Browsing by Author "Lamo, Jimmy"
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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 Challenges and innovations in achieving zero hunger and environmental sustainability through the lens of sub-Saharan Africa(Outlook on Agriculture, 2020) Okello, Moses; Lamo, Jimmy; Ochwo-Ssemakula, Mildred; Onyilo, FrancisAchieving zero hunger by 2030 often raises the issue of environmental protection or sustainable social development among policy makers due to the environmental footprint of intensifying agricultural production across the continent. Sub- Saharan Africa (SSA) has one of the fastgrowing populations with more than half of the global growth between now and 2050. The challenge now lies in feeding the ever-growing population that is exerting pressure on the limited available resources. Doubling the agricultural productivity of small-scale farmers by 2030 (SDG 2.3) remains a daunting task for researcher and policy makers to address on the continent that now relies much on imports of food. Exploitation of the untapped massive land resources for agricultural production poses threats to sustainability. However, the challenges of global warming cannot be left out of this discussion since it has direct impact on future productivity on the continent. Climate change that has been projected to mostly affect the poorer countries also present trials to the food system through increased diseases and weather extremes of floods and droughts. Questions are yet to be answered on which tradeoffs and synergies if any need to be made to achieve zero hunger in Africa by 2030. This synopsis critically breaks down the conflicts, tradeoffs and synergies of how a continent with such massive agricultural production potential can navigate sustainably to achieve zero hunger, self-sufficiency and exports prospects while conserving the environment and natural resources. Evident deployment of new and improved technologies especially advanced biotechnology tools will be critical in achieving zero hunger by 2030. The adaptation needs of the continent are broad including institutional, social, physical and infrastructural needs, ecosystem services and environmental needs, and financial and capacity uncertain impacts.Item Combining ability for resistance to rice yellow mottle virus disease in interspecific and intraspecific rice Genotypes(African Journal of Crop Science, 2015) Munganyinka, Esperance; Edema, Richard; Lamo, Jimmy; Gibson, Paul; Rukundo, PlacideEstimates of combining ability for resistance to rice yellow mottle virus disease (RYMV) were obtained in the green house of National Crops Resources Research Institute, Uganda. The study involved forty-one F2’s diallel crosses and their five intraspecific and four interspecific parental lines. Effects of both general combining ability (GCA) and specific combining ability (SCA) for RYMV reactions were significant, with a preponderance of GCA effects. Of parental lines used in this study, Naric 1, Nerica 6 and WAC 116 were good combiners for transferring resistance genes to their progenies. In this study, most genotypes with good resistance were good general combiners expect Gigante, that despite its good mean performance, combined badly for resistance to RYMV. The crosses with the best resistance were Naric 1x Gigante, Naric 1x Nerica 6, Nerica 6 x Nerica 4 and Nerica 1 x Nerica 6. From this study, we suggest that selection of parents as donors for resistance should consider both GCA and parental performance. On the basis of predominant additive genetic effects observed in the present study, we believe that combinations of interspecific parents may be used to produce rice varieties resistant to RYMV, and that selection in early selfing generations should be effective.Item Comparison of Response to Nitrogen between Upland NERICAs and ITA (Oryza sativa) Rice Varieties(Journal of Agricultural Science, 2012) Onaga, Geoffrey; Asea, Godfrey; Lamo, Jimmy; Kikafunda, Joseph; Bigirwa, GeorgeAverage yields of upland rice are the lowest in Uganda, and most of the productivity gains attributed to improved varieties are related to increased area of production from clearing virgin lands for rice production. In a bid to optimize productivity, we compared the effect of four nitrogen fertilizer treatments: 0, 40, 80 and 120 kgN/ha and two variety types (ITAs (Oryza sativa) and NERICAs (New rice for Africa)) on grain yield and yield parameters in four locations. Combined analysis of variance revealed that nitrogen fertilizer increased mean grain yields from 2116-5200 kg/ha in the NERICAs and 2331-5100 kg/ha in the ITAs. In all the study areas, NERICA 4 and NARIC 2 outperformed NARIC 1 and NERICA 1, and yield trends were consistent over the years suggesting that the two varieties respond better to N fertilizer application. However, the productivity gains are probably related to genetic potential of the varieties rather than the N fertilizer effect, as reflected by the consistent relative performance between 0 N and other N rates. The heavier grains of NARIC 2 and NERICA 4 suggest greater dry matter accumulation before heading, as these varieties have a longer period of vegetative growth. The significant interaction of location x fertilizer and location x variety reveals the need for evaluating the nitrogen-supplying power of soils in the various cropping systems in the country.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 Diversity analysis and genomewide association studies of grain shape and eating quality traits in rice (Oryza sativa L.) using DArT markers(PLoS ONE, 2019) Mogga, Maurice; Sibiya, Julia; Shimelis, Hussein; Mbogo, Daniel; Muzhingi, Tawanda; Lamo, Jimmy; Yao, NasserMicroarray-based markers such as Diversity Arrays Technology (DArT) have become the genetic markers of choice for construction of high-density maps, quantitative trait loci (QTL) mapping and genetic diversity analysis based on their efficiency and low cost. More recently, the DArT technology was further developed in combination with high-throughput next-generation sequencing (NGS) technologies to generate the DArTseq platform representing a new sequencing tool of complexity-reduced representations. In this study, we used DArTseq markers to investigate genetic diversity and genome-wide association studies (GWAS) of grain quality traits in rice (Oryza sativa L.). The study was performed using 59 rice genotypes with 525 SNPs derived from DArTseq platform. Population structure analysis revealed only two distinct genetic clusters where genotypes were grouped based on environmental adaptation and pedigree information. Analysis of molecular variance indicated a low degree of differentiation among populations suggesting the need for broadening the genetic base of the current germplasm collection. GWAS revealed 22 significant associations between DArTseq-derived SNP markers and rice grain quality traits in the test genotypes. In general, 2 of the 22 significant associations were in chromosomal regions where the QTLs associated with the given traits had previously been reported, the other 20 significant SNP marker loci were indicative of the likelihood discovery of novel alleles associated with rice grain quality traits. DArTseq-derived SNP markers that include SNP12_100006178, SNP13_3052560 and SNP14_3057360 individually co-localised with two functional gene groups that were associated with QTLs for grain width and grain length to width ratio on chromosome 3, indicating trait dependency or pleiotropic-effect loci. This study demonstrated that DArTseq markers were useful genomic resources for genome-wide association studies of rice grain quality traits to accelerate varietal development and release.Item Effect of Soil Moisture Stress Duration on the Growth Characteristics and Yield of Rice Cultivars(Journal of Agriculture and Environmental Sciences, 2016) Momolu, Emmanuel P.; Katuromunda, Sylvester; Lamo, JimmySoil moisture stress is a major constraint to the productivity of rice under rain-fed conditions. A study was conducted to establish the effect of moisture stress duration on the growth characteristics and grain yields of rice cultivars, namely Namche-1, Namche-3 and Agoro. Rice plants were subjected to moisture stress at tillering and a thesis in the screen house. Moisture stress at tillering stage caused significant leaf rolling in Agoro than in Namche-3, but at a thesis Agoro was the least (P≤0.05) affected. Moisture stress at tillering and a thesis significantly reduced the number of tillers in Agoro, but not in Namche cultivars. The growth period of Agoro was significantly longer than that of the control when it was stressed at tillering for 15 days, but stressing Agoro at a thesis didn’t affect its maturity period. Stressing Namche cultivars at tillering and a thesis increased (P≤0.05) their maturity periods, though these periods were shorter (P≤0.05) than that of Agoro. Grain yields for all the cultivars at tillering and a thesis decreased as the stress period was prolonged. Grain yields of Namche cultivars were higher (P≤0.05) than that of Agoro. Therefore, the growing of Namche cultivars in areas with insufficient moisture for rice production would be appropriate.Item Evaluation of rice genotypes for resistance to the stalk-eyed fly (Diopsis longicornis) in rice in Uganda(International Journal of Agronomy and Agricultural Research (IJAAR), 2016) Ganteh Weelar, Charles; Otim, Michael Hilary; Lamo, Jimmy; Awio, Bruno; Ochwo-Ssemakula, MildredGlobally, rice production is limited by abiotic and biotic factors. Of the insect pests attacking rice, the stalk-eyed fly is the most abundant. Major rice growing districts in Uganda are affected, and varieties grown by farmers are susceptible. The objective of this study was to identify sources of resistance to stalk-eyed flies among improved rice genotypes in Uganda. Fifty genotypes from the Africa Rice Centre, IRRI, South Korea and the National Crops Resources Research Institute (NaCRRI) in Uganda were screened under cage and field conditions at NaCRRI. Trials were laid out in an alpha lattice design, with 3 replications, for both experiments. Natural infestation (D. longicornis or D. apicalis) was used in the field while cage trials utilized artificial infestation with D. longicornis. Data on deadhearts were collected from seedling to tillering stages, at 7, 14, 21 and 28 days. Analyses of variance were performed using restricted maximum likelihood. Infestation levels for 31 (62%) rice genotypes were the same under both field and cage conditions, 4 (8%) genotypes showed higher susceptibility in the cage than in the field and 15 (30%) were more resistant in the cage than in the field. Genotypes NERICA 4, TXD306, NM7-22-11- B-P-1-1 and K85 were identified as the most resistant varieties. F3 genotypes (GSR IR1- 5-S14-S2-Y1 x K85, Gigante x NERICA4, NERICA4 x Gigante, NERICA1x NERICA4, NERICA4 x NERICA6, and NERICA4 x SUPA) were also found resistant. These genotypes were recommended for release and further advancement, respectively.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 Identication Of New Sources Of Rice Genotypes (Oryza Sativa L.) Tolerant To Cold Stress(Research Square, 2022) Tolosa Entele, Kidist; Edema, Richard; Lamo, Jimmy; Tilahun, Nigat; Abebe, Desta; Kebede, WorkuRice crop is adversely affected by cold stress which is a common problem in the highland areas of central East Africa (Uganda, Rwanda, north east Tanzania and Kenya) and Madagascar. Cold stress is known to cause 26% to 80% yield loss. Currently, rice production in Uganda is mostly growing to the low altitude areas as there is lack of cold-tolerant varieties that can grow in the higher altitudes of the country. None of the released varieties in Uganda are tolerant cold. The few cold-tolerant lines that have been identified are short-grain types, though Ugandan consumers generally prefer long-grain size. This research aimed at identifying new sources of cold tolerant rice genotypes with preferred traits. A total of 50 lines arranged in a 5x10 alpha lattice design with two replications were used for both stressed and non-stressed experiments. Twenty one (21) days old seedlings were stressed at 10oC in cold air for 10 days and the other remained under normal ambient temperature. IRRI Standard Evaluation System (SES, 2013) was used to score the effect of cold stress on leaf morphology (leaf wilting score) and on leaf color (leaf yellowing score) after 7 day recovery. This study revealed eight highly cold tolerant (SCRID091-20-2-2-4, GIZA 177, NERICA 1, MET P27, MET P23, MET P60, MET P20 and MET P5) in which only GIZA 177 was short grain and fifteen tolerant varieties (MET P32, MET P11, MET P2, MET P17, MET P3, MET P24, MET P16, MET P37, MET P18, MET P9, MET P40, MET P31, MET P39, MET P22, MET P36) were identified.Item Identification of rice genotypes tolerant to submergence at seedling stage in Uganda(Journal of Plant Breeding and Crop Science, 2019) Bildadi Mlaki, Anna; Gibson, Paul; Edema, Richard; Habineza, Jean Claude; Mwanje, Gerald; Lamo, Jimmy; Nuwamanya, EphraimFloods have destroyed over 2000 acres of rice in Uganda which affected yield and caused losses to farmers. This problem is more pronounced when fields are not well leveled, and the mode of irrigation is by surface flooding. Majority of lowland rice fields in East African region are of this nature and are thus prone to yield losses. There are no submergence tolerance varieties identified in Uganda, so far. To address this problem, breeding for submergence tolerance is the most ideal and promising strategy in rice. As a first step, genotypes tolerant to submergence need to be identified which is the objective of this study. 29 rice genotypes were morphological characterized in screen house and field conditions while 34 rice genotypes were molecularly characterized. Results suggested significant differences in the performance of genotypes both in the screen house and under field conditions in which varieties Swarna, IRRI SUPA 3 and KOMBOKA showed approximately 80% and above survival rate with Swarna variety ranking first. Molecular characterization of rice genotypes revealed that, out of 34 genotypes, 30 genotypes scored presence for Sub 1A-2 allele while, four genotypes were neither Sub1A-1 nor Sub 1A- 2 alleles. None of the tested genotypes were carrying Sub 1A-1 allele.Item Improved Upland Rice: Adaptability, Agronomic and Farmer Acceptability Assessment under Semi-Arid Conditions of South Western Uganda(Open Access Library Journal, 2019) Kankwatsa, Peace; Muzira, Robert; Mutenyo, Hellen; Lamo, JimmyEnhancing the ability of plants to tolerate abiotic and biotic stresses is the current strategy for increasing agricultural productivity worldwide. Improved upland rice varieties characterized by early maturity, high disease resistance, high drought tolerance, high yielding potential, high grain quality and marketability are required by farmers to increase upland rice production to meet the increasing food and income demands. Improved and local upland rice varieties were evaluated across two seasons with and without fertilizer application. Insufficient soil water availability, low soil fertility and the blast disease were the major stresses that affected upland rice in the Rubirizi and Mitooma experimental sites in the South Western Agro Ecological Zone of Uganda. Integration of improved rice variety and soil fertility amendment with fertilizer plus proper crop management cultural practices resulted in high agronomic performance. Varieties NamChe 4, NamChe 5 and E22 showed superior performance over the other varieties in the field, and had significantly high probability (P ≤ 0.15) of being accepted by farmers. The early maturing NERICA 10, late maturing NERICA 6, SUPERICA 1 and Local Var., had high probabilities of being rejected because of low yielding, late maturity, drought intolerance, small panicle size, poor grain filling and high susceptibility to rice blast caused by Magnaporthe grisea . Therefore, improved varieties have great potential of increasing rice production in SWAEZ-Uganda, if farmers adopt the multi-technology integration approach.Item Inheritance of resistance to brown spot disease in upland rice in Uganda(Journal of Plant Breeding and Crop Science, 2017) Mwendo, Marco Martin; Ochwo-Ssemakula, Mildred; Mwale, Saul Eric; Lamo, Jimmy; Gibson, Paul; Edema, RichardBrown spot disease caused by Bipolaris oryzae [Breda de Haan (Shoem.)] is one of the most important diseases affecting rice (Oryza sativa L.) worldwide. Host plant resistance is considered an effective, cheap and environment friendly means of managing this disease. Nine rice genotypes with varying resistance levels were crossed in a full diallel mating design including reciprocals and parents. Parents, reciprocals and F2 progenies were evaluated in an alpha lattice design in the screen house and field trials at the National Crops Resources Research Institute in Uganda in 2013-2014. The objectives of the study were to determine the mode of inheritance for resistance to brown spot disease and characterize segregation patterns of specific F2 progenies. Significant (P ≤0.001) variation for brown spot resistance occurred among the tested genotypes. The general combining ability (GCA) and specific combining ability (SCA) effects of brown spot disease scores were both significantly different (P≤0.001), indicating that both additive and non-additive genetic effects were present. There was, however, a predominance of non-additive genetic effects in the genetic control of brown spot resistance as shown by low estimates of baker’s ratio (0.29) and narrow sense coefficient of genetic determination (0.24), implying that progeny performance could not be predicted from parents GCA effects as it was better only in specific crossing combinations. Segregation patterns also indicated that resistance to brown spot was controlled by one or two dominant genes. The reciprocal effects for the crosses were significantly different (P ≤ 0.05), suggesting that cytoplasmic genetic effects modified the expression of resistance. Care should, therefore, be taken when selecting female parents during hybridization. Family-based breeding programs would also be effective for improving resistance to brown spot in rice varieties adapted to Uganda.Item Irrigated and Rain-Fed Lowland Rice Breeding in Uganda: A Review(IntechOpen, 2021) Lamo, Jimmy; Ochan, David; Abebe, Desta; Zewdu Ayalew, Zelalem; Mlaki, Anna; Ndikuryayo, CyprienSince introduction of rice into Uganda in 1904, improvement of the irrigated and rain-fed lowland types was undertaken to address a number of production and quality constraints in three consecutive and overlapping phases. The initial phase was achieved through evaluation of introduction, selection of promising lines and subsequent release of the selected lines for production by the farmers. In the second phase, genetic potential of traits and characteristics of interest were analyzed and used to guide selection of suitable parents for hybridization and the third phase employed genotyping approach in screening and selection of the parental lines and the segregating populations to enhance the breeding efficiency for the traits of importance. Simultaneously, the key production constraints addressed included resistance to rice yellow mottle virus (RYMV), rice blast, bacterial leaf blight and narrow leaf spot diseases as well as submergence tolerance and cold tolerance. The quality traits considered for the improvement alongside the grain yield parameters were the grain aroma, amylose content, shape and size. These interventions have resulted into release and wide adoption of seven rice varieties in Uganda besides several breeding lines which have informally diffused into different major rice production agro-ecology. Subsequently, it can be concluded that a substantially strong and functional breeding platform for rice in Uganda has been established.Item Mode of inheritance of resistance to the stalk-eyed fly (Diopsis longicornis) in rice(International Journal of Agronomy and Agricultural Research, 2017) Ganteh Weelar, Charles; Lamo, Jimmy; Otim, Michael Hilary; Awio, Bruno; Ochwo-Ssemakula, MildredStalk eyed flies (D. longicornis and D. apicalis) are pests of economic importance on rice. Of the two species of stalk- eyed fly, D. longicornis is the most prevalent and destructive. To determine the mode of inheritance for resistance to the stalk-eyed fly in rice in Uganda, crosses were made among eight parental lines (NERICA4, TXD306, K85, NM7-22-11-B-P-1-1, NERICA1, NERICA6, NAMCHE2 and PAKISTAN) selected on the basis of their response to the stalk-eyed fly, high yield and early maturity. Of the eight, four genotypes [NERICA4, TXD306, and NM7-22-11-B-P-1-1 and K85], exhibited lower levels of deadheart occurrence and were crossed using the North Carolina II mating design with four susceptible genotypes [NERICA1 and NERICA6, PAKISTAN, and NAMCHE2]. Studies on combining abilities were conducted on 16 F1 hybrids along with the eight parents. Narrow sense coefficients of genetic determination (NSCGD) were low to moderate (0.09 - 0.33) and broad sense coefficients of genetic determination (BSCGD) were moderate to high (0.38 - 0.89) for traits studied. Both GCA and SCA effects were significant for percentage of deadhearts. However, Baker’s ratio was less than 0.5 (0.37) for deadhearts, indicating that both additive and non-additive gene effects were involved in resistance to the stalkeyed fly, although non-additive gene effects were more important. NERICA4 andK85 were found to be good general combiners for increasing resistance. The crosses Pakistan × TXD306 and NERICA1× NM7-22-11-B-P-1-1 were identified as promising lines for advancement.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 A New Cheap and Efficient Single-Grain Shatter Tester for Use in Rice Breeding(Crop science, 2011) Lamo, Jimmy; Tongoona, Pangirayi; Okori, Patrick; Derera, John; Hendricks, Roelof; Laing, MarkGrain shattering, also called grain shedding, is the relative ease with which rice (Oryza sativa L.) seed is dislodged from the pedicel at maturity. Several qualitative methods have been used to assess grain shattering and they tend to underestimate yield loss. Equipments available for quantitative assessment of grain shattering are mostly laboratory based. However, a recently developed prototype in Japan for fi eldwork can be used, but the cost is prohibitive. An improved grain-shattering tester that uses a hand-held device has been developed and reported here. It is an improvement over the stationary laboratory device. It has the following modifi cations: a crocodile clip instead of a bench clamp and a helical spring for testing tensile material instead of tension gauge. The new device is affordable, handy for fi eldwork, and effective for large experimental trials. This equipment was designed and developed at the University of KwaZulu-Natal (UKZN) mechanical workshop (Pietmeritzburg, South Africa). Its effi ciency was tested at the National Crops Resources Research Institute (NaCRRI) at Namulonge, Uganda. The effi ciency was tested by fi rst estimating yield loss in selected test plants using a method that involves shaking panicles. This fi nding was compared with the minimum force required to dislodge the grains using this new device and a high correspondence of R2 = 99.9% was found. This new equipment has therefore been recommended for fi eld assessment of grain shattering.Item Population diversity of rice bacterial leaf blight isolates in Uganda(Asian Journal of Plant Science and Research, 2013) Habarurema, Innocent; Edema, Richard; Gibson, Paul; Lamo, Jimmy; Asea, Godfrey; Séré, Yacouba; Gasore, Elie R.The deployment of resistant cultivars is the best option to control bacterial leaf blight (BLB) and requires an understanding of the pathogen diversity. BLB caused by Xanthomonas oryzae pv.oryzae is a destructive disease of rice (Oryza sativa L.) in Uganda. Unfortunately, detailed information on Ugandan pathogen populations is not available. A set of 21 differential rice genotypes that have known resistance genes were used in a split plot design to test for differential virulence of six different isolates of X.oryzae pv.oryzae obtained from seed samples collected from Eastern Uganda. Statistical analysis showed diversity among isolates. The susceptibility of the differentials with two to four-gene combinations and the resistance of IR24 to Ugandan isolates were unusual and, therefore suggested a different pattern between Asian and Ugandan isolates at pathological level. Although the isolates were fewer in number, attempts to classify them into pathogenic races gave rise to 6 different races, as each isolate caused a particular virulence pattern on the differentials. The six races formed two significantly different (p ≤ 0.05) groups of one race (UX041) and five races (UX051, UX00, UX050, UX058 and UX044). These races would be used in screening rice germplasm available and/or newly introduced to Uganda.Item Quantifying rice yield gaps and their causes in Eastern and Southern Africa(Journal of Agronomy and Crop Science, 2020) Senthilkumar, Kalimuthu; Rodenburg, Jonne; Dieng, Ibnou; Vandamme, Elke; Silas Sillo, Fitta; Johnson, Jean-Martial; Rajaona, Arisoa; Amielle Ramarolahy, Jemima; Gasore, Rene; Abera, Bayuh Belay; Kajiru, Geophrey J.; Mghase, Jerome; Lamo, Jimmy; Rabeson, Raymond; Saito, KazukiThe demand for rice in Eastern and Southern Africa is rapidly increasing because of changes in consumer preferences and urbanization. However, local rice production lags behind consumption, mainly due to low yield levels. In order to set priorities for research and development aimed at improving rice productivity, there is a need to characterize the rice production environments, to quantify rice yield gaps—that is, the difference between average on-farm yield and the best farmers’ yield—and to identify causes of yield gaps. Such information will help identifying and targeting technologies to alleviate the main constraints, and consequently to reduce existing yield gaps. Yield gap surveys were conducted on 357 rice farms at eight sites (19–50 farmers per site) across five rice-producing countries in Eastern and Southern Africa—that is Ethiopia, Madagascar, Rwanda, Tanzania and Uganda—for one or two years (2012–13) to collect both quantitative and qualitative data at field and farm level. Average farm yields measured at the eight sites ranged from 1.8 to 4.3 t/ha and the average yield gap ranged from 0.8 to 3.4 t/ha. Across rice-growing environments, major causes for yield variability were straw management, weeding frequency, growth duration of the variety, weed cover, fertilizer (mineral and organic) application frequency, levelling and iron toxicity. Land levelling increased the yield by 0.74 t/ha, bird control increased the yield by 1.44 t/ha, and sub-optimal management of weeds reduced the yield by 3.6 to 4.4 t/ha. There is great potential to reduce the current rice yield gap in ESA, by focusing on improvements of those crop management practices that address the main site-specific causes for sub-optimal yields.Item The reaction of intraspecific and interspecific rice cultivars for resistance to rice yellow mottle virus disease(European Journal of Experimental Biology, 2016) Munganyinka, Esperance; Edema, Richard; Lamo, Jimmy; Gibson, PaulA study was conducted in a green house of National Crop Resource Research Institute, Uganda to determine the reaction for resistance to rice yellow mottle virus (RYMV) in nine rice genotypes. Four were interspecific (N-1, N-4, N-6 and Naric 1) and five intraspecific (two locals K5 and K85, and three introduced WAC 116, WAC117 and Gigante). The screening of these parental materials for resistance to RYMV was done by artificial inoculation with a virulent isolate from Iganga. For among the materials tested, none was found to be immune. The results revealed four patterns of reaction to RYMV among the cultivars: three resistant (WAC 116, WAC 117 and Naric1), four moderately resistant (Nerica 6, Nerica 4, Nerica 1 and Gigante) and two susceptible (K85 and K5). In the current study, Gigante was recorded to have the severity of RYMV symptoms. Furthermore, lines WAC 116, WAC 117 and Naric1 were identified as sources of resistance to RYMV, and therefore candidates for use as parents to improve resistance in susceptible preferred local rice varieties.