in the culture susceptibility tests of the identified bacteria and fungi, respectively. The bacterial contaminants of banana in vitro cultures were Proteus spp., Erwinia spp., Klebsiella spp. and Staphylococcus spp. while the fungal contaminants were Aspergillus spp., Fusarium spp,. Penicillium spp. and Candida spp. Culture susceptibility tests revealed that gentamicin, rifampicin and chloramphenicol each at 150mg/litre effectively suppressed the growth of all the identified bacteria while only ketoconazole at 200mg/litre inhibited the growth of all the identified fungal contaminants. Conclusion and application of results: Proteus, Erwinia, Klebsiella and Staphylococcus are the major bacterial contaminants while Aspergillus, Fusarium, Penicillium and Candida are the main fungal contaminants of banana in vitro cultures. These contaminants can effectively be eliminated by incorporation in the growth media of gentamicin, rifampicin and chloramphenicol each at 150mg/litre and ketoconazole at 200mg/litre. Further studies are required to investigate the negative side-effects of these antibiotics and antifungal agents on the growth and genetic stability of banana in vitro cultures.