Browsing by Author "Alibu, Simon"
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Item Agronomic Evaluation of Alternative Lowland Rice Varieties for Farmers in Uganda; A Case of Aromatic Rice(Journal of Food Security, 2022) Alibu, Simon; Obura, Morish; Ekebu, James; Nampamya, Doreen; Lamo, Jimmy; Asea, Godfrey; Tae-Seon, ParkRice has recently become an important crop for tackling food insecurity and poverty in Uganda. Over three-quarters of the country's local rice production occurs in irrigated and rain-fed lowlands in eastern and northern Uganda. However, breeding programs and seed systems have only partially met farmers' expectations for new lowland rice varieties and seeds recently, so farmers are sticking with old varieties. However, a new high-yielding, early-maturing, and most importantly, aromatic variety, NARORICE-1, released in 2019, seems to offer a new ray of hope for lowland rice farmers. This study compared the agronomic performance of NARORICE-1 and two promising KAFACI lines to a popular farmer's variety, WITA-9, in central, eastern, and northern Uganda. These varieties were evaluated for growth and yield response to higher seedling counts per hill when transplanted. Doho was the most productive location with an average rice yield of 6.1 t ha–1, significantly higher than NaCRRI and Olweny with 3.9 and 3.7 t ha–1, respectively. The yield performance of NARORICE-1 was comparable to that of the popular farmer's variety WITA-9. Increasing the number of seedlings per hill from three to seven during transplanting had no clear effect on the paddy yield of NARORICE-1. Besides higher yield potential, NARORICE-1's other additional beneficial traits such as aroma, shorter growing time, and higher milling efficiency have made it one of the growers' favorites.Item Detection of sister-species in invasive populations of the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) from Uganda(PloS one, 2018) Otim, Michael H.; Tay, Wee T.; Walsh, Thomas K.; Kanyesigye, Dalton; Adumo, Stella; Abongosi, Joseph; Ochen, Stephen; Sserumaga, Julius; Alibu, Simon; Abalo, GraceThe fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith) is a species native to the Americas. This polyphagous lepidopteran pest was first reported in Nigeria and the Democratic Republic of São Tome and Principe in 2016, but its presence in eastern Africa has not been confirmed via molecular characterisation. In this study, FAW specimens from western and central Uganda were identified based on the partial mtDNA COI gene sequences, with mtDNA COI haplotypes matching those identified in Nigeria and São Tome . In this study, we sequence an additional partial mtDNA Cyt b gene and also the partial mtDNA COIII gene in Ugandan FAW samples. We detected identical mitochondrial DNA haplotypes for both the mtDNA Cyt b and COI partial genes, while combining the mtDNA COI/Cyt b haplotypes and mtDNA COIII haplotypes enabled a new maternal lineage in the Ugandan corn-preferred FAW samples to be identified. Our results suggested that the African incursions of S. frugiperda involved at least three maternal lineages. Recent full genome, phylogenetic and microsatellite analyses provided evidence to support S. frugiperda as likely consisted of two sympatric sister species known as the corn-preferred and rice-preferred strains. In our Ugandan FAW populations, we identified the presence of mtDNA haplotypes representative of both sister species.Item Developing Lowland Rice Germplasm with Resistance to Multiple Biotic Stresses through Anther Culture in Uganda(The Korean Society of International Agriculture, 2015) Lamo, Jimmy; Gyoung-rae, Cho; Ininda, Jane; Kofi Ayirebi, Dartey Paul; Ekebu, James; Ekobu, Moses; Alibu, Simon; Okanya, Stephen; Oloka, Bonny; Otim, Michael; Asea, Godfrey; Kyung-Ho, KangThe lowland rice genotypes grown in Uganda were introduced in the 1970s. These genotypes (now landraces) are threatened by multiple biotic stresses namely; Rice Yellow Mottle Virus (RYMV) disease, Bacterial Leaf Streak(BLS). Bacterial Leaf Blight (BLB), and Rice Blast (BL). There are currently no rice lines with multiple resistance to these stresses although attempts have been made to develop them through hybridization involving cultivated, local and introduced lines and four varieties with tolerance to RYMV have been released. The use of potential resistance donor such as the traditional African cultivated rice, Oryza glaberrima, could be an alternative approach to furnish multiple resistance to the cultivated rice. The rice germplasm developed from a cross of an Oryza glaberrima from Niger Delta and Milyang23, a high-yielding Korean rice variety were evaluated for multiple resistance in Uganda as a Korea-Africa Food & Agriculture Cooperation Initiative (KAFACI)-Alliance for a Green Revolution in Africa (AGRA) joint cooperative project, “Enhancement of High Yielding Rice Germplasm in African Countries through Anther Culture Breeding”. Milyang23 was back crossed 4 times with Oryza. glaberrima and fixed through anther culture in Korea. An evaluation of 50 lines generated showed that up to 98%, 92%, 88% and 88% of the test plants showed resistance to the RYMV, BLS, BLB and BL diseases, respectively. There was no symptoms of the four diseases in 74% of the genotypes tested. The plants that showed symptoms of the three diseases had scores of not more than 3 on a 1 to 9 scale. This preliminary finding demonstrates that these generations of rice lines could help solving the current problem of susceptibility to multiple diseases.Item Farmer’s Knowledge and Perceptions on Rice Insect Pests and Their Management in Uganda(Agriculture, 2016) Alibu, Simon; Otim, Michael H.; Okello, Stella E. A.; Lamo, Jimmy; Ekobu, Moses; Asea, GodfreyRice is a new crop in Uganda, but has quickly grown in importance. Between 2000 and 2010, total area under rice cultivation in the country grew by 94% from 140,000 ha. Changes in the agro ecosystem due to expansion in rice area may have altered the pest status of rice insect pests. However, far too little attention has been paid to assessing the prevalence and importance of rice insect-pests in Uganda. In this study, we interviewed 240 lowland-rice farming households from eight districts within the north, east and central regions of Uganda about their perceived insect-pest problems and control measures employed, if any. A semi-structured questionnaire was used. The farmers ranked rice insect pests as the most important biotic constraint in rice production, with stem borers and the African rice gall midge (AfRGM) perceived to be the 1st and 2nd most detrimental insect pests, respectively. In spite of this, only 36% of the respondents could positively identify symptoms of AfRGM damage on rice plants, while 64% were familiar with stem borer damage. Over 60% of interviewed farmers expressed confidence in the effectiveness of insecticides for controlling rice insect pests. Cultural control measures were not popular among the farmers.Item Genotypic variation in coleoptile or mesocotyl lengths of upland rice (Oryza sativa L.) and seedling emergence in deep sowing(African Journal of Agricultural Research, 2012) Alibu, Simon; Saito, Yuri; Shiwachi, Hironobu; Irie, KenjiRain-fed upland rice (Oryza sativa L.) is one of the important crops in Sub-Saharan Africa (SSA) accounting for over 40% of the area under rice cultivation. In SSA, upland rice is primarily established by dry direct seeding (DS), which saves time and labour, although DS is associated with poor seedling emergence and establishment. It is thought that coleoptile and mesocotyl elongation in rice seedlings enhance emergence in deep sowing. A screen house study was conducted from May to December 2011 at Tokyo University of Agriculture in Japan to determine the effect of coleoptile and or mesocotyl elongation on seedling emergence in deep sowing. Six upland rice genotypes which vary in coleoptile + mesocotyl lengths, and another ten genotypes varying only in mesocotyl lengths were selected and evaluated for seedling emergence at 2, 4, 6 and 8 cm sowing depths. The experiment was laid out in a split-plot design based on randomised complete blocks. Seedling emergence was significantly reduced by sowing depth. Across the genotypes, seedling emergence was not associated with coleoptile + mesocotyl length. And although coleoptile and mesocotyl lengths both increased with sowing depth, seedling emergence in deep sowing was affected largely by mesocotyl elongation rather than coleoptile elongation. We found that only those genotypes that significantly elongated their mesocotyls like Nutsurikui and Plu-go were able to emerge from deep sowing. Our results therefore suggest that seedling emergence in dry direct seeded upland rice can be improved by planting genotypes with long mesocotyls.Item How Does Water Stress and Nitrogen Fertilizer Affect the Growth and Yield of Upland Rice (Oryza Sativa L.)(Journal of Food and Nutrition Research, 2021) Alibu, Simon; Mamadou, FofanaWater stress and inadequate nitrogen (N) fertilizer are important factors that simultaneously limit the growth and yield of upland rice. In this study, we examined the interactive effects of N fertilizer application and water stress timing on the growth and productivity of upland rice. The experiment was set up as a randomized complete block design (RCBD) with 2 replications. Toyohatamochi rice was fertilized with three levels of N (30, 60, and 90 kg/ha) and subjected to water stress at different growth stages (early vegetative, active tillering, maximum tillering stages, and then at 10 and 20 days after heading). We did not find any statistically significant interactive effects of water stress timing and N on growth, yield, and dry matter productivity, although N appeared to increases the sensitivity of upland rice to water stress. Water stress at maximum tillering and 10 days after heading (DAH) both reduced grain yield by 50% and dry matter productivity by 49% and 38% respectively. In contrast, early vegetative stress reduced grain yield by a modest 20% despite decreasing dry matter productivity by 40%. Nevertheless, the grain yield of rice stressed at the early vegetative stage increased with N, suggesting a possibility of salvaging grain yield in rice that has suffered water stress at the early vegetative stage by enhancing N fertilization. However, after maximum tillering but before 20 DAH water stress caused irrecoverable grain yield loss, even with more N.Item Modest Ag-Extension and Access to Seeds of Aromatic Rice Can Boost Returns of Smallholder Farmers in Uganda, A Case Study(Agriculture, 2022) Alibu, Simon; Obura, Morish; Ekebu, James; Nampamya, Doreen; Lamo, Jimmy; Asea, Godfrey; Tae-Seon, ParkLimited farmer access to quality seeds of improved varieties and knowledge gaps in good agronomic practices are the major factors limiting rice productivity among smallholder farmers in Uganda. Promoting high yielding aromatic rice varieties alongside good agronomic practices can unlock commercial opportunities for smallholder farmers in rice cultivation, given that 80% of rice consumers in Uganda prefer aromatic rice, which is in short supply. This case study highlights a project’s achievements to accelerate the adoption of improved aromatic rice varieties among smallholder farmers in Uganda. This project supported a few selected farmers with the seed of a new aromatic rice variety, NARORICE-1, and equipped them with agronomic skills to raise their yields from an average of 3.1 to 4.1 t/ha. Line transplanting was identified as a crucial technology to increase rice yields among smallholders. Costly and inaccessible crop-enhancing inputs such as seeds and fertilizers, and an unfair distribution of irrigation water were the two main obstacles farmers face in rice production. Farmers valued NARORICE-1 for its aroma, high yield, and early maturity. The project’s training of a community seed producer improved farmers’ access to NARORICE- 1 seeds, increasing its adoption by 20% in two years. NARORICE-1 is much more in demand than any other variety and attracts a better price, making it an ideal innovation for increasing productivity and farmer’s incomes. An effective seed system and continuous farmer training are vital for accelerating impact.Item Multiple Facets of Nitrogen: From Atmospheric Gas to Indispensable Agricultural Input(Life, 2022) Kabange, N. R.; Lee, So-Myeong; Shin, Dongjin; Lee, Ji-Yoon; Kwon, Youngho; Kang, Ju-Won; Cha, Jin-Kyung; Park, Hyeonjin; Alibu, Simon; Lee, Jong-HeeNitrogen (N) is a gas and the fifth most abundant element naturally found in the atmosphere. N’s role in agriculture and plant metabolism has been widely investigated for decades, and extensive information regarding this subject is available. However, the advent of sequencing technology and the advances in plant biotechnology, coupled with the growing interest in functional genomics-related studies and the various environmental challenges, have paved novel paths to rediscovering the fundamentals of N and its dynamics in physiological and biological processes, as well as biochemical reactions under both normal and stress conditions. This work provides a comprehensive review on multiple facets of N and N-containing compounds in plants disseminated in the literature to better appreciate N in its multiple dimensions. Here, some of the ancient but fundamental aspects of N are revived and the advances in our understanding of N in the metabolism of plants is portrayed. It is established that N is indispensable for achieving high plant productivity and fitness. However, the use of N-rich fertilizers in relatively higher amounts negatively affects the environment. Therefore, a paradigm shift is important to shape to the future use of N-rich fertilizers in crop production and their contribution to the current global greenhouse gases (GHGs) budget would help tackle current global environmental challenges toward a sustainable agriculture.Item Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda(Crop Protection, 2022) Otim, Michael H.; Alibu, Simon; Asea, Godfrey; Abalo, Grace; Sserumaga, Julius Pyton; Adumo, Stella; Alupo, Jane O. Oikeh; Ochen, Stephen; Tefera, Tadele; Bruce, Anani Y.; Beyene, Yoseph; Meisel, Barbara; Tende, Regina; Nang’ayo, Francis; Baguma, Yona; Mugo, Stephen; Oikeh, Sylvester O.Stem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda.Item Potential of Cultivating Dry Season Maize along a Hydrological Gradient of an Inland Valley in Uganda(Agronomy, 2019) Alibu, Simon; Neuhoff, Daniel; Senthilkumar, Kalimuthu; Becker, Mathias; Köpke, UlrichInland valley wetlands with higher soil moisture than surrounding uplands o er a yet unexplored opportunity for increasing maize production in East Africa. For three consecutive years, we conducted field experiments to assess the potential of an inland valley in Central Uganda for producing dry season maize. A randomized complete block design was used with six treatments including farmer’s practice, unfertilized control, organic and inorganic fertilizer applications at high and low rates. These were repeated four times at each of the three hydrological positions of the inland valley (fringe, middle, and center). The maize grain yield of 3.4 t ha1 (mean across treatments and years) exceeded the national yield average by 42%. High and sustained soil moisture in the center position of the inland valley was associated with the highest grain yields irrespective of the year. Due to soil moisture deficit in the fringe and middle hydrological positions, grain yields were not only lower but also highly variable. Intensive manuring with a combination of green and poultry manure produced high yields that were comparable to those with mineral fertilizers (both at 120 kg N ha1). Lower amounts of either mineral or organic fertilizer (60 kg N ha1) provided no yield gain over the unfertilized control. Inland valley wetlands, thus, o er promise for farmers to harvest an additional maize crop during the dry season, thus contributing to farm income and regional food security.