NRU :: Browsing by Author "Karamura, Eldad"

Browsing by Author "Karamura, Eldad"

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Assessing New Banana Genotypes for Relevant Traits: Implication for Variety Selection
(Agricultural Sciences, 2020) Tumuhimbise, Robooni; Barekye, Alex; Talengera, David; Akankwasa, Kenneth; Nowakunda, Kephas; Asasira, Moreen; Karamura, Deborah; Karamura, Eldad
Understanding the performance of new crop genotypes for traits of relevance is important in selecting potential cultivars to satisfy end-users. The objective of this study was to determine the performance of new banana genotypes for bunch mass (BMS) and BMS-related traits, resistance to black Sigatoka and sensory attributes. Eight cooking banana genotypes consisting of six new hybrid genotypes selected from advanced breeding trials and two control cultivars were evaluated in a randomized complete block design for three crop cycles at three locations in Uganda. Genotype, location, crop cycle and their interaction effects were significantly different for most traits assessed. The overall top two genotypes (“9058K-2” and “8099K-16”) combining high BMS, resistance to black Sigatoka and acceptable sensory attributes were identified. These genotypes are suggested as potential commercial cultivars for release to farmers in Uganda and/or other East African countries with similar environmental conditions to those where the genotypes were tested. It should be noted that high BMS/yield and resistance to diseases are not the only factors to consider when selecting banana genotypes that meet end-user needs. A combination of high BMS/yield, acceptable sensory attributes and resistance to diseases essentially influence the selection process of banana cultivars.
Breeding banana (Musa spp.) for drought tolerance: A review
(Plant Breeding, 2020) Nansamba, Moureen; Sibiya, Julia; Tumuhimbise, Robooni; Karamura, Deborah; Kubiriba, Jerome; Karamura, Eldad
Drought is a major abiotic stress affecting banana production worldwide, leading to yield losses of up to 65%. Consequently, numerous efforts to understand and mitigate drought effects that include developing tolerant crop varieties are ongoing in several banana breeding programmes. The breeding efforts, however, have been greatly slowed down by inherent banana problems (polyploidy and male or female sterility) and complexity of drought tolerance (reportedly controlled by several genes). This review summarizes the pertinent research findings on water requirements of banana for its proper growth and productivity, symptoms of drought-sensitive varieties and field management strategies to cope with drought stress. The coping strategies deployed by resistant cultivars include high assimilation rates and water retention capacity as well as minor losses in leaf area and gaseous exchange. Reduced bunch weight, leaf chlorosis, wilting and strangled birth are underlined to be directly associated with drought susceptibility. Integration of conventional, molecular breeding and biotechnological tools as well as exploitation of the existing banana genetic diversity presents a huge opportunity for successful banana improvement.
Corm damage caused by banana weevils Cosmopolites sordidus (Germar) collected from different banana growing regions in Uganda
(Agriculture & Food Security, 2018) Twesigye, Charles K.; Ssekatawa, Kenneth; Kiggundu, Andrew; Tushemereirwe, Wilberforce; Matovu, Enock; Karamura, Eldad
In this study, both healthy tissue culture plantlets and maiden suckers of the Nakitembe cultivar were used to assess the damage level variation caused by banana weevils collected from different banana growing regions. Seventy-nine (79) tissue culture plantlets and fifty (50) suckers were established in buckets in a randomized complete block design for 5 months. Ten adult weevils (5 females and 5 males) were introduced at the base of each plant, and the buckets were covered with a weevil proof mesh. Weevil damage was estimated as a percentage at 60 days after the weevil introduction by estimating the peripheral damage (PD), total cross section corm damage (XT) and above the collar damage (ACD). Results: The results showed high differences in the PD, XI, XO and XT caused by weevils from the different zones. PD and XT ranged from 4.8–50.4 to 4.2–43.8%, respectively, caused by weevils collected from Kabale and Rakai, Kabale and Wakiso, respectively, while XI and XO varied from 0.0–42.9 to 8.3–40.4%, respectively, caused by banana weevils collected from Kabale and Rakai, Kabale and Rakai, respectively. Banana weevils from Rakai caused the highest ACD of 40.4% and no such damage was caused by banana weevils collected from western Uganda. Average ACD in suckers was 19.6% and significantly higher than that in tissue culture plants (8.5%). Conclusions and recommendations: Corm damage assessment suggests the existence of banana weevil biotypes but it is recommended that follow-up studies be carried out to confirm this phenomenon.
Determinants of Farm-Level Adoption of Cultural Practices for Banana Xanthomonas Wilt Control in Uganda
(Journal of Agricultural Science, 2013) Jogo, Wellington; Karamura, Eldad; Tinzaara, William; Kubiriba, Jerome; Rietveld, Anne
Understanding the factors influencing farmers’ adoption decisions of the disseminated Banana Xanthomonas wilt (BXW) control package is critical for successful management of the disease. This paper analysed the determinants of farmers’ decisions to adopt the control package by smallholder banana farmers in Uganda. A binomial Logit model is applied to household survey data collected from 350 households. Results from the study show that household labour availability, technology package attributes such as labour demand and perceived effectiveness of the practices in managing the disease; and agro-ecological location and banana production system significantly influence adoption decisions. These results suggest the need for adaptation of the technology package to better suit the needs and socio-economic conditions of smallholder farmers through a farmer participatory technology development approach that takes into account research findings, farmers’ indigenous knowledge and resource constraints to enhance adoption.
Development of two high-yielding, consumeracceptable apple banana hybrids (Musa species, AAB genome group) with resistance to Fusarium oxysporum f. sp. cubense race 1
(Journal of Plant Breeding and Crop Science, 2018) Buregyeya, Henry; Tumuhimbise, Robooni; Kubiriba, Jerome; Talengera, David; Nowankunda, Kephas; Arinaitwe, Geofrey; Tushemereirwe, Wilberforce K.; Karamura, Deborah; Karamura, Eldad; Rubaihayo, Patrick
Fusarium wilt of bananas (Musa species) is caused by Fusarium oxysporum f. sp. cubense (Foc). Foc race 1 in particular affects dessert bananas in Uganda, causing >60% yield loss. This study was conducted to assess the performance of two new apple banana genotypes for bunch yield, resistance to Foc race 1 and consumer acceptability. The new apple banana genotypes (NAMU1 and NAMU2), along with two check cultivars, one susceptible but preferred by consumers (Sukali ndiizi) and the other resistant (Yangambi-KM5), were evaluated at the National Agricultural Research Laboratories in Uganda. Bunch yields of the two new apple bananas were higher than those of check cultivars by >50%. NAMU1 and Yangambi-KM5 showed no symptoms of Foc race 1, whereas NAMU2 showed mild symptoms on its corms. Sukali ndiizi showed severe pseudostem splitting and corm discoloration as the key symptoms of Foc race 1. The consumer acceptability of NAMU1 and NAMU2 was as high as that of Sukali ndiizi, implying that they can be perfect substitutes for the Foc race 1 susceptible Sukali ndiizi.
Does gender matter in effective management of plant disease epidemics? Insights from a survey among rural banana farming households in Uganda
(Journal of Development and Agricultural Economics, 2018) Mutebi Kikulwe, Enoch; Okurut, Stanslus; Ajambo, Susan; Gotor, Eisabetta; Tendo Ssali, Reuben; Kubiriba, Jerome; Karamura, Eldad
Crop diseases significantly suppress plant yields and in extreme cases wipe out entire crop species threatening food security and eroding rural livelihoods. It is therefore critical to estimate the extent to which shocks like disease epidemics can affect food availability and the capacity of smallholder farmers to mitigate and reverse the effects of such shocks. This study utilizes sex-disaggregated data from 341 households in Uganda to analyze: first, gender and access to agricultural resources and their control; second, whether men and women in the targeted banana-farming communities share similar perceptions toward the effectiveness of the banana Xanthomonas wilt (BXW) control technologies and their respective information dissemination pathways; third, whether gender and farmer perceptions influence on farm adoption of BXW management practices. Lastly, it determines the impact of adoption of BXW control practices on food security. Results show that whereas most household assets are jointly owned, men have more individual ownership, control, and decision-making on income from household assets than women. Perceptions on effectiveness of BXW control practices and communication channels also differed between men and women. Men rated cutting down of infected plants to be more effective than women, but tissue culture, removal of male buds and disinfecting of farm tools were perceived to be equally effective by both men and women. In addition, apart from newspapers which were more effective in delivering BXW information to men, we found no differences in the effectiveness of other BXW information sources. More importantly, the study finds both gender and farmer perceptions on BXW control to significantly affect adoption of BXW control practices and household food security. For better and sustainable management of plant epidemics in Uganda, it is therefore critical that existing gender-based and underlying perception constraints are addressed.
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
(African Journal of Agricultural Research, 2016) Karamura, Georgina; Ochola, Dennis; Smith, Julian; Kubiriba, Jerome; Karamura, Eldad
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.
Farmers’ awareness and application of banana Xanthomonas wilt control options: The case of Uganda and Kenya
(Journal of Development and Agricultural Economics, 2011) Jogo, Wellington; Karamura, Eldad; Kubiriba, Jerome; Tinzaara, William; Rietveld, Anne; Onyango, Margaret; Odongo, Michael
Banana is a key staple and cash crop in east and central Africa. However, the recent outbreak of Banana Xanthomonas wilt (BXW) has threatened farmers whose livelihoods depend on the crop. Since 2002, stakeholders embarked on campaigns to sensitize farmers on the disease and its management. This study evaluated the effectiveness of these efforts by examining farmers’ awareness of the disease, control options and their application in Uganda and Kenya. Data on BXW distribution and incidence, farmers’ awareness of symptoms, mechanisms of spread and control options of the disease and banana production were collected through household surveys conducted in 2010. The results indicated that most farmers (> 90%) were aware of the disease and its symptoms and more than 50% were aware of the recommended control measures. Farmers obtained information on the disease from multiple sources but farmer-to-farmer interaction was the main source suggesting the key role rural social networks play in managing the disease. Not all affected farmers were able to apply control measures due to cost of intervention, lack of labour and inputs. The study recommends strengthening of linkages among stakeholders for better coordination of efforts and participatory development and promotion of farmer-oriented interventions that address farmer constraints.
Fine-tuning banana Xanthomonas wilt control options over the past decade in East and Central Africa
(European journal of plant pathology, 2014) Blomme, Guy; Jacobsen, Kim; Ocimati, Walter; Beed, Fen; Ntamwira, Jules; Sivirihauma, Charles; Ssekiwoko, Fred; Nakato, Valentine; Kubiriba, Jerome; Tripathi, Leena; Tinzaara, William; Mbolela, Flory; Lutete, Lambert; Karamura, Eldad
Xanthomonas wilt, caused by Xanthomonas campestris pv. musacearum has, since 2001, become the most important and widespread disease of Musa in East and Central Africa. Over the past decade, new research findings and especially feedback from smallscale farmers have helped in fine-tuning Xanthomonas wilt control options. During the initial years of the Xanthomonas wilt epidemic in East Africa, the complete uprooting of diseased mats and the burning or burying of plant debris was advocated as part of a control package which included the use of clean garden tools and early removal of male buds to prevent insect vector transmission. Uprooting a complete mat (i.e. the mother plant and a varying number of lateral shoots) is understandably time-consuming and labour intensive and becomes very cumbersome when a large number of diseased mats have to be removed. Recent research findings suggest that Xcm bacteria do not colonize all lateral shoots (i.e. incomplete systemicity occurs) and even when present that this does not necessarily lead to symptom expression and disease.
Fusarium oxysporum Race 1 resistance and quality traits variations in apple banana germplasm
(Journal of Plant Breeding and Crop Science, 2020) Buregyeya, Henry; Tumuhimbise, Robooni; Matovu, Moses; Tumwesigye, Kashub S.; Kubiriba, Jerome; Nowankunda, Kephas; Tushemereirwe, Wilberforce K.; Karamura, Deborah; Karamura, Eldad; Kityo, Robert M.; Rubaihayo, Patrick
Musa species, AAB genome group, commonly known as Sukali Ndizi (SND) in Uganda, has attained a substantial commercial value in the recent past owing to its superior fruit quality attributes and better prices. However, its sustainable production and productivity are highly threatened by Fusarium wilt. To facilitate large scale area expansion of this important dessert banana, the present study was carried out to identify the near-ideotypic lines of best quality fruit traits that are also resistant to Fusarium wilt. Nineteen SND ecotypes were subsequently collected from nine key SND growing districts of Uganda and evaluated in the field and laboratory for different fruit quality attributes and response to Fusarium wilt. Results showed a wide diversity among SND ecotypes for fruit-quality traits (fruit pulp texture, flavor and taste). The ecotypes were, however, not significantly different (p > 0.05) for susceptibility to FOC race 1. Cluster analysis based on organoleptic and physio-chemical properties grouped the 19 ecotypes into two major-clusters, each of which was also split into two sub-clusters. Individual subclusters summarize levels of similarity amongst the different ecotypes. The study confirmed the presence of diversity in SND germplasm that could be exploited for SND genetic improvement of the crop through hybridization and selection.
Genetic Analysis of Weevil (Cosmopolites Sordidus) Resistance in an F2 Diploid Banana Population
(Journal of Plant Breeding and Genetics, 2015) Arinaitwe, Ivan K.; Barekye, Alex; Kubiriba, Jerome; Sadik, Kassim; Karamura, Eldad; Edema, Richard
The East African highland bananas (Musa spp. AAA), an important staple food in Uganda, are highly susceptible to the banana weevil (Cosmopolites sordidus Germar). Sources of host plant resistance to the banana weevil exist in wild diploid bananas. The use of wild diploid bananas to improve East African highland bananas can be facilitated by studying genetics of host plant resistance of inter-diploid crosses. The objectives of this study were a) to identify segregating weevil resistance and agronomic traits in an F2 diploid population, and, b) to determine the inheritance of banana weevil resistance and agronomic traits based on an F2 banana diploid population. An F1 population developed from Musa acuminata subsp. banksii acc. Kasaska (ITC0591) and M. acuminata subsp. microcarpa acc. Borneo (ITC0253) was selfed to generate an F2 diploid population. The F2 population was screened against weevil resistance and agronomic traits in the laboratory, pot and field experiments. There were significant differences (P < 0.05) among the different genotypes for banana weevil resistance traits such as head capsule width, body length, body weight, larval mortality, total damage, peripheral damage, dead weevils and larvae retrieved. There were also significant differences (P < 0.05) for agronomic traits such as inner corm hardness and total corm hardness. The histograms for the banana weevil resistance traits such as head capsule width, body length, body weight and larval mortality, total damage, peripheral damage, cross sectional inner and outer damage, larvae retrieved and dead weevils showed continuous distribution. Similarly, histograms for agronomic parameters such as height of plant at flowering and girth at 1 meter at flowering showed continuous distribution. The Chi-square test of goodness of fit indicated that weevil growth and damage parameters had significant modifications of the expected 9:3:3:1 ratio for two independent loci, thus suggesting epistasis affects their inheritance.
Management of Banana Xanthomonas Wilt: Evidence from Impact of Adoption of Cultural Control Practices in Uganda
(Sustainability, 2019) Kikulwe, Enoch M.; Lule Kyanjo, Joseph; Kato, Edward; Ssali, Reuben T.; Erima, Rockefeller; Mpiira, Samuel; Ocimati, Walter; Tinzaara, William; Kubiriba, Jerome; Gotor, Elisabetta; Stoian, Dietmar; Karamura, Eldad
Banana XanthomonasWilt (BXW) is an important emerging and non-curable infectious plant pathogen in sub-Saharan Africa that can cause up to 100% yield loss, negatively impacting sustainable access to food and income to more than 100 million banana farmers. This study disentangles adopters into partial and full adopters to investigate the factors that are relevant to sustain the adoption process of BXW control practices and quantifies the impact of adopting the practices. Data from a randomly selected sample of 1200 banana farmers in Uganda where the disease is endemic was used. A multinomial logit model was used to determine the factors a ecting adoption of control practices and augmented inverse probability weighting was employed to estimate the impacts of adoption on banana productivity and sales. Results show that training a woman farmer and having diverse sources of information about BXW control practices increased adoption of the control practices and reduced the disease incidences. Farmers who adopted all the recommended control practices achieved significantly the highest values of banana production and sales. We conclude that improving information access through farmers’ preferred communication channels, having women-inclusive trainings, and a combination of cultural practices are e ective ways for sustaining adoption of the control practices.
Mode of inheritance for resistance to FOC Race 1 and fruit quality traits in Sukali Ndizi cultivar of Banana
(Journal of Plant Breeding and Crop Science, 2021) Buregyeya, Henry; Tumwesigye, Kashub S.; Matovu, Moses; Nowakunda, Kephas; Namanya, Priver; Tushemereirwe, Wilberforce K.; Karamura, Eldad; Rubaihayo, Patrick
Information on the genetic control of resistance to Fusarium oxysporum f.sp.cubense (FOC) race (1) and fruit quality traits in Sukali Ndizi cultivar of banana is key to its genetic improvement. The mode of resistance to Fusarium wilt in Sukali Ndizi was analyzed in 536 hybrids and 5 parental lines and quality attributes in 137 hybrids and two parental lines, grown in same environment. Fruit quality was assessed by physical measurements and fruit composition whereas resistance to Fusarium wilt was assessed by corm discoloration symptoms. All the assessed traits were quantitatively inherited. Flavor attributes, and pulp texture showed a predominance of additive inheritance with complementary gene action whereas total soluble solutes showed non-additive gene with dominant gene action. Fruit acidity had incomplete dominancy with the genetic model explained by both single gene and certain multiple genes. Resistance to Fusarium wilt showed dominant gene action and polygenic effects. Involvement of a few genes governing wilt resistance suggested the ease of breeding for this trait. Pedigree breeding method could be recommended for incorporating various traits in (cv. Sukali Ndizi) of banana.
‘NABIO808’ (Syn. ‘NAROBAN5’): A tasty cooking banana cultivar with resistance to pests and diseases
(Crop Breeding and Applied Biotechnology, 2019) Tumuhimbise, Robooni; Buregyeya, Henry; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Barekye, Alex; Tendo, Reuben S.; Namagembe, Betty; Muhangi, Sedrach; Kazigye, Francis; Talengera, David; Tindamanyire, Jimmy; Akankwasa, Kenneth; Nabulya, Gertrude; Namaganda, Josephine; Waswa, William; Kushaba, Abias; Namuddu, Mary; Oyesigye, Naboth; Namanya, Priver; Arinaitwe, Ivan K.; Waniale, Allan; Karamura, Deborah; Karamura, Eldad
‘NABIO808’ is a newly released, conventionally-bred triploid cooking banana cultivar in Uganda. It produces an average bunch yield of 54.5 t ha-1 yr-1 and is resistant to weevils, nematodes, and black Sigatoka. Additionally, its food is yellow, soft, and tasty, like that of most preferred landrace cultivars, making it more acceptable to end-users.
Ploidy level of the banana (Musa spp.) accessions at the germplasm collection centre for the East and Central Africa
(African Journal of Biotechnology, 2016) Karamura, Deborah; Tumuhimbise, Robooni; Muhangi, Sedrach; Nyine, Moses; Pillay, Micheal; Ssali Tendo, Reuben; Talengera, David; Namanya, Priver; Kubiriba, Jerome; Karamura, Eldad
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.
Selection of cooking banana genotypes for yield and black Sigatoka resistance in different locations in Uganda
(Journal of Plant Breeding and Crop Science, 2016) Tumuhimbise, Robooni; Buregyeya, Henry; Barekye, Alex; Ssali, Reuben T.; Talengera, David; Kubiriba, Jerome; Muhangi, Sedrach; Namagembe, Betty; Namanya, Priver; Arinaitwe, Geofrey; Tushemereirwe, Wilberforce K.; Karamura, Deborah; Karamura, Eldad
It is imperative to systematically evaluate new banana genotypes in different locations before national release. This enables selection and recommendation of superior genotypes as new varieties for a wider range of environments. The objective of the present study was to select banana genotypes with stable and high performance for bunch yield and leaf black Sigatoka resistance. Eleven cooking banana genotypes developed by the Uganda National Agricultural Research Organization in collaboration with Bioversity International, and two check varieties were evaluated in multi-location preliminary yield trials in Uganda. Data collected were analyzed using Additive Main Effects and Multiplicative Interaction (AMMI) model, AMMI Stability Value, and Genotype Selection Index (GSI). Genotype × location interaction was significant for all the traits assessed. Most of the new genotypes had low interaction effects with locations for bunch yield (69.2%) and black Sigatoka (92.3%). The most stable genotypes for bunch yield were NABIO815, NABIO1117, NABIO216 and NABIO306 whereas for black Sigatoka resistance, were NABIO1011, NABIO815, NABIO1009 and NABIO216. Using the GSI that defines the most desirable genotypes as those that combine high agronomic performance and stability across environments, four genotypes (NABIO306, NABIO1011, NABIO808 and NABIO1009) were selected. These genotypes, in addition to their high performance for agronomic traits and stability, had soft and yellow fruit pulp on cooking, and will be advanced on farm for further evaluation.

Browsing by Author "Karamura, Eldad"

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