Browsing by Author "Odong, Thomas L."
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Item Assessment of Groundnut (Arachis hypogaea L.) Genotypes for Yield and Resistance to Late Leaf Spot and Rosette Diseases(Journal of Experimental Agriculture International, 2018) Elsiddig Mohammed, Khalid; Afutu, Emmanuel; Odong, Thomas L.; Okello, David K.; Nuwamanya, Ephraim; Grigon, Olupot; Rubaihayo, Patrick R.; Okori, PatrickGroundnut which is a major staple food crop in Uganda is constrained by late leaf spot (LLS) and groundnut rosette disease (GRD), accounting for major economic yield loss. This study was conducted to identify sources of resistance to LLS and GRD and yield potential of selected groundnut genotypes that could be used in breeding programs. Thirty-eight groundnut genotypes were evaluated at the National Semi Arid Resources Research Institute (NaSARRI)-Serere, Eastern Uganda during the first and second seasons of 2015. The experiment was arranged in randomized complete block design with four replications. The results showed highly significant (P < 0.01) genotype-by-season interaction for most of the traits studied. There were significant differences among the genotypes for 100 seed weight (P < 0.01), and dry pod yield and unshelled sample of 100 pods at P < 0.05. Late leaf spot severity (at harvest), GRD incidence (at 12 weeks) and severity (at harvest) were significantly (P < .01) different and positively correlated with Area Under Disease Progress Curve (AUDPC). GRD severity at harvest showed highly significant (P < 0.001) negative correlation with shelling percentage. Both 100 seed weight and unshelled sample of 100 pod showed highly significant (P < 0.01) negative correlations with LLS at harvest, LLS AUDPC, GRD at 12 weeks, GRD AUDPC, and GRD severity. Genotypes susceptible to both LLS and GRD recorded the lowest 100 seed weight. Nine genotypes (Serenut.2, SGV 0001, SGV 0005, SGV 0006, SGV 0019, SGV 0071, SGV 0082, SGV 0083, and SGV 89751T) showed resistance to both diseases with high yield potential. These genotypes could be used to introgress resistance to both diseases in acceptable cultivars which are susceptible.Item Assessment of Staking in a Climbing Bean Production System as Practiced by Smallholder Farmers in Uganda(World Science Research Journals, 2017) Takusewanya, Rose; Namayanja, Annet; Bwogi, Godfrey Vianney; Mwine, Julius; Odong, Thomas L.Adoption of climbing bean production in Eastern Africa is faced with the challenge of finding suitable staking materials which is prerequisite for high yield potential. The objective of this study was to contribute to understanding the trends in staking and staking requirements in climbing bean production and the related ecological management practices in the Ugandan highland agro-ecosystem. Sampling was done using a four-stage sampling procedure, based on 150 households selected randomly each in Kabale and Kisoro districts. Results revealed that long term maturing trees such as eucalyptus were the most commonly used types of stakes (92.7%) in Kabale. On the other hand in Kisoro, it was stems of elephant grass (62%) followed by long term maturing trees (50.6%), shrubs mainly vernonia (30%) and maize plant, maize and sorghum Stover (22%). The study revealed several challenges smallholders faced with stakes and staking such as costly stakes, breaking of stakes due to heavy pod load or becoming old, theft, multiple uses of stakes (fire wood, building), termites and the cumbersome activities (cutting, transporting). However, some farmers have not perceived staking as a problem and have developed some initiatives to cope with the shortage. Further research on the sources of stakes is recommended.Item Division of labour in nakati (Solanum aethiopicum) production in central Uganda(African Journal of Agricultural Research, 2008) Ssekabembe, Charles K.; Odong, Thomas L.Nakati (Solanum aethiopicum) production is labour intensive. This paper reports on the division of labour in the production of this crop in central Uganda. There is significant division of labour between husbands and wives. Heavy duty land preparation is mostly done by husbands and hired male labour in order to do it fast when large acreages of Nakati are involved. Hired labour (35%) does most of the land preparation and weeding. Women do hand weeding better than men. Sowing is predominantly done by men (50%) who claim better experience than the females in broadcasting the crop. Pest control is mostly done by husbands and hired male labour (78%). Most women can not carry the knapsack sprayer and are often busy with household work. Fertilizer application is also mostly done by men (56%). Harvesting is mostly done by family labour (42%), and mostly by males who can carry the heavy Nakati bundles from the fields. Marketing is predominantly done by husbands (87%). Sometimes wives opt to have a separate plot of Nakati to cater for their unique needs. Generally, men do most of the work in Nakati production but training for Nakati improvement ought to target both men and women. Women should be organized into groups which can also be voluntarily joined by husbands, and these groups can be easily trained by extensions agents. It is preferable for women extensions agents to train the women farmers’ groups because women are likely to relate to fellow women in this regard. Since women are usually busy with household work training should coincide with the dry season when there is less work in the field. Farmer field schools could also benefit Nakati growers.Item Gender and the conservation of traditional crop varieties: the case of traditional sorghum in Agago District, Uganda(AgriGender Journal of Gender, Agriculture and Food Security, 2020) Busingey, Martha; Odong, Thomas L.; Miiroy, RichardThis study examines the roles men and women play in the cultivation, processing, and marketing of traditional sorghum varieties and gendered trait preferences as they relate to the continued existence of these varieties in Agago District. The study utilized primary data which was collected through a survey and focus group discussions. The results suggest that continued production and utilization of traditional sorghum is a result of the efforts of both men and women, although the general labor burden fell on women. There was a differential preference for the traditional sorghum characteristics of market, taste, storage, threshing, and milling by gender. Technology advancements in processing ease women's time constraints and could result in the conservation of di cult-to-process varieties that otherwise possess good traits. Lastly, a gender dimension should be included in future strategies to understand the conservation of varieties as well as the adoption of improved sorghums.Item Genetic Diversity and Population Structure Analysis of Tropical Soybean (Glycine Max (L.) Merrill) using single Nucleotide Polymorphic Markers(Global Journal of Science Frontier Research, 2020) Obua, Tonny; Sserumaga, Julius P.; Opiyo, Stephen O.; Tukamuhabwa, Phinehas; Odong, Thomas L.; Mutuku, Josiah; Yao, NasserSoybean (Glycine max (L.) Merrill) is among the most important crops worldwide due to its numerous uses in feed, food, biofuel, and significant atmospheric nitrogen fixation capability. To understand the genetic diversity and population structure of tropical soybean germplasm, 89 genotypes from diverse sources were analyzed using 7,962 SNP markers. The AMOVA results showed low diversity among and high within the populations, while the polymorphism information content (PIC) was 0.27. Both phylogenetic and principal component analysis grouped the 89 soybean genotypes into three major clusters, while population structure grouped the soybean genotypes into two subpopulations. On the other, the average Roger genetic distances within the study population was 0.34. The low diversity reported in the studied soybean germplasm pool is particularly worrying, considering the new trends of climate change and the emergence of new pests and diseases of soybean. Therefore, in order to address these challenges and develop soybean varieties with desirable traits, there is a need to broaden the genetic base of tropical soybean through the importation of germplasm from other countries.Item Genome-wide association study identified candidate genes controlling continuous storage root formation and bulking in hexaploid sweetpotato(BMC plant biology, 2020) Bararyenya, Astère; Olukolu, Bode A.; Tukamuhabwa, Phinehas; Grüneberg, Wolfgang J.; Ekaya, Wellington; Low, Jan; Ochwo-Ssemakula, Mildred; Odong, Thomas L.; Talwana, Herbert; Badji, Arfang; Kyalo, Martina; Nasser, Yao; Gemenet, Dorcus; Kitavi, Mercy; Mwanga, Robert O. M.Continuous storage root formation and bulking (CSRFAB) in sweetpotato is an important trait from agronomic and biological perspectives. Information about the molecular mechanisms underlying CSRFAB traits is lacking. Results: Here, as a first step toward understanding the genetic basis of CSRFAB in sweetpotato, we performed a genome-wide association study (GWAS) using phenotypic data from four distinct developmental stages and 33,068 single nucleotide polymorphism (SNP) and insertion-deletion (indel) markers. Based on Bonferroni threshold (pvalue < 5 × 10− 7), we identified 34 unique SNPs that were significantly associated with the complex trait of CSRFAB at 150 days after planting (DAP) and seven unique SNPs associated with discontinuous storage root formation and bulking (DCSRFAB) at 90 DAP. Importantly, most of the loci associated with these identified SNPs were located within genomic regions (using Ipomoea trifida reference genome) previously reported for quantitative trait loci (QTL) controlling similar traits. Based on these trait-associated SNPs, 12 and seven candidate genes were respectively annotated for CSRFAB and DCSRFAB traits. Congruent with the contrasting and inverse relationship between discontinuous and continuous storage root formation and bulking, a DCSRFAB-associated candidate gene regulates redox signaling, involved in auxin-mediated lateral root formation, while CSRFAB is enriched for genes controlling growth and senescence. Conclusion: Candidate genes identified in this study have potential roles in cell wall remodeling, plant growth, senescence, stress, root development and redox signaling. These findings provide valuable insights into understanding the functional networks to develop strategies for sweetpotato yield improvement. The markers as well as candidate genes identified in this pioneering research for CSRFAB provide important genomic resources for sweetpotato and other root crops.Item Genotype by environment effects on promiscuous nodulation in soybean (Glycine max L. Merrill)(Agriculture & Food Security, 2017) Agoyi, Eric E.; Odong, Thomas L.; Tumuhairwe, John B.; Chigeza, Godfree; Diers, Brian W.; Tukamuhabwa, PhinehasUnderstanding factors influencing the expression of a trait is key in designing a breeding program. Genotype by environment interaction has great influence on most quantitative traits. Promiscuous nodulation is a trait of importance for soybean production in Africa, because of the soil bacteria Bradyrhizobium japonicum not being indigenous in most African soils. Most soybean cultivars require B. japonicum for nodulation leading to the need for seed inoculation before sowing soybean in Africa. Few cultivars have capability to nodulate with Bradyrhizobia spp. that are different from B. japonicum and native in African soils. Such cultivars are termed “promiscuous cultivars.” Field experiments were conducted in six locations in Uganda for two seasons, to investigate the extent of environmental influences on the nodulation ability of promiscuous soybean genotypes. Results: Additive main effect and multiplicative interaction effects showed highly significant environment and genotype by environment (G × E) interaction effects on all nodulation traits. G × E interaction contributed more to the total variation than genotypes. The genotypes Kabanyolo I and WonderSoya were the most stable for nodules’ dry weight (NDW), which is the nodulation trait the most correlated with grain yield. Genotype UG5 was the most stable for nodules’ number (NN), and Nam II for nodules’ effectiveness (NE). The genotype NamSoy 4M had the highest performance for NN, NFW, and NDW, but was less stable. WonderSoya had the highest NE. Genotype and genotype by environment analysis grouped environments into mega-environments (MEs), and four MEs were observed for NDW, with NamSoy 4M the winning genotype in the largest ME, and Kasese B the ideal environment for that nodulation trait. Conclusion: This study provides information that can guide breeding strategies. The low genetic effect that led to high environmental and G × E interaction effects raised the need for multi-environments testing before cultivar selection and recommendation. The study revealed genotypes that are stable and others that are high performing for nodulation traits, and which can be used as parental lines in breeding programs.Item Local knowledge, identification and selection of shea tree (Vitellaria paradoxa) ethnovarieties for pre-breeding in Uganda(The Journal of Agriculture and Natural Resources Sciences, 2020) Odoi, Juventine Boaz; Muchugi, Alice; Akias Okia, Clement; Gwali, Samson; Odong, Thomas L.Local knowledge is important in characterizing and selecting shea tree ethnovarieties since the local communities have lived with the species for quite so long. The communities have developed their classification methods based on specific phenotypic traits used to distinguish one ethnovariety from another. This has helped them select and conserve specific genotypes of their interest on farm. Variants of shea trees exist in different populations known by the local communities. This study aimed at identifying and selecting high oil yielding shea tree “ethnovarieties” in Katakwi; Otuke; Amuru; Moyo; Arua and Nakasongola districts of Uganda using local knowledge. The districts were selected because of their long historical association with shea trees which has become part of their socio-cultural and economic lifestyle, so they have broad local knowledge about shea tree variations within their areas. The study aimed at identifying and selecting superior individual shea tree ethnovarieties with high oil yield using local knowledge for seed collection to raise a half sib population. Data was collected in the months of November and December 2017 from 246 shea tree farmers through interviews, 8 focus group discussions conducted, and 6 Key informer interviews with opinion leaders, civic leaders and local leaders in the districts. List of fifteen shea butter tree ethnovarieties with their descriptive characteristics was generated per district. 53.4% of the people who were interviewed were women and 46.4% were men. Data analysis using Statistical Package for Social Sciences (SPSS 20v) was run using multivariate analysis and multiple regression analysis to test for any differences in local knowledge of shea tree ethnovarietis. Differences in local knowledge in the research districts was moderately significant with P = 0.043, df = 4 and X2 =9.837.Item Mode of inheritance of promiscuous nodulation and combining abilities in soybean genotypes(International Journal of Agronomy and Agricultural Research (IJAAR), 2016) Agoyi, Eric E.; Mohammed, Khalid E.; Odong, Thomas L.; Tumuhairwe, John B.; Chigeza, Godfree; Tukamuhabwa, PhinehasKnowledge of the mode of inheritance of a trait can be a powerful decision-making tool in a breeding program, as it helps predicting selection gain, defining breeding strategy and choosing parental lines. This study aimed at estimating genetic parameters to infer the mode of inheritance of promiscuous nodulation in soybean. Half diallel crosses were made among nine parental lines. F2 progenies were field evaluated together with parents for nodulation characteristics and grain yield in response to Bradyrhizobium sp. strain USDA 3456. Data on nodule number (NN), percent of effective nodules (NE), fresh and dry weight of nodules (NFW and NDW), and grain yield were subjected to analysis of variance, and progenies’ means regression against parents’ was performed following Griffing’s Method2/Model 1. General and specific combining abilities, broad and narrow sense heritabilities, and Baker’s ratio were estimated. The study showed predominant GCA effect for all measured traits except NE. Broad and narrow sense heritabilities were high for grain yield and NDW, moderate for NN and NFW, and low for NE. Baker’s ratio was high for all measured traits except for NE. Overall, additive gene action was more important for all measured traits, except NE where non-additive gene action was more important. The high to moderate heritabilities for most traits showed that substantial gain can be achieved through selection.Item Multi-Environmental Evaluation of Protein Content and Yield Stability among Tropical Soybean Genotypes Using GGE Biplot Analysis(Agronomy, 2021) Obua, Tonny; Sserumaga, Julius Pyton; Awio, Bruno; Nganga, Fredrick; Odong, Thomas L.; Tukamuhabwa, Phinehas; Tusiime, Geoffrey; Mukasa, Settumba B.; Nabasirye, MargaretThe yield and protein performance in a soybean genotype result from its interaction with the prevailing environmental conditions. This makes selecting the best genotypes under varied target production environments more complex. This study’s objectives were to determine protein content and protein stability of 30 elite soybean genotypes in major soybean-growing areas of Uganda, assess the yield performance and stability in soybeans and determine the relationship between the protein content and grain yield in soybeans. The genotypes were planted in a randomized complete block design of three replications for six seasons across eight locations in Uganda. Genotype and genotypeby- environment (GGE) biplot analyses classified the test locations into three mega-environments for soybean protein and grain yields. Genotype NII X GC 20.3 had the highest mean protein content of 43.0%, and BSPS 48A-9-2 and BSPS 48A-28 were superior for the mean grain yield (1207 kg ha1). Bulindi was the most discriminating and representative test environment for soybean yield. A weak and negative correlation (r = 0.1**, d.f. = 29) was detected between the protein content (%) and yield (kg ha1). The highest-yielding genotypes BSPS 48A-9-2, BSPS 48A-31, and Nam II GC 44.2 are recommended for further evaluation under farmers’ production conditions for selection and release as new soybean varieties in Uganda.Item Nutrient Profiling of Tropical Soybean (Glycine Max) Core Collection(Global Journal of Science Frontier Research, 2020) Obua, Tonny; Sserumaga, Julius P.; Nganga, Fredrick; Tukamuhabwa, Phineas; Odong, Thomas L.; Mutuku, Josiah; Yao, NasserSoybean (Glycine max (L.) Merrill) is a highly nutritious legume with enormous potential to improve dietary quality for humans and livestock. However, the development of varieties with improved nutritional traits has been affected by the negative correlation that exists among the different traits and the high cost of the phenotypic assessment. The objectives of this study were: (1) to quantify the total protein, total oil and fatty acids of 52 soybean genotypes from different sources, (2) to identify correlations among total protein, total oil content and fatty acids. The total protein content was determined using the Modified Folin-Lowry Method. In contrast, the total oil and fatty acids methyl esters were determined using the chloroform/methanol gravimetric method and Gas Chromatography–Mass Spectrometry. The analysis of variance revealed that the studied traits varied significantly depending on genotypes and origin.Item Prediction of candidate genes associated with resistance to soybean rust (Phakopsora pachyrhizi) in line UG-5(Plant Breed, 2020) Gebremedhn, Hailay M.; Msiska, Ulemu M.; Weldekidan, Miesho B.; Odong, Thomas L.; Rubaihayo, Patrick; Tukamuhabwa, PhinehasOnline databases containing genetic information are crucial to extract new candidate genes from existing data and web-based resources. The objective of this study was, therefore, to predict putative candidate genes associated with resistance to SBR in line UG-5 and understand their functions using different bioinformatics tools from the online available databases. The physical positions for the flanking markers of the identified putative QTLs were searched on the SoyBase database genome browser based on Glyma 1.01 assembly. The putative candidate genes and annotated functions of the surrounding genes were discovered in the vicinity using SoyBase and Phytozome databases. A total of 18 putative candidate genes were predicted on approximately 482.7 kb region of QTL-3 (chromosome 18), among which, six putative candidate genes were found to encode leucine-rich repeat (LRR), Ser/Thr protein phosphatase, leucine-rich repeat receptor-like protein kinase (LRR-RLK) and chitinase- related proteins, which are associated with plant defence signalling pathways. Moreover, F-box and leucine-rich repeat, glycosyltransferase family member and serine/threonine-protein phosphatase 2A catalytic subunit coding genes were predicted on the novel putative QTL detected on chromosome 9. This information could, therefore, be used for further prediction and annotation of candidate genes from sequenced regions of line UG-5 as these putative candidate genes were predicted from the Glyma 1.01 assembly.Item Variation in phenotypic traits of high oil yielding and early maturing shea trees (Vitellaria paradoxa) selected using local knowledge(The Journal of Agriculture and Natural Resources Sciences, 2020) Boaz Odoi, Juventine; Odong, Thomas L.; Akias Okia, Clement; Muchugi, Alice; Gwali, SamsonShea trees (vitellaria paradoxa) grow in West Nile, Teso, Lango and Acholi subregions of Uganda existing in different forms called enthnovarieties. Farmers from each of these subregions use phenotypic characteristics to differentiate one ethnovariety from the other. We conducted phenotypic characterization of shea trees identified by farmers as high oil yielding and early maturing and verified the farmers’ descriptors with standard phenotypic characterization. The study was conducted in the districts of Amuru, Arua, Katakwi, Moyo and Otuke between May and June 2017. One hundred eighty mature shea trees were purposively sampled from the five districts based on local knowledge. Descriptive statistics was then used to determine the variation among the different shea tree phenotypes characterized using standard descriptors. Twenty-seven ethnovarieties were recorded using farmers’ descriptors which were later on reduced to sixteen phenotypic traits using standard phenotypic descriptors related to fruit shapes, texture and kernel color. Variation in the kernel weights, fruit length and fruit width were significant (p < 0.05) and the shea fruit and seed width were highly correlated (78.6%) to their weights. We identified significant variation in shea trees within sites and fruit and seed weights between sites (p ≤ 0.001). Although variability within sites was significant, most parameters (height, diameter at breast height (dbh at 1.3 m), crown shape and height at first branching) were not. Shea fruit/kernel traits are important in characterizing varieties since they exhibit different forms across the sites since tree phenotypic attributes do not vary from location to location in Uganda. This lack of variability of ethnovarieties across the shea belt in Uganda is important in breeding for traits that can be acceptable by all the communities within the shea growing regions. The different shea ethnovarieties are therefore important in influencing policy decisions on their conservation.Item Variation in Seedling Germination and Growth in Five Populations Of vitellariaparadoxa C.F. Gaertn.subsp. Nilotica: A Threatened useful fruit Tree Species in Uganda(Research Square, 2020) Boaz Odoi, Juventine; Odong, Thomas L.; Akias Okia, Clement; Lomoris Okullo, JohnBosco; Okao, Moses; Kabasindi, Harriet; Muchugi, Alice; Gwali, SamsonWe studied seedlings germination and growth performance in an economically and socially important fruit tree species of Vitellaria paradoxaC.F. Gaertn.subsp. nilotica (Kotschy) in Uganda. The study aimed at determining variability in germination of the five shea tree seed lots and seedlings growth performance based on their growth traits. Five populations were considered from four agroecological zones of Uganda and 180 candidates plus trees (16 ethnovarieties) selected as seed trees based on their traits for faster growth and high oil yield. A total of 1204 biological seeds were collected and sown in a general tree nursery at Ngetta Zonal Agricultural Research and Development Institute (NgeZARDI)during the month of June 2018 in a randomized incomplete block design with three replications. Results: Significant variation (χ = 526; p < 0.01) was observed in seedling phenotypic traits within and between populations. Regression equation for height growth and leaf size index were given asy = 0.3787 + 12.671x and y = 0.6483 + 15.413x respectively. Root collar diameter was more correlated to leaf size index (0.425) than to height growth (0.30). Clustering of shea tree seedlings based on phenotypic growth traits revealed one aggregated cluster indicating that most of the seedlings from the five populations were similar (Jaccard index 0.92, p < 0.01). However, clustering based on SNP markers revealed three different populations. We recorded higher growth (χ = 708; p< 0.001) in Arua shea population (19.69 cm)compared to the population average (19.04 cm). Red seeded; thin pulped and hairy fruited shea tree ethnovarieties assumed faster growth than the rest. Conclusions: The phenotypic analysis of shea tree seedlings revealed some fast-growing genotypes from the five studied populations. Thesegenotypes can be selected for faster growth for shea tree breeding in Uganda.Item Volatile Organic Compound Based Markers for the Aroma Trait of Rice Grain(Journal of Agricultural Science, 2020) Ocan, David; Rongrong, Zhang; Odoch, Martin; Nuwamanya, Ephraim; Ibanda, Angele P.; Odong, Thomas L.; Lamo, Jimmy; Fitzgerald, Anne M.; Daygon, Venea D.; Rubaihayo, Patrick R.A study was conducted to determine the volatile organic compounds (VOCs) associated with rice grain aroma in 37 commonly grown lines within Uganda, as well as elites. The aim of the study was to identify potential volatile biochemical markers, if any, for the rice grain aroma trait. Certified rice seeds were obtained from the Uganda National Crops Resources Research Institute germplasm collection. The seeds were sown into experimental plots, under field conditions and the mature paddy harvested. Polished rice grains were heated to 80 oC and the liberated VOCs subjected to untargeted metabolite analysis using gas chromatography-time-of-flight mass spectrometry. In total, nine functional groups were present; hydrocarbons, alcohols, ketones, aldehydes, N-containing compounds, S-containing compounds, esters, oxygen heterocycles and carboxylic acids. More specifically, 148 VOCs were identified across the 37 rice lines, of which 48 (32.4%) including 2-acetyl-1-pyrroline (2-AP) appeared to elucidate the difference between non-aromatic and aromatic rice. Furthermore, 41 (27.7%) VOCs were found to be significantly correlated with 2-AP abundance, the principle rice aroma compound. Amongst the 41 VOCs, only ten compounds were found to contribute highly towards variation in 2-AP abundance, indicative of their possible modulation roles in regard to rice aroma. Within the ten influential volatiles, three aroma active compounds; toluene, 1-hexanol, 2-ethyl and heptane, 2,2,4,6,6-pentamethyl- were established as the most reliable biochemical surrogates to the rice aroma trait. Thus, the aforementioned compounds may be used in rice breeding programme for enhancing development of the grain aroma trait.