Browsing by Author "Namanya, Priver"
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Item Allometric relationships and carbon content for biomass-carbon estimation of East African Highland Bananas (Musa spp. AAA-EAHB) cv. Kibuzi, Nakitembe, Enyeru and Nakinyika(African Journal of Agricultural Research, 2018) Kamusingize, Daphine; Mwanjalolo Majaliwa, Jackson; Komutunga, Everline; Tumwebaze, Susan; Nowakunda, Kephas; Namanya, Priver; Kubiriba, JeromeGlobally, 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 cultivarspecific 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.Item Biofortified East African Highland Bananas to Alleviate Vitamin A Deficiency in Uganda(Gates Open Res, 2019) Buah, Stephen; Tindamanyire, Jimmy M.; Namanya, Priver; Kubiriba, Jerome; Paul, Jean-Yves; Dale, James L.; Tushemereirwe, WilberforceMicronutrient deficiency, also referred to as hidden hunger, is a global public health problem that affects over two billion people (Tulchinsky, 2010). In Uganda, micronutrient deficiency is the third most important public health problem after HIV/AIDS and malaria. Vitamin A deficiency (VAD) and Iron Deficiency Anaemia (IDA) are the major causes of anaemia in Uganda. VAD affects 20-35% of children below five years of age and the same proportion of women of child-bearing age. The aim of the Banana 21 project is to alleviate vitamin A deficiency through biofortification of Uganda’s major staple food, banana.Item Carbon sequestration potential of East African Highland Banana cultivars (Musa spp. AAA-EAHB) cv. Kibuzi, Nakitembe, Enyeru and Nakinyika in Uganda(Journal of Soil Science and Environmental Management, 2017) Kamusingize, Daphine; Mwanjalolo Majaliwa, Jackson; Komutunga, Everline; Tumwebaze, Susan; Nowakunda, Kephas; Namanya, Priver; Kubiriba, JeromeDespite the global interest to increase the world's carbon stocks, most carbon sequestration strategies have largely depended on woody ecosystems whose production is threatened by the continuous shortage of land, hence the need to explore viable alternatives. The potential of bananas to sequester carbon has been reported but there is limited knowledge on the performance of various cultivars as specific carbon stocks are often lost in global assessments. Therefore, this study aimed at exploring the potential of and variability in carbon stocks of selected East African Highland Banana (EAHB) cultivars. Plant and soil data were collected using destructive and non-destructive techniques in 30×30m2 sampling plots for 4 cultivars Kibuzi, Nakitembe, Enyeru and Nakinyika growing in two agroecological zones of Uganda being the L.Victoria Crescent and the South-western region. Total carbon and Soil Organic Carbon (SOC) stocks did not differ considerably across cultivars (P>0.05). However, there was significant variation (P<0.05) in plant carbon stock being lowest in two cultivars: Nakinyika at 0.37±0.19 Mgha-1 and Nakitembe at 0.40±0.19Mgha-1; and highest in Enyeru at 1.64±0.18 Mgha-1. The SOC stock variation difference across depth was 2.9-8.5 Mgha-1 being higher in top soil than sub-soil. Despite the small plant carbon stock amounts, the system enables much more carbon to be stored in the soil considering the proportion of what is contained in the plant to that in the soil across all cultivars (0.4-2%). The study therefore recommends revision of existing carbon frameworks to incorporate the contribution of non-woody perennials like bananas in the carbon cycle so that the poor small scale farmers who cannot afford large acreages to establish tree plantations can also benefit from such initiatives.Item Genotypic variability estimates of agronomic traits in secondary triploid banana ‘Matooke’ (Musa sp., AAAEA) hybrids(African Journal of Plant Science, 2016) Tendo Ssali, Reuben; Barekye, Alex; Buregeya, Henry; Erima, Rockefeller; Namanya, Priver; Kubiriba, JeromeEffective selection of hybrids for a trait is based on the extent of variation and heritability. This study examined yield parameters of secondary triploid ‘Matooke’ hybrids and the extent of their genetic diversity based on the traits evaluated. Eleven genotypes, including nine ‘Matooke’ hybrids and two landraces were evaluated for 12 characters in a preliminary yield trial (PYT) over three crop cycles. Plant height, bunch weight, number of standing leaves at flowering and the youngest leaf spotted with black Sigatoka symptoms showed significant interaction between genotype and crop cycle. While characters such as pseudo stem girth, number of days for fruit filling, number of hands, number of fingers on the second hand and the fruit length showed stable differences amongst these genotypes. The genotypic coefficient of variation for the characters ranged from 7.6% (finger length) to 33.5% (bunch weight); with moderate heritability estimates varying from 13.5% (pseudostem girth) to 67% (plant height). Bunch weight showed strong positive correlation with number of hands, number of fingers on the second hand, the fruit length and pseudostem girth. These results imply that breeders could select for some of these variable and ratoon stable traits in a single cycle of early evaluation trial, subsequently reducing costs, time and space in field testing.Item Golden bananas in the field: elevated fruit pro-vitamin A from the expression of a single banana transgene(Plant Biotechnology Journal, 2017) Jean-Yves, Paul; Harjeet, Khanna; Kleidon, Jennifer; Hoang, Phuong; Geijskes, Jason; Daniells, Jeff; Zaplin, Ella; Rosenberg, Yvonne; James, Anthony; Bulukani, Mlalazi; Pradeep, Deo; Arinaitwe, Geofrey; Namanya, Priver; Becker, Douglas; Tindamanyire, James; Tushemereirwe, Wilberforce; Harding, Robert; Dale, JamesVitamin A deficiency remains one of the world's major public health problems despite food fortification and supplements strategies. Biofortification of staple crops with enhanced levels of pro-vitamin A (PVA) offers a sustainable alternative strategy to both food fortification and supplementation. As a proof of concept, PVA-biofortified transgenic Cavendish bananas were generated and field trialed in Australia with the aim of achieving a target level of 20 μg/g of dry weight (dw) β-carotene equivalent (β-CE) in the fruit. Expression of a Fe'i banana-derived phytoene synthase 2a (MtPsy2a) gene resulted in the generation of lines with PVA levels exceeding the target level with one line reaching 55 μg/g dw β-CE. Expression of the maize phytoene synthase 1 (ZmPsy1) gene, used to develop ‘Golden Rice 2’, also resulted in increased fruit PVA levels although many lines displayed undesirable phenotypes. Constitutive expression of either transgene with the maize polyubiquitin promoter increased PVA accumulation from the earliest stage of fruit development. In contrast, PVA accumulation was restricted to the late stages of fruit development when either the banana 1-aminocyclopropane-1-carboxylate oxidase or the expansin 1 promoters were used to drive the same transgenes. Wild-type plants with the longest fruit development time had also the highest fruit PVA concentrations. The results from this study suggest that early activation of the rate-limiting enzyme in the carotenoid biosynthetic pathway and extended fruit maturation time are essential factors to achieve optimal PVA concentrations in banana fruit.Item 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, PatrickInformation 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.Item ‘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.Item Physical Effectiveness of Soil and Water Conservation Technologies in Drought Prone Areas of Western and Central Uganda(Journal of Agricultural Science and Technology, 2015) Komutunga, Everline; Tushemereirwe, Wilberforce; Kubiriba, Jerome; Namanya, Priver; Oratungye, Kevin John; Akodi, David; Agaba, Choice; Ahumuza, Elizabeth; Kamusingize, DaphineThe effect of soil and water conservation (SWC) practices on controlling surface runoff and soil loss was studied in drought prone banana growing areas of Uganda, during the two major rainy seasons of 2014. The study was conducted at two sites— Ntungamo (Southwest) and Sembabule (Central), with comparable slopes of about 13%-25%. The treatments included mulch, manure, manure + mulch and a control with no conservation. Results indicated that conservation practices of mulch and manure + mulch significantly reduced surface runoff and soil loss by about 72%-85%, when compared to farmers’ up-and-down cultivation practice (control). It was also observed that significantly greater amounts of soil loss occurred from manure and control plots than the ones with mulch. Thus, the combination of manure and mulch is recommended for uptake by crop farmers in the study areas, if they are to overcome drought stress and adapt to changes in climate. More research is needed to quantify nutrient losses resulting from runoff under the different SWC techniques. Modeling such effects is essential in assessing the impacts of SWC practices on soil and crop productivity.Item 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, EldadBanana 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.Item Reproductive efficiency and breeding potential of East African highland (Musa AAA-EA) bananas(Field Crops Research, 2006) Ssebuliba, Ruth; Talengera, David; Makumbi, Dan; Namanya, Priver; Tenkouano, Abdou; Tushemereirwe, W.; Pillay, MichaelThe East African highland banana (Musa spp. AAA) is an economically important food crop. The crop is affected by a number of diseases and pests. Genetic improvement of the crop is hindered by very low seed set and poor seed germination. The objective of this study was to compare seed set, seed quality and embryo rescue rates of hybrid seeds obtained from 20 East African highland banana cultivars crossed with a fertile diploid species, Musa acuminata spp. burmannicoides ‘Calcutta 4’, as a male parent. There was great variation in seed set, seed quality and in vitro embryo germination rates among the cultivars. Although 72% (range = 47–88%) of the seeds appeared normal externally characterized by black hard integuments, only 59% (range = 35–81%) contained embryos, of which 9% (range = 0–22%) germinated. This study demonstrated that hard-seededness alone does not signify the presence of an embryo and should not be regarded as a measure of seed fertility in East African highland bananas. Cultivars ‘Entukura’, ‘Enzirabahima’ and ‘Kabucuragye’ of the ‘Nfuuka’ clone set were superior in terms of seed set, presence of seeds with embryos and culturability of embryos. These cultivars are recommended as female parents for a crossing program in the improvement of East African highland bananas. The low embryo rescue rates suggest that hybrid seeds derived from East African highland banana possess factors that cause high embryo abortion. This may be ascribed to endosperm breakdown, which can release toxins.Item 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, EldadIt 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.Item Variation and Abundance of Resistant Starch in Selected Banana Cultivars in Uganda(Cross Ref, 2024-09) Kajubi, Ali; Baingana, Rhona; Matovu, Moses; Katwaza, Ronald; Kubiriba, Jerome; Namanya, PriverThe physiochemical, structural, and molecular characteristics of starch influence its functional properties, thereby dictating its utilization. The study aimed to profile the properties and quantity of resistant starch (RS) from 15 different banana varieties, extracted using a combination of alkaline and enzyme treatments. Granular structure and molecular organization were analyzed using light microscopy, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The physiochemical and functional properties were also investigated. RS content ranged from 49% to 80% without significant relationship to amylose (AM) (r = −0.1062). SEM revealed significant microarchitectural differences on the granules potentially affecting granule digestibility. FTIR and chemometrics identified differences in the crystalline peaks, yielding varying degrees of the molecular order of the RS polymers that aid in differentiating the RS sources. Despite similar solubility and swelling profiles, the pasting profiles varied across varieties, indicating high paste stability in hydrothermal processing. Clarity ranged from 43% to 93%, attributed to amylose leaching. This study highlights that RS from bananas varies in quantity, structure, and functionality, necessitating individualized approaches for processing and utilization.