NRU :: Browsing by Author "Tumuhimbise, Robooni"

Browsing by Author "Tumuhimbise, Robooni"

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Analysis of Genetic Diversity of Banana Weevils (Cosmopolites sordidus) (Coleoptera: Curculionidae) Using Transcriptome-Derived Simple Sequence Repeat Markers
(Journal of Economic Entomology, 2022) Milton, Ali; Muhanguzi, Dennis; Male, Allan; Kajubi, Ali; Buah, Stephen; Kubiriba, Jerome; Tumuhimbise, Robooni
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 therefore 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 benefit 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 bananagrowing 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.
Application of Pollen Germination Media on Stigmas during Pollination Increases Seed Set in East African Highland Cooking Bananas (Musa spp.)
(Agronomy, 2021) Waniale, Allan; Swennen, Rony; Settumba, B. Mukasa; Tugume, Arthur K.; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Amah, Delphine; Tumuhimbise, Robooni
Seed set in East African Highland Cooking bananas (EAHBs) is extremely low and therefore hampers breeding. Pollen–pistil interaction is a key contributing factor. We assessed the effect of pollen germination media (PGM) on seed set in EAHBs. Five EAHB cultivars were pollinated with pollen from the wild banana ‘Calcutta 4’. Glucose-based PGM sprayed on freshly emerged stigmas significantly increased seed set per 100 fruits per bunch. Increases were 73.5% in ‘Enzirabahima’, 39.9% in ‘Mshale’, and 302.4% in ‘Nshonowa’. However, PGM did not increase seed set in the female sterile ‘Mlelembo’ and ‘Nakitembe’. As larger bunches were more fertile, good field management practices are also recommended to get more seed to improve breeding efficiency.
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.
Bananas and Plantains (Musa spp.)
(Springer, Cham, 2017) Brown, Allan; Tumuhimbise, Robooni; Amah, Delphine; Uwimana, Brigitte; Nyine, Moses; Mduma, Hassan; Talengera, David; Karamura, Deborah; Kuriba, Jerome; Swennen, Rony
With a production of 145 million metric tons worldwide (worth 26.5 billion Euro), banana (Musa spp.) is one of the world’s most important staple food crops and arguably the world’s most popular fruit in terms of international trade (FAO 2014). Banana and plantains (Musa spp.), collectively referred to here as bananas, are grown in more than 135 countries and found in most tropical and subtropical regions around the world. While industrialized nations view banana primarily as a dessert item, many regions of the developing world consider cooking bananas and plantains as essential staples that contribute significantly to the caloric intake of low-income subsistence farmers. Although sensitivity to photoperiod has been noted in certain cultivars (Fortescue et al. 2011), banana is an almost nonseasonal crop that reliably provides a carbohydrate source year-round which makes it vitally important to both nutrition and food security.
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.
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.
Early Withering of Enlarged Ovules in Pollinated Fruits of Bananas (Musa spp.) Suggest Abortion after Fertilization
(Horticulturae, 2022) Waniale, Allan; Mukasa, Settumba B.; Tugume, Arthur K.; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Tumuhimbise, Robooni
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.
The East African Highland Cooking Bananas ‘Matooke’ preferences of Farmers and Traders: Implications for Variety Development
(International Journal of Food Science & Technology, 2021) Akankwasa, Kenneth; Marimo, Pricilla; Tumuhimbise, Robooni; Asasira, Moreen; Khakasa, Elizabeth; Mpirirwe, Innocent; Forsythe, Lora; Nowakunda, Kephas
‘Matooke’ is a staple food made from Highland cooking bananas in the Great Lakes region of East Africa. Genetic improvement of these bananas for resistance to pests and diseases has been a priority breeding objective. However, there is insufficient information on fruit quality characteristics that different users prefer, resulting in sub-optimal adoption of new varieties. This study identified matooke characteristics preferred by farmers and traders, using survey data from 123 farmers, 14 focus group discussions and 40 traders. Gender differences were considered. The main characteristics that were found to drive variety preferences were agronomic (big bunch, big fruits) and quality (soft texture, good taste, good aroma, yellow food). There were minimal geographical and gender differences for trait preferences. Quality characteristics need to be defined in terms of physical–chemical underpinnings so that breeding programmes can apply accurate high-throughput systems, thereby improving adoption and impact of new banana varieties.
Eleven years of breeding efforts to combat cassava brown streak disease
(Breeding Science, 2016) Sezi Kawuki, Robert; Kaweesi, Tadeo; Esuma, Williams; Pariyo, Anthony; Kayondo, Ismail Siraj; Ozimati, Alfred; Kyaligonza, Vincent; Abaca, Alex; Orone, Joseph; Tumuhimbise, Robooni; Nuwamanya, Ephraim; Abidrabo, Philip; Amuge, Teddy; Ogwok, Emmanuel; Okao, Geoffrey; Wagaba, Henry; Adiga, Gerald; Alicai, Titus; Omongo, Christopher; Bua, Anton; Ferguson, Morag; Kanju, Edward; Baguma, Yona
Cassava (Manihot esculenta Crantz) production is currently under threat from cassava brown streak disease (CBSD), a disease that is among the seven most serious obstacles to world’s food security. Three issues are of significance for CBSD. Firstly, the virus associated with CBSD, has co-evolved with cassava outside its center of origin for at least 90 years. Secondly, that for the last 74 years, CBSD was only limited to the low lands. Thirdly, that most research has largely focused on CBSD epidemiology and virus diversity. Accordingly, this paper focuses on CBSD genetics and/or breeding and hence, presents empirical data generated in the past 11 years of cassava breeding in Uganda. Specifically, this paper provides: 1) empirical data on CBSD resistance screening efforts to identify sources of resistance and/or tolerance; 2) an update on CBSD resistance population development comprising of full-sibs, half-sibs and S1 families and their respective field performances; and 3) insights into chromosomal regions and genes involved in CBSD resistance based on genome wide association analysis. It is expected that this information will provide a foundation for harmonizing on-going CBSD breeding efforts and consequently, inform the future breeding interventions aimed at combating CBSD.
Evaluation of banana germplasm and genetic analysis of an F1 population for resistance to Fusarium oxysporum f. sp. cubense race 1
(Euphytica, 2019) Kabiita Arinaitwe, Ivan; Teo, Chee How; Kayat, Fatimah; Tumuhimbise, Robooni; Uwimana, Brigitte; Kubiriba, Jerome; Swennen, Rony; Ann, Jennifer; Rofina Yasmin Othman, Harikrishna
Fusarium wilt of bananas (Musa spp.), caused by Fusarium oxysporum f. sp. cubense (Foc) causes up to 100% yield loss in bananas. Foc race 1 in particular is very devastating to dessert bananas in Uganda. One of the effective control strategies for the disease is the development of resistant cultivars through breeding. The objectives of this study were to identify suitable banana germplasm for generating a segregating population for resistance to Foc race 1 and understand the mode of inheritance of resistance to Foc race 1. Twenty-two banana accessions sourced from the National Agricultural Research Organisation in Uganda were challenged with Foc race 1 in a screen house experiment. Monyet, resistant to Foc race 1 and Kokopo, susceptible, were selected and crossed to generate 142 F1 genotypes. These F1 genotypes were also challenged with Foc race 1 in a screen house experiment. Data were collected on rhizome discoloration index (RDI), leaf symptom index (LSI) and pseudo-stem splitting (PSS), and analysed for variability. The banana accessions evaluated showed varying degrees of resistance to Foc race 1. Segregation ratios for resistant versus susceptible progenies fitted 13:3 (v2 = 0.12, P = 0.73) for RDI and 11:5 (v2 = 3.04, P = 0.08) for PSS. Estimated broad sense heritability was 27.8% for RDI, 13.9% for LSI and 14.7% for PSS. The results suggest that resistance to Foc race 1 in banana is controlled by at least two dominant genes with epistatic interaction and that
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.
Improved Propagation Techniques to Enhance the Productivity of Banana (Musa spp.)
(Open Agriculture, 2018) Tumuhimbise, Robooni; Talengera, David
The objective of this article is to provide information on pertinent propagation techniques for increased banana productivity. Banana, a very important crop in many tropical and subtropical countries of the world, is propagated with extreme difficulties. Its ordinary propagation technique of using suckers directly detached from a mother plant is limited by low multiplication rates and propensity of disseminating pests and diseases, which culminates in reduced banana productivity. Improved propagation techniques such as mother plant stripping, decapitation and mini-corms that increase the number of suckers are also somewhat deficient for large scale seed production and quality. Consequently, tissue and cell culture methods have been developed to address some of the challenges of seed quantity and quality although they are yet to be widely adopted. In this detailed review that includes results from hard-to-find literature, we discuss the traditional and modern methods of banana propagation, their benefits and limitations. Specifically, tissue culture stands out as the most prolific method of delivering high quantity and quality seed in banana. Its applicability, however, is limited by high costs of production and a need for skilled personnel and specialized equipment. It is imperative that to build a sustainable and viable banana seed production system, a multiplication scheme that combines two or more multiplication methods including tissue culture for cleaning the seed stock is utilized. The information provided gives premise for interventions to alleviate the problems of low banana seed availability, quantity and quality.
Molecular Markers and Their Application in Fusarium Wilt Studies in Musa spp.
(Sains Malaysiana, 2019) Kabiita Arinaitwe, Ivan; Teo, Chee How; Kayat, Fatimah; Tumuhimbise, Robooni; Uwimana, Brigitte; Kubiriba, Jerome; Harikrishna, Jennifer Ann; Othman, Yasmin
Bananas and plantains (Musa spp.) are an important socio-economic fruit crop grown worldwide. Their production across the regions where they are grown is largely hampered by pests and diseases. Fusarium wilt is a disastrous diseases of bananas caused by the fungal pathogen Fusarium oxysporum f.sp. cubense (Foc). Managing it with chemicals, biological control agents and cultural methods is ineffective. Host plant resistance is the most effective and durable approach of managing most pest and disease epidemics in most plant species and could equally be effective in managing Fusarium wilt in bananas. Crossbreeding as one of the ways to introgress disease resistance genes and phenotyping for biotic and abiotic stresses currently used in banana breeding is apparently difficult to apply because of banana’s low fertility, gigantic size, and long-life cycle which prolongs its breeding cycle. There is, therefore, a need to apply molecular markers in banana genetic improvement for Fusarium wilt resistance because of their accuracy, speed, robustness and effectiveness of operation. The objective of this article was to review and discuss molecular markers that have been successfully used in studying Fusarium wilt in bananas and some other important crops. Molecular markers discussed in this article include Random Amplified Polymorphic DNA, Sequence Characterized Amplified Region, Simple Sequence Repeat, Inter-Simple Sequence Repeat, and Single Nucleotide Polymorphism. The information discussed in this article informs future decisions to identify suitable marker systems for fine mapping of target regions and accelerated identification of quantitative trait loci for Foc resistance in bananas.
‘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.
New High-yield Cooking Banana Cultivars with Multiple Resistances to Pests and Diseases (‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’) Released in Uganda
(HortScience, 2018) Tumuhimbise, Robooni; Barekye, Alex; Kubiriba, Jerome; Akankwasa, Kenneth; Arinaitwe, Ivan K.
‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’ are secondary triploid cooking banana cultivars. They were bred by the National Agricultural Research Organisation (NARO) in Uganda, and officially released and added to the national cultivar list by the Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) in 2017. The cultivars are highly resistant to black Sigatoka, a fungal disease caused by Mycosphaer- ella fijiensis (Morelet), which was the main breeding target. In addition, they are resistant to the banana weevil Cosmopolites sordidus (Germar) and nematodes, the pests of most economic concern in banana production, especially in the lowland areas of central and eastern Uganda. Compared with the local cultivars, which have an average bunch yield of less than 30% of their potential of 60 to 70 t/ha/year, ‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’ produce average bunch yields of 54.9 t/ha/year, 60.4 t/ha/year, 64.7 t/ha/year, and 68.8 t/ha/year, respectively. Moreover, they have soft, tasty, aromatic, and near-yellow food colors, which make them appreciated like the existing farmer-accustomed local cooking banana cultivars that have, however, a low yield and are susceptible to pests and diseases.
Performance of Narita Banana Hybrids in the Preliminary Yield Trial for Three Cycles in Uganda
(NARO, 2015) Tushemereirwe, Wilberforce; Batte, Michael; Nyine, Moses; Tumuhimbise, Robooni; Barekye, Alex; Ssali, Tendo; Talengera, David; Kubiriba, Jerome; Lorenzen, Jim; Swennen, Rony; Brigitte, Uwimana
Bananas (Musa spp.) are an indispensable part of life in Eastern Africa providing up to one fifth of total calorie consumption per capita. Unlike many staple crops, bananas deliver food throughout the year, making them an ideal crop for household incomes, food and nutrition security. However, banana yields are low due to several factors amongst others pests and diseases: weevils and nematodes, Fusarium wilt, bacterial wilt and black Sigatoka. There are many potential technology-based interventions for increasing banana yields but host plant resistance is the most appropriate and cost effective intervention given the current stage of development of banana systems in the region. Host-plant resistance also offers significant spill over benefits for human health and positive environmental impacts. Therefore, the Ugandan National Agricultural Research Organization (NARO) and the International Institute of Tropical Agriculture (IITA) jointly breed bananas largely for host-plant resistance to improve banana yields. One of the most important current products of their joint banana breeding efforts is secondary triploid hybrids for food and juice herein referred to as NARITA hybrids. This name specifies the contribution of NARO and IITA. An earlier report (NARITA report 1) presented the results of 25 NARITA hybrids for cycles 1 and 2 combined. The current report presents and discusses the results of the same 25 NARITA hybrids (18 for food and seven for juice) evaluated for three crop cycles at Sendusu in central Uganda and analyzed in combined and separate forms. Results of individual NARITA hybrids within cycles showed high degree of variation for the traits assessed, implying a high potential for selection among the NARITA hybrids evaluated. For example, the bunch weight (BWT) of the individual NARITA hybrids ranged from as low as 5 kg for NARITA 19 to as high as 45 kg for NARITA 24 with a mean of 17.8 kg. Averaged across three cycles, BWT ranged from as low as 8.7 kg for NARITA 19 to as a high as 30.4 kg for NARITA 24. Ninety six per cent of the hybrids had a mean BWT greater than the mean of the local check (Mbwazirume) (11.0 kg). Similarly, NARITA hybrids were better than Mbwazirume for most of the other traits assessed. Eighty four per cent of the NARITA hybrids evaluated were better than the best founder parent (NFUUKA) for bunch yield (t ha-1), indicative of the significant breeding progress made by NARO and IITA in this breeding program. This could be confirmed by the positive better founder parent heterosis for BWT recorded by all NARITA hybrids, with NARITA 17, NARITA 18, NARITA 7 (M9), NARITA 21 and NARITA 14 (all food type) exhibiting highest heterosis. Results of combined analysis of variance (ANOVA) showed significant differences among the NARITA hybrids for all the 14 traits assessed including BWT. This indicated the potential for further selection and improvement of the NARITA hybrids for all the 14 traits. Additionally, results of combined ANOVA showed significant differences among three crop cycles for all the traits assessed except days to bunch maturity (DTM) and number of functional leaves at flowering (NFLF), indicating that the selection of banana hybrids could best be done at certain cycle numbers. The performance of NARITA hybrids for most traits was much higher at cycles 2 and 3 than at cycle 1 with the highest performance observed at cycle 3. However, the difference between cycle 2 and cycle 3 was not significantly different for most traits including BWT. The clear implication of this is that selection for banana hybrids should be done at cycle 2 to reduce costs involved in the management of trials since banana trials are always huge considering the size of bananas as well as spacing of 3 x 3 m or 2 x 3 m commonly used. Also, banana performance data analysis should not be based on a combined evaluation of cycle 1 and 2, as was previously done for NARITA report 1, but on an analysis of individual cycles, preferably cycle 2. The limitation of single site and single line plots is acknowledged. Hence, NARITA hybrids will be evaluated in larger and replicated multi-location trials to ascertain their actual performance, adaptability and stability in comparison with the local EAHB cultivars. Nevertheless, based on these preliminary results, potential high yielding banana hybrids combining resistance to black Sigatoka and farmer-preferred quality traits exist within this NARITA population.
Physicochemical analysis of Ugandan tea (Camellia sinensis) germplasm reveals potential commercial green and black tea varieties
(Taylor & Francis, 2023-05) Grace Nalugo, Racheal; Kaweesi, Tadeo; Kawooya, Ronald; Nuwamanya, Ephraim; Mugisa, Charles; Namutebi, Vivian; Tumwine, Venansio; Turyahebwa, Vereriano; Tumuhimbise, Robooni
Tea (Camellia sinensis L.) is an important beverage consumed worldwide. In Uganda, it is the second-largest and highly priori-tized export crop after coffee and provides the much-needed jobs to more than 800,000 people. Despite its importance in the coun-try, the crop has received very limited research attention for its improvement and optimal utilization. This study was aimed at characterizing existing tea germplasm in Uganda to inform future breeding initiatives for market-preferred tea varieties. Fifty-eight advanced tea clones were randomly selected from the tea germ-plasm conserved at Uganda’s Tea Research Center in Rwebitaba and analyzed in the laboratory for eight physicochemical descrip-tors. Hierarchical cluster analysis performed on the 58 clones using Cluster-R package revealed four main clusters, indicating the exis-tence of variation for physicochemical parameters within tested germplasm. This variation can be exploited to select among and/or improve the studied germplasm genetically for quality. High fer-mentation rate, which is one of the key indicators for good-quality black teas, revealed 15 fast-fermenter tea clones. Clone “UTR12/12” was identified as the most rapid fermenter, fully fermenting within 30 min, which implies a good clone for black tea. The clone also had the highest polyphenol content (26.7%), higher than the high- quality clone “UTR6/8” (control). Other tea clones whose polyphe-nol content was within the range of the control black tea clone were: “UTR144/10” (20.9%) and ‘UTR144/17, (20.66%). The identi-fied promising black tea clones can be advanced to multi-location trials for further evaluation and selection for eventual variety release as commercial black-tea clones.
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.
Seed Set Patterns in East African Cooking Bananas (Musa spp.) are Dependent on Weather Before, During, and After Pollination
(Research Square, 2020) Waniale, Allan; Mukasa, Settumba B.; Tugume, Arthur K.; Tumuhimbise, Robooni; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Batte, Michael; Brown, Allan; Swennen, Rony
Seed set in banana (Musa spp.) is influenced by weather but the most critical weather attribute(s) and the critical period are unknown. Such information is of paramount importance to increase seed set for banana breeding programs. Three female fertile East African cooking bananas (EACBs), ‘Enzirabahima’ (AAA), ‘Mshale’ (AA), and ‘Nshonowa’ (AA) were pollinated with the highly male fertile wild banana ‘Calcutta 4’ (AA). At full maturity, bunches were harvested and ripened and seeds extracted from ripe fruit pulp. Seed set was then correlated with weather before, during, and after pollination. Results: Seed set was positively correlated with high temperatures (r=0.172 – 0.488), solar radiation (r=0.181 – 0.282) and negatively correlated with rainfall (r=-0.214 – -0.238) and relative humidity (RH) (r=-0.158 – -0.438) between 75 and 15 days before pollination (DBP). The pattern of weather association was cultivar-dependent with ‘Nshonowa’ having the strongest significant associations. At the time of pollination, high average temperatures were critical for seed set in ‘Enzirabahima’ (r=0.214, P<0.01) while high morning RH was critical for ‘Mshale’ (r=0.299, P<0.01). After pollination, high morning temperatures were associated with seed set (r=0.150 – 0.429) between 15 days to 90 days after pollination (DAP). High average temperatures were negatively correlated with seed set in ‘Mshale’ and ‘Nshonowa’ from 45 DAP to time of harvest (r=-0.208 – -0.344). Coefficients of correlation were generally highest 15 DBP especially for ‘Mshale’ and ‘Nshonowa.’ Principle component analysis showed that average and maximum temperature are the most important variables in the entire data set. Conclusion: Coefficients of correlation were generally less than 0.5 partly as a result of weather involvement in seed set at several floral development stages; before, during, and after pollination. The most critical developmental stage is 15 DBP especially for ‘Mshale’ and ‘Nshonowa’ as they had the high correlation coefficients. Average temperature should be the main focus for seed set increase in banana.
Seed Set Patterns in East African Cooking Bananas are Asymmetric in Bunches and Fruits
(Research Square, 2020) Waniale, Allan; Mukasa, Settumba B.; Tugume, Arthur K.; Tumuhimbise, Robooni; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Batte, Michael; Brown, Allan; Swennen, Rony
Low female fertility in bananas is the biggest hurdle for banana breeding. The aim of this study was to determine seed set patterns in East African cooking bananas EACBs to inform future decisions on a more targeted approach of increasing seed set and subsequently banana breeding efficiency. Matooke (AAA) and Mchare (AA) bananas are genetically distinct but belong to the same genetic complex, they referred to as EACBs. Seed set patterns in ‘Enzirabahima’ (AAA), ‘Mshale’ (AA) and ‘Nshonowa’ (AA) all with residual fertility were examined after hand pollination with a highly male fertile wild banana ‘Calcutta 4’ (AA). Results: Seed set in ‘Enzirabahima’ is predominant in distal hands. Mchare cultivars have a slightly more even distribution of seeds in their hands compared to ‘Enzirabahima.’ There is a gradual increase in seed set from proximal to distal hands with a slight drop in the last hand. This pattern is more definite in ‘Enzirabahima’ and ‘Mshale’ while ‘Nshonowa’ has a somewhat inconsistent pattern. There is also a drop in seed set per 100 fruits per hand from small to larger bunches. However, larger bunches have a higher pollination success compared to smaller bunches. They therefor set more seed on 100 fruits per hand and per bunch basis if bunches without seed are accounted for. Pollination success rate increases from smaller to larger bunches of EACBs. Seed set is biased toward the distal third part of fruits of examined EACBs as well tetraploid Matooke hybrid ‘401K-1’ (AAAA) and improved diploid ‘Zebrina’ GF (AA) that were used for comparison. In comparison, in the highly female fertile ‘Calcutta 4,’ seed set is along the entire length of the fruit. Conclusion: Seed set bias in the distal hands and distal end of fruits suggests a systematic mechanism rather than a random occurrence. It is expected that this information will provide a foundation for increased crossbreeding efficiency in bananas.

Browsing by Author "Tumuhimbise, Robooni"

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