Browsing by Author "Jerome Kubiriba"

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Allometric relationships and carbon content for biomass-carbon estimation of East African Highland Bananas (Musa spp. AAA-EAHB) cv. Kibuzi, Nakitembe, Enyeru and Nakinyika
(Afr. J. Agric. Res., 2017-05-03) Daphine Kamusingize; Jackson Mwanjalolo Majaliwa; Everline Komutunga; Susan Tumwebaze; Kephas Nowakunda; Priver Namanya; Jerome Kubiriba
Globally, interests to increase carbon stocks have gained momentum in both woody and non-woody ecosystems. Despite efforts made to generate appropriate methods to estimate these stocks, most equations developed do not cater for intraspecific variabilities across e.g. species, regions or growth stages; especially in the case of bananas. Therefore, there is need to develop more robust equations to improve on the precision of biomass-carbon prediction especially at local scales to facilitate estimation of specific carbon stocks often lost in global assessments. This study aimed at developing cultivar- specific biomass estimation relationships and determining carbon content of EAHB cultivars at two growth stages. Plant data were collected purposively using destructive sampling techniques on farmers’ plots for 4 cultivars (Kibuzi, Nakitembe, Enyeru and Nakinyika) in two agro-ecological zones: the L. Victoria crescent and the South-western farmlands in the districts of Lwengo and Mbarara respectively. Results show that biomass differed across cultivars (P<0.001); hence four equations (Enyeru, Nakinyika, Kibuzi_Nakitembe and Generic) were developed following an exponential function, y=Aexp(ax), using diameter at breast height (DBH) as the predictor variable with an R2 range of 82-94%. EAHB mean carbon content varied significantly with growth stage (P<0.05) (47.6% for maiden plants before flowering and 48.8% for mature plants with a developed bunch). This study concludes that it is important to develop cultivar-specific equations for biomass-carbon estimation of EAHB cultivars to help assess their contribution to the carbon cycle especially in future studies.
Analysis of Genetic Diversity of Banana Weevils (Cosmopolites sordidus) (Coleoptera: Curculionidae) UsingTranscriptome-Derived Simple Sequence Repeat Markers
(Journal of Economic Entomology, 2022-01-11) Ali Milton; Dennis Muhanguzi; Allan Male; Ali Kajubi; Stephen Buah; Jerome Kubiriba; Robooni Tumuhimbise
The banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) is an economically important insect pest of bananas. It causes up to 100% yield losses and substantial lifespan reduction in bananas. Advances in genomics, proteomics, and sequencing technologies have provided powerful pathways to genotyping disastrous pests such as C. sordidus. However, such technologies are often not available to the majority of rural subtropical African banana growers and pest control managers. This study was there- fore motivated by the need to create cheap and easily accessible C. sordidus genotyping methods that could be deployed by banana pest control managers to the bene t of C. sordidus control programs in the tropics where such advanced technologies are not readily accessible. We used an in-house C. sordidus transcriptome from the an-ongoing study from which we mined an array of simple sequence repeat (SSR) markers. Of these, six highly polymorphic transcriptome-derived SSR markers were used to successfully genotype within and among banana weevil population genetic diversity of 12 C. sordidus populations collected from four banana- growing agro-ecological zones (AEZs) in Uganda. The developed transcriptome-derived SSR markers can be used by researchers in population genetics for characterization of the C. sordidus and identification of new genes that are linked to traits of particular interest.The significant genetic diversity revealed in C. sordidus provides pertinent information for integrated pest management strategies.
Banana for food and fibre: The position of Uganda’s banana smallholder farmers
(Wageningen University & Research, 2023-03-06) Daphine Kamusingize; Esther Ronner; Godfrey Taulya; Priver Namanya; Jerome Kubiriba; Katrien Descheemaeker
• Growing global interest in utilization of agricultural residues for bio- based industries (e.g., Sarangi et al., 2023). • Uganda, with over 80% of farmers producing bananas, is scaling up its level of banana fibre production. • But, due to potential risks such as food insecurity and barriers like insufficient information, not all farmers may be positioned to benefit or actively engage in fibre production.
Changing Dynamics in the Spread and Management of Banana Xanthomonas Wilt Disease in Uganda Over Two Decades
(Phytobiomes Journal, 2023-01-17) Jerome Kubiriba; Rockefeller Erima; Arthur K. Tugume; William Tinzaara; Wilberforce K. Tushemereirwe
Banana Xanthomonas wilt (BXW) is a destructive disease caused by Xanthomonas vasicola pv. musacearum (Xvm), a bacterium that indiscriminately infects all banana varieties grown in East and Central Africa (ECA). In this region, BXW was first reported in 2001 in Uganda and was projected to eliminate >90% of Uganda’s banana crops (worth USD4 billion) if not controlled in less than 10 years. Lack of basic information led to application of control approaches that were based on similarity of BXW symptoms to those of Moko disease of banana. However, the approaches were unsuccessful and, in 7 to 9 years, BXW had covered six countries and threatened to wipe out the banana industry in ECA. However, BXW has been tamed to date, mainly due to relentless and systematic deployment of carefully crafted and packaged cultural control practices based on epidemiological information generated within target banana cropping ecosystems. In Uganda, the initial “top-down” communication approaches reached >85% of banana farming communities but did not mobilize the communities enough into action; hence, only 30% impact in controlling BXW was registered. In contrast, participatory approaches mobilized farming communities into action and effectively controlled BXW at field and community levels to near eradication. The approaches effectively controlled BXW in Uganda and, consequently, in eastern Kenya, northern Tanzania, Rwanda, Burundi, and the Democratic Republic of Congo. This article reviews step-wise processes leading to success over the 2 decades and identifies critical research gaps. Deployment of resistant genotypes is urgently needed as a significant addition to the BXW management toolbox to create BXW-free banana cropping systems in ECA.
Early Withering of Enlarged Ovules in Pollinated Fruits of Bananas (Musa spp.) Suggest Abortion after Fertilization
(Horticulturae, 2022-05-10) Allan Waniale; Settumba B. Mukasa; Arthur K. Tugume; Jerome Kubiriba; Wilberforce K. Tushemereirwe; Robooni Tumuhimbise
Sterility in edible bananas is as a result of a long history of anthropogenic-driven selection for sterile genotypes, since seed is not desirable in fruit pulp for human consumption. However, this poses a challenge to conventional genetic improvement by slowing breeding pipelines. In this study, we investigated whether pollen tubes reach all parts of the ovary, the position of fertilized ovule development in fruits, and potential seed set in selected banana genotypes. We selected four cultivars of East African Highland Cooking bananas (EAHBs), a Matooke hybrid ‘222K-1’, improved diploid ‘2905’, and wild bananas ‘Zebrina (G.F.)’ and ‘Calcutta 4’. There was evidence of pollen tubes in the distal, mid and proximal sections of the fruit, irrespective of hand position and genotype. Fertilization, as indicated by an increase in ovule size, happened along the entire length of the fruit but complete development was biased at the distal end in some genotypes. There were some differences in ovule fertilization rates between hands, with distal hands having more ovules and higher ovule fertilization rates. Ovule fertilization happens in bananas but the vast majority aborts, especially at the proximal end of the ovary. Ovule fertilization rates are generally much lower than available ovules.
Evaluation of a lateral flow device for in-field detection of Banana Xanthomonas Wilt and its application in tracking the systemicity of Xanthomonas campestris pv. musacearum
(Afr. J. Agric. Res., 2016-06-13) Georgina Karamura; Dennis Ochola; Julian Smith; Jerome Kubiriba; Eldad Karamura
Early detection of Banana Xanthomonas Wilt (BXW) in the field and immediate destruction of infected plants or plant tissue are key control methods to prevent the introduction and spread of BXW. This requires rapid, cost-effective and an on- site diagnostic tool to detect the bacterium, Xanthomonas campestris pv musacearum (Xcm). Polymerase chain reaction (PCR) detection technique for BXW is efficient but requires expensive equipment and knowledgeable expertise; this limits PCR application to the laboratory. This study therefore was carried out to evaluate the enzyme-linked immunosorbent assay (ELISA) tool configured as a lateral flow device (LFD) for detection of Xcm. Studies on the systemicity of Xcm in banana were carried out using the BXW-LFD in a field trial of 300 banana plants of Pisang Awak inoculated with the Xcm at Kiifu Forest, Mukono District, Uganda. Pseudo-stem samples from symptomatic and asymptomatic suckers were collected and tested with the LFD and the results compared with conventional PCR using the GspDm BXW primers. The LFD was able to detect Xcm 3 days post inoculation (dpi), 2 cm above and below inoculation site, 15 to 35 days in the pseudo-stem, 35 to 42 days to reach the corm and 81 days in the lateral roots. The rate of Xcm movement in banana was found to be sigmoid in nature, leveling off as the bacteria moved down the pseudo-stem towards the corm. Conventional PCR was only 24% more sensitive than the LFD. The use of the BXW LFD can therefore boost BXW control measures through improved surveillance and quarantine services to arrest the introduction and spread of the disease within and between national borders.
Inhibition Of Cell Death As An Approach For Development Of Transgenic Resistance Against Fusarium Wilt Disease
(Afr. J. Biotechnol., 2016-04-17) Betty Magambo; Khanna Harjeet; Geofrey Arinaitwe; Sali Tendo; Ivan Kabiita Arinaitwe; Jerome Kubiriba; Wilberforce Tushemereirwe; James Dale
Fusarium oxysporum f. sp. cubense (Foc) is one of the major threats to dessert banana (Musa spp.) production. In Uganda, ‘Sukali Ndiizi’ is one of the most popular dessert banana cultivars and it is highly susceptible to Fusarium wilt. Development of resistant cultivars through transgenic approaches has shown to offer one of the most effective control options for most diseases. The transgenic approaches for providing plant disease resistance have mainly been through either enzymatic destruction of pathogen structures, neutralization of pathogen and its products or production of metabolites that eventually kill the pathogen. However in recent years, methods that prevent cell death of host plant after infection especially for necrotrophic pathogens like F. oxysporum have registered success in providing resistance in several crops. We investigated whether the transgenic expression of a programmed cell death inhibition gene in Sukali Ndiizi could be used to confer Fusarium resistance to Foc race 1. Embryogenic cell suspensions of cv. ‘Sukali Ndiizi, were stably transformed with a synthetic, plant-codon optimise mCed-9 gene. Twenty-eight independently transformed plant lines were regenerated. The lines were inoculated with Foc race 1 and observed for 13 weeks in small-plant glasshouse. Three transgenic lines showed significantly lower internal and external disease symptoms than the wild-type susceptible ‘Sukali Ndiizi’ banana plants used as controls. This is the first report from Africa on the generation of Fusarium wilt tolerant transgenic ‘Sukali Ndiizi’, a very popular but rapidly diminishing African dessert banana.
Mapping spatial distribution and geographic shifts of East African highland banana (Musa spp.) in Uganda
(PLOS One, 2022-02-17) Dennis Ochola; Bastiaen Boekelo; Gerrie W. J. van de Ven; Godfrey Taulya; Jerome Kubiriba; Piet J. A. van Asten; Ken E. Giller
East African highland banana (Musa acuminata genome group AAA-EA; hereafter referred to as banana) is critical for Uganda’s food supply, hence our aim to map current distribution and to understand changes in banana production areas over the past five decades. We collected banana presence/absence data through an online survey based on high-resolution satellite images and coupled this data with independent covariates as inputs for ensemble machine learning prediction of current banana distribution. We assessed geographic shifts of production areas using spatially explicit differences between the 1958 and 2016 banana distribution maps. The biophysical factors associated with banana spatial distribution and geographic shift were determined using a logistic regression model and classification and regression tree, respectively. Ensemble models were superior (AUC = 0.895; 0.907) com- pared to their constituent algorithms trained with 12 and 17 covariates, respectively: random forests (AUC = 0.883; 0.901), gradient boosting machines (AUC = 0.878; 0.903), and neural networks (AUC = 0.870; 0.890). The logistic regression model (AUC = 0.879) performance was similar to that for the ensemble model and its constituent algorithms. In 2016, banana cultivation was concentrated in the western (44%) and central (36%) regions, while only a small proportion was in the eastern (18%) and northern (2%) regions. About 60% of increased cultivation since 1958 was in the western region; 50% of decreased cultivation in the eastern region; and 44% of continued cultivation in the central region. Soil organic carbon, soil pH, annual precipitation, slope gradient, bulk density and blue reflectance were associated with increased banana cultivation while precipitation seasonality and mean annual temperature were associated with decreased banana cultivation over the past 50 years. The maps of spatial distribution and geographic shift of banana can support targeting of context-specific intensification options and policy advocacy to avert agriculture driven environmental degradation.
Ploidy level of the banana (Musa spp.) accessions at the germplasm collection centre for the East and Central Africa
(Afr. J. Biotechnol., 2016-08-21) Deborah Karamura; Robooni Tumuhimbise; Sedrach Muhangi; Moses Nyine; Micheal Pillay; Reuben Ssali Tendo; David Talengera; Priver Namanya; Jerome Kubiriba; Eldad Karamura
Banana Germplasm Collection serves as a source of useful genes for banana breeding. However, insufficient and/or inaccurate information on the ploidy level of the germplasm renders its utilization in breeding difficult. The objective of this study was to determine and validate the ploidy level of 120 banana accessions in the ex situ germplasm collection centre for the East and Central Africa, located in Mbarara, Uganda. Flow cytometric analysis of the nuclear DNA content was used to determine the ploidy level of the accessions. Results indicate that accessions: Bura, Diana, Kambani-Rungwe, Paji and Pagatau, and Rungwe that were previously classified as diploids are actually triploids, whereas Selangor previously known to be a diploid is a tetraploid. Accessions such as Galeo, Mwitupemba and Ntindi 1 that were previously classified as triploids were found diploids. GT, FHIA 25 and Muzungu Mwekundu that were considered as tetraploids, were found triploids. The information generated will guide correct placement of these accessions in the regional germplasm collection centre for the East and Central Africa and their utilization in banana breeding.
TARIBAN1, TARIBAN2, TARIBAN3, and TARIBAN4 ‘Matooke’ Cooking Banana Cultivars for the Great Lakes Region of Africa
(HortScience, 2022-11-23) Noel A. Madalla; Cornel Massawe; Mpoki Shimwela; Daud Mbongo; Grace Kindimba; Jerome Kubiriba; Ivan Arinaitwe; Kephas Nowakunda; Priver Namanya; Robooni Tumuhimbise; Asher W. Okurut; Adolf Saria; Munguatosha Ngomuo; Rony Swennen; Allan F. Brown; Michael Batte; Sebastien Carpentier; Inge Van den Bergh; Rhiannon Crichton; Pricilla Marimo; Eva Weltzien; Rodomiro Ortiz
Bananas and plantains (Musa sp.) are important staple and income-generating fruit crops for millions of people worldwide (Robinson and Sauco 2010; Ssebuliba et al. 2005). They are edible and vegetatively propagated parthenocarpic species (Ortiz 1997; Simmonds 1962). East African highland bananas (EAHBs) are a dis- tinct group of cultivars found only in the highland of African Great Lakes region, where the “greatest mass of bananas in the world” are found (Simmonds 1966). Bananas are important in the food economy of millions of people in this region, with annual per capita consumption estimated to be between 250 and 600 kg (Karamura et al. 2012). These triploid (2n 5 3x 5 33 chromosomes) cultivars are known locally as Matooke. When fully ripe, they can be eaten raw like dessert bananas; however, be- cause their pulp is insipid, they are mostly eaten after cooking. Shepherd (1957) referred to them as the ‘Lujugira-Mutika’ subgroup of the AAA genome group. They are also known by its acronym (EAHBs) because they thrive on the East African plateau at altitudes ranging from 900 to 1800 m above sea level (Davies 1995). A small group of these EAHBs are processed into a beverage, and called beer or ‘Mbidde’ bananas.
The Status of Research for the Management of the Banana Weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) in Sub-Saharan Africa
(European Journal of Agriculture and Food Sciences, 2022-03-25) Elyeza Bakaze; William Tinzaara; Cliff Gold; Jerome Kubiriba
The banana weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae] is a major pest of East African highland bananas and plantains. Its larvae bore in corm tissue damaging the root system, disrupting nutrient and water uptake, compromising plant anchorage, reducing yield, and shortening plantation life. Yield losses in bananas and plantains may exceed 50%. Available technologies for the management of the pest include cultural control, biological control, and chemical control. These methods may be costly, labor intensive, or ecologically unsustainable. Such effects, together with developed pesticide resistance, have led to various efforts searching for sustainable alternatives. To achieve this, there is a need to understand the biology of the pest and the currently available management options which includes use of cultural practices, resistant banana varieties, biological and microbial control, pheromone trapping and chemical and botanical insecticides. This article reviews the research status concerning C. sordidus biology, distribution, management options, including current innovations such as genome editing, and suggests future research directions for the management of the pest. Research findings suggest that no single control strategy will provide complete control. The integration of appropriate conventional C. sordidus management options with genetic engineering and other ecologically friendly methods such as use of botanicals and infochemicals will manage the pest and sustainably increase banana production.
Transgenic East African Highland Banana Plants Are Protected against Radopholus similis through Host-Delivered RNAi
(International Journal of Molecular Sciences, 2023-07-28) Henry Shaykins Mwaka; Lander Bauters; Josephine Namaganda; Shirley Marcou; Priver Namanya Bwesigye; Jerome Kubiriba; Guy Smagghe; Wilberforce Kateera Tushemereirwe; Godelieve Gheysen
The burrowing nematode Radopholus similis is considered a major problem of intensive banana cultivation. It can cause extensive root damage resulting in the toppling disease of banana, which means that plants fall to the ground. Soaking R. similis in double-stranded (ds) RNA of the nematode genes Rps13, chitin synthase (Chs-2), Unc-87, Pat-10 or beta-1,4-endoglucanase (Eng1a) suppressed reproduction on carrot discs, from 2.8-fold (Chs-2) to 7-fold (Rps13). The East African Highland Banana cultivar Nakitembe was then transformed with constructs for expression of dsRNA against the same genes, and for each construct, 30 independent transformants were tested with nematode infection. Four months after transfer from in vitro culture to the greenhouse, the banana plants were transferred to a screenhouse and inoculated with 2000 nematodes per plant, and thirteen weeks later, they were analyzed for several parameters including plant growth, root necrosis and final nematode population. Plants with dsRNA constructs against the nematode genes were on average showing lower nematode multiplication and root damage than the nontransformed controls or the banana plants expressing dsRNA against the nonendogenous gene. In conclusion, RNAi seems to efficiently protect banana against damage caused by R. similis, opening perspectives to control this pest.
Xanthomonas campestris pv. musacearum Bacterial Infection Induces Organ-Specific Callose and Hydrogen Peroxide Production in Banana
(Phyto Frontiers, 2022-01-03) Abubakar Sadik Mustafa; Benison Tugume; Jamilu E. Ssenku; Paul Ssemanda; Shahasi Y. Athman; Hannington Oryem-Origa; Jerome Kubiriba; Savithramma P. Dinesh-Kumar; Arthur K. Tugume
Xanthomonas campestris pv. musacearum (Xcm) bacteria cause banana Xanthomonas wilt (BXW), the most destructive disease of bananas in East and Central Africa. During early stages of infection in susceptible banana cultivars, incomplete systemic movement of Xcm limits bacterial colonization in the up- per organs. The mechanistic basis of this delayed movement is unknown. We hypothesized that Xcm infection triggers basal pattern-triggered immune (PTI) responses whose spatial and temporal variability along the banana’s anatomical structure accounts for initially limiting Xcm in upper organs. Hence, we examined PTI responses such as callose deposition and hydrogen peroxide (H2O2) production in different organs in response to Xcm infection in BXW-susceptible Kayinja and Mbwazirume banana cultivars and wild resistant progenitor Musa balbisiana. Xcm-induced callose increased and peaked at 14 days postinoculation (dpi) and 28 dpi as assessed by fluorescence microscopy and enzyme-linked immunosorbent assays, respectively. The levels of Xcm-induced H2 O2 and callose were highest in the pseudostems and corms, respectively, and were independent of host susceptibility or resistance to BXW. H2O2 production showed a biphasic transient pattern with an initial increase at 1-hour post Xcm inoculation (hpi), followed by a decline 3 to 6 hpi and then a second increase by 12 hpi. Our findings point to organ-specific responses to Xcm infection in bananas. The corm, which doubles as a subterranean perennating organ and interface between mother plants and lateral shoots, was the most responsive organ in callose production, whereas the pseudostem was the most responsive organ in H2O2 production, suggesting the significance of these organs in banana response to BXW.