NRU :: Browsing by Author "Edema, R."

Browsing by Author "Edema, R."

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Characterization and Distribution of a Potyvirus Associated with Passion Fruit Woodiness Disease in Uganda
(Plant Disease, 2012) Ochwo-Ssemakula, M.; Sengooba, T.; Hakiza, J. J.; Adipala, E.; Edema, R.; Redinbaugh, M. G.; Aritua, V.; Winter, S.
This article describes the incidence and etiology of a viral disease of passion fruit in Uganda. Symptoms, including those characteristic of passion fruit woodiness disease (PWD), were observed on 32% of plants in producing areas. Electron microscopic observations of infected tissues revealed flexuous filaments of ca. 780 nm. Enzymelinked immunosorbent assays indicated a serological relationship with Cowpea aphid-borne mosaic virus (CABMV) and Passion fruit ringspot virus (PFRSV). In host range studies, only species in the families Solanaceae and Chenopodiaceae were susceptible, and neither Vigna unguiculata nor Phaseolus vulgaris became infected. Coat protein (CP) gene sequences of eight isolates exhibited features typical of potyviruses and were highly similar (88 to 100% identity). However, the sequences had limited sequence identity with CP genes of two of the three potyviruses reported to cause PWD: East Asian Passiflora virus and Passion fruit woodiness virus (PWV). Deduced amino acid sequences for the CP of isolates from Uganda had highest identity with Bean common mosaic necrosis virus (BCMNV) (72 to 79%, with evolutionary divergence values between 0.17 and 0.19) and CABMV (73 to 76%, with divergence values between 0.21 and 0.25). Based on these results and in accordance with International Committee for Taxonomy of Viruses criteria for species demarcation in the family Potyviridae, we conclude that a previously unreported virus causes viral diseases on passion fruit in Uganda. The name “Ugandan Passiflora virus” is proposed for this virus.
Characterization and Evaluation of Potato Genotypes (Solanum tuberosum L) for Tolerance to Drought in Uganda
(American Journal of Potato Research, 2016) Kesiime, V. E.; Tusiime, G.; Kashaija, I. N.; Edema, R.; Gibson, P.; Namugga, P.; Kakuhenzire, R.
Potato production in Uganda is being affected by rainfall fluctuations in both timing and amount, resulting into inadequate soil moisture availability and low productivity. Also, potato production is expanding into locations at lower altitudes, where drought is more common. Therefore, drought stress mitigation measures and coping mechanisms need to be devised to face future challenges of climate change, particularly in developing countries to ensure steady supply of adequate quantities of quality food. This study thus, aimed at characterizing new potato clones from CIP (International Potato Center) for tolerance to drought under Ugandan conditions. Consequently a screen house experiment was conducted twice at Kachwekano Zonal Agricultural Research and Development Institute (KAZARDI) from October 2011 to February 2012 and April to July 2012 to evaluate and characterize eight potato genotypes; five of which were obtained from CIP’s breeding collection for drought tolerance and low altitude areas, and three locally released varieties from Uganda. These clones were tested for drought tolerance at three levels of simulated moisture deficit; 25 % field capacity, 50 % and 100 % field capacity (FC). Data were collected on leaf chlorophyll content, relative leaf water content, number of days to 50 % flowering, percent ground cover, leaf area, plant height, number of stems per plant, stem diameter, stress score, increment in plant height after imposing stress, tuber dry matter content and yield components. Of all the traits evaluated, yield and number of days to 50 % flowering contributed most to drought tolerance among the potato genotypes evaluated. There were significant (P ≤ 0.05) differences among genotypes for all evaluated traits. Results from both growth, physiological and yield parameters revealed that the new potato clones were less affected by drought stress compared to adapted varieties. Total tuber yield was 23 tons per hectare, 11.4 and 8.1 in plots at full field capacity, 50 % and 25 % moisture stressed plots respectively in the first experiment. A similar trend was obtained in the second experiment with 19 tons per hectare, 13.7 and 11.3 respectively. The new clones at highest moisture stress had significantly (P ≤ 0.05) higher yields than adapted varieties providing a promise for possible new varieties and breeding stock in extreme conditions of moisture deficit.
Development of intermittent drought stress tolerant common bean genotypes in Uganda
(African Crop Science Journal, 2014) Amongi, W.; Nkalubo, S. T.; Ochwo-Ssemakula M.; Gibson, P. T.; Edema, R.
Common bean (Phaseolus vulgaris L.) varieties that are high yielding and drought-tolerant are crucial in coping with the effects of drought, that is prevalent among small scale producers living in Uganda. The objective of this study was to assess the level of drought tolerance in bean genotypes to be used for the initial development of drought-tolerant genotypes in Uganda. Three local genotypes and five exotic drought-tolerant lines were phenotyped under well-watered and drought-stress conditions. Drought tolerant genotypes were selected basing on high value for the geometric mean for seed yield and low drought susceptibility indices. The exotic lines, SEN 98, SCR48 and SEN 99, emerged superior in these attributes, and in pod partitioning index (PPI) and pod harvest index (PHI). Thus, these genotypes could be useful sources of genes for drought tolerance in the bean breeding programme in Uganda. The local genotype, NABE 15 was similar to the three promising materials for PPI and PHI. Pods per plant and seed weight were the yield components most affected by drought, with reductions of 82 and 78 %, respectively, for SEN 98.
Distribution and Variability of Pseudocercospora griseola in Uganda
(Journal of Agricultural Science, 2012) Ddamulira, G.; Mukankusi, C.; Ochwo-Ssemakula, M.; Edema, R.; Sseruwagi, P.; Gepts, P.
is highly variable with many different races occurring in different agro-ecological zones. Therefore, for an effective breeding program, there is a need to continuously monitor the distribution and variability of the pathogen as a means of guiding breeders on which races to target. A study was conducted to assess the incidence, severity and variability of P. griseola in bean growing districts of Dokolo, Lira, Apac, Sironko, Mbale, Rakai, Lwengo, Bukomansibi, Kabale and Kisoro in Uganda. Forty five out of 80 isolates collected were tested on a set of 12 international bean differentials cultivars for ALS. Molecular markers were also used to elucidate the variability among isolates. In all districts, ALS was found wide spread with a mean incidence of 49.9%. Dokolo district had the highest disease incidence and severity, while Kisoro registered the lowest values respectively. In terms of altitude, incidence (60%) and severity (45%) were high for bean fields located between 1000-1200 m and low disease incidence (33.6%) and severity (20.7%) for fields lying above 1500 m. The standard differential cultivars and molecular markers defined 12 pathotypes and 30 haplotypes respectively. These belonged to Middle America and Andean group with considerably high level of diversity. Our findings indicated the presence of ALS in Uganda with high incidence, severity and variability across districts and altitudes. Hence strategic interventions involving integrated disease management and breeding for durable resistance are required to manage the disease.
Evaluation of Genomic Prediction Algorithms for Reducing Selection and Breeding Cycles in Shea Tree (Vitellaria Paradoxa)
(Uganda Journal of Agricultural Sciences, 2021) Odoi, J. B.; Prasad, H.; Arfang, B.; Kitiyo, R.; Ozimati, A.; Gibson, P.; Edema, R.; Gwali, S.; Odong, T. L.
The focus of this study was to determine the genomic prediction (GP) algorithms with the highest prediction accuracies for reducing the breeding and selection cycles in Vitellaria paradoxa. The efficiency of the GP algorithms were compared to evaluate five Shea tree growth traits in 708 genotypes with 30734 Single Nucleotide Polymorphic (SNPs) markers, which were reduced to 27063 after removing duplicates. Five hundred forty-nine (77.54%) Shea tree training population and 159 (22.46%) training population were genotyped for 30734 single nucleotide polymorphisms (SNPs) and phenotyped for five Shea tree growth traits. We built a model using phenotype and marker data from a training population by optimizing its genomic prediction accuracy for effectiveness of GS. The phenotype and marker data were used for cross validation of the prediction accuracies of the different models. Prediction accuracies varied among the genomic prediction algorithms based on the five phenotypic traits. We determined the best genomic algorithm that is more suitable for reduction of selection and breeding cycles in Vitellaria paradoxa. The GP algorithms were evaluated and we conclude that rrBLUP is the best for improving the prediction accuracy for reducing the breeding cycle in Shea tree.
Genetic diversity and heritability of tomato parental lines assembled for Ralstonia solanacearum resistance
(African Crop Science Journal, 2024-03-28) Mukamanasasira, G.; Adjei, E.A.; Rubaihayo, P.; Ddamulira , G.; Edema, R.
Bacterial wilt is a disease caused by Ralstonia solanacearum, which affects over 450 plant species and causes significant reduction in crop yields including of tomato (Solanum lycopersicum) worldwide. Developing and identifying tomato genotypes with Ralstonia solanacearum tolerance and high yield potential, presents an opportunity for improvement of crop productivity. The objective of this study was to explore the heritability of tomato resistance against bacterial wilt and the genetic variation within the population for breeding purposes. A breeding population was created by crossing two bacterial wilt-resistant (MT56 and BL333) and three commercially desirable susceptible (Assila, Rambo and Heinz) tomato varieties, using North Carolina Design II, in a screen house at the Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). Results showed that the Area Under Disease Progress Curve was significant (P<0.001), indicating that cumulative disease progress was less in resistant genotypes of segregating generations. Disease severity increased with days after inoculation (DAI), with Heinz showing the highest level of susceptibility. The General Combining Ability for male parent (GCAm) was significant (P< 0.01), and Specific Combining Ability (SCAf×m) and GCAf were significant (P<0.01) for the F2 generation. Broad-sense heritability was higher than the narrow-sense heritability in both F1 and F2 generations, suggesting that non-additive gene action predominately controlled tomato resistance to bacterial wilt infestation. The genetic diversity ranged from 0.5 to 0.6759, with a mean value of 0.5787. Polymorphism Information Content (PIC) varied from 0.375 to 0.6357, with a mean of 0.4888, indicating a high degree of variation. SLM 12-2 was the most polymorphic marker, with a PIC of 0.6357. The Unweighted Pair-Group Method with Arithmetic Average (UPGMA) classified all tomato genotypes into six clusters, namely Clusters 1 and 2 (Susceptible parents), Cluster 3 (Resistant parents), Clusters 4 and 5 (New source of resistance), and Cluster 6 (F1P1×P5).
Identification of Common Bean Genotypes with Dual Leaf And Pod Resistance to Common Bacterial Blight Disease in Uganda
(Crop Science Journal, 2018) Alladassi, B.M.E.; Nkalubo, S.T.; Mukankusi, C.; Kayaga, H.N.; Gibson, P.; Edema, R.; Urrea, C.A.; Kelly, J.D.; Rubaihayo, P.R.
Common Bacterial Blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscans (Xapf), is a serious disease that affects common bean production worldwide. In Uganda, it is the most severe and widely occurring bacterial disease, causing significant yield losses in common bean. Although various sources of resistance have been developed around the world, none of the varieties grown in Uganda is known to be resistant. The objective of this study was to identify lines with combined leaf and pod resistance for introgression into locally adapted but susceptible Ugandan genotypes. A total of 132 common bean accessions was evaluated in a screenhouse and under field conditions, in an 11x12 alpha lattice design. Genotypes were inoculated with a local isolate in a screenhouse; while the plants were left to undergo natural infestation in field. Results indicated significant differences (P<0.001) in genotypic reactions against the CBB disease, with a range of disease scores of 2.2 - 7.8 on leaves and 2.6 - 7.1 on pods (1-9 CIAT disease scale), suggesting high genetic variability among the tested germplasm. Relatively low correlation (r = 0.39) was observed between leaf and pod reactions, suggesting differential expression of CBB resistance in these two plant organs. Overall, four genotypes, NE2-14-8, NE17-14-29, NE14-09-78 and VAX3, consistently showed resistance in both screenhouse and field evaluations, leaf and pod inoculations and at all sampling stages. These genotypes were, therefore, identified for transferring CBB resistance into Ugandan susceptible market class bean varieties.
Identification of new sources of resistance to angular leaf spot among Uganda common bean landraces
(Canadian Journal of Plant Breeding, 2014) Ddamulira, G.; Mukankusi, C.; Ochwo-Ssemakula, M.; Edema, R.; Sseruwagi, P.; Gepts, P.
Breeding for resistance to Angular Leaf spot (ALS), a fungal disease caused by Pseudocercospora griseola (Sacc), is faced with a challenge of the existence of a few resistance sources that are exotic and not well adapted to environmental conditions in Uganda. In addition, P. griseola is a highly variable pathogen that co-evolves with its host, therefore necessitating the continuous identification of new and stronger sources of resistance. Identification of local bean landraces/adapted bean varieties with resistance to ALS would probably quicken the progress of development of resistant cultivars, and reduce yield losses. Seventy four landraces, four commercial varieties, and two controls were screened with four P. griseola pathotypes 1:6, 17:39, 21:39, and 61:63 to determine their ALS resistance levels. One landrace, U00297, showed consistent and strong resistance to the four pathotypes. The inheritance of resistance in U00297 was established from three individual populations derived from crosses with three susceptible cultivars, K132, K131, and Kanyebwa, commercially grown in Uganda. The allelic relationships between U00297 and two existing ALS resistance sources, AND277 and G5686 were tested. Segregation ratios of F2 populations revealed that U00297 resistance to pathotype 17:39 is conferred by a single dominant gene, while digenic epistatic gene interactions were suggested for resistance to other pathotypes. The general and specific combining abilities were significant for resistance revealing the importance of additive and dominant components in the inheritance of ALS resistance. As a resistant parent, U00297 was a good combiner for resistance to pathotype 17:39, and effective resistance source to pathotypes 17:39 and 61:63. The allelic test indicated that the dominant gene in U00297 is independent of resistance genes harboured by resistance sources AND277 and G5686. The information generated is useful to breeding programs targeting developing bean cultivars carrying novel ALS resistance based on genes derived from U00297.
Improvement of Resistance to Fusarium Root Rot through Gene Pyramiding in Common Bean
(African Crop Science Journal, 2012) Obala, J.; Mukankusi, C.; Rubaihayo, P.R.; Gibson, P.; Edema, R.
Fusarium root rot (FRR), caused by Fusarium solani f.sp. phaseoli, is one of the most serious root rot diseases of common bean (Phaseolus vulgaris L.) throughout the world. Yield losses of up to 84% have been attributed to the disease. Development and deployment of resistant materials is the most feasible approach to managing the disease. The objective of this study was to estimate the number of pyramided Fusarium root rot resistance genes among the four resistant lines and determine their effectiveness in improving levels of resistance to Fusarium root rot in the susceptible bean cultivars. Crosses among four Fusarium root rot (Fusarium solani f.sp. phaseoli) resistant common bean (Phaseolus vulgaris) were developed. They involved six inbred lines, MLB-48-89A (M48), MLB-49-89A (M49), G2333 (G2) and G685 (G6), and two susceptible cultivars, K20 and Kanyebwa, The resistant lines were used to develop a double cross (DC) population. The DC F1 and each resistant parent were crossed to each of the two susceptible cultivars to form five-parent and single crosses, respectively. Developed populations were subjected to Fusarium solani f. sp. phasoeli isolate-3 under screenhouse conditions. There were segregation ratios of 15:1 (χ2 = 1.89, P = 0.17), 61:3 (χ2 = 0.18, P = 0.67) and 249:7 (χ2 = 1.74, P = 0.19) indicating that two, three and four genes independently condition resistance to F. solani in lines G2 x G6, M49 x M48 and (M49 x M48) x (G2 x G6). A good fit of only four genes in the double cross compared to two in the G2 x G6 , and three genes in the M49 x M48 cross suggests that at least one parent in the G2 x G6 cross have the same or closely linked genes as a parent in the M49 x M48 cross. The F1 means of the five-parent cross (FPC) involving either susceptible parent had lower disease scores, though not significantly (P > 0.05), than the single-crosses from that parent. The F2 of both FPC showed less disease than the single-cross (SC) means (P < 0.05) compared to the single-cross (SC) while the F2 of both FPC had a significant negative deviation (P < 0.05). The F2 frequency distributions also showed that the FPC in both Kanyebwa and K20 populations had higher proportions of resistant plants than any of the single crosses in the respective populations. The superior performance of the FPC over the SC demonstrates that combining resistance genes form different FRR resistance sources can provide a stable source of resistance than using single sources of resistance.
Inheritance of resistance to bacterial blight and implication for rice improvement in Uganda
(RUFORUM, 2010) Habarurema, I.; Asea, G.; Lamo, J.; Gibson, P.; Edema, R.
Bacterial blight caused by Xanthomonas oryzae pv.oryzae, is a destructive disease of rice worldwide. Resistant varieties are the best option to avert the disease. Thirty resistance genes identified face a wide genetic diversity exhibited by the pathogen. Information on local isolates is not available and genetic mechanism for resistance harbored in Ugandan germplasm is unknown. Experimental sites were Makerere University and NaCRRI. Differential cultivars from Africa Rice were used to group Ugandan isolates. Seven parents were crossed into a half diallel to produce F1 and F2 progenies for determining the inheritance of resistance through inoculation. Preliminary results are reported.
Pests and diseases on cowpea in Uganda: Experiences from a diagnostic survey
(African Crop Science Journal, 1999) Adipala, E.; Omongo, C.A.; Sabiti, A.; Obuo, J.E.; Edema, R.; Bua, B.; Atyang, A.; Nsubuga, E.N.; Ogenga-latigo, M.W.
A diagnostic survey (DS) using a questionnaire covering 525 farm households was conducted in 1993/94 to determine the status of cowpea (Vigna unguiculata L. Walp) and its production constraints in Uganda. Subsequent on-farm assessments were made during the two rainy seasons of 1994 to verify and quantify the survey information. Additionally, on-station trials were conducted to address issues arising from the information. Insect pests, low plant population densities, poor weed management and labour bottlenecks are the most important constraints to cowpea production in Uganda. Insect pest damage, particularly by bruchids, is most important. Research to develop integrated pest management (IPM) strategies based on the finding of this study are in progress.
Potential for yield loss reduction and profitability assessment of pesticide control of groundnut leaf miner among soybean genotypes
(African Journals Online (AJOL), 2019-05-17) Namara, M.; Karungi, J.; Edema, R.; Gibson, P.; Tukamuhabwa, P.
Groundnut leaf miner (GLM) is currently a threat to soybean production in Uganda due to the great yield losses as a result of the severe damage it causes on leaves leading to reduced photosynthetic area. GLM is a fairly new pest on soybean in Uganda, having initially been observed in soybean fields in 2011 in eastern Uganda. The objective of this study was to determine the yield loss caused by the groundnut leaf miner and effectiveness and profitability of commonly used pesticides for the control of the groundnut leaf miner (Aproaerema modicella Deventer) (GLM), when tested with popular soybean (Glycine max) genotypes grown in Uganda. In a split plot RCBD design, pesticide protection (treated vs. untreated) formed the main plots; and six commercial soybean varieties (Maksoy 1N, 2N, 3N, 4N, 5N; and Namsoy 4M) as subplots. The study was done in two locations in eastern Uganda (Iki Iki District Agricultural Training and Information Centre (Iki Iki DATIC) and National Semi-Arid Resources Research Institute, Serere (NaSARRI) with two planting rounds at Iki Iki. These sites were chosen because they are hot spots for GLM. GLM severity and soybean yield were significantly affected by the pesticide protection. Overall, percentage grain yield losses caused by GLM on the different soybean varieties ranged from 37.3% to 65.7% and the highest loss was displayed by Maksoy 5N. Grain yield loss recorded at Iki Iki DATIC (53.1%) was remarkably higher than that recorded at the NaSARRI (49.1%). Economic analysis showed marginal returns to be dependent on location, with the Iki Iki DATIC having 0.6 and NaSARRI 1.1. This study has shown that the groundnut leaf miner, a recently emergent pest of soybean is becoming a big threat to soybean production and that chemical control alone may not be economical in managing the pest.
Potential sources of high iron and zinc content in Ugandan bean germplasm
(RUFORUM, 2012) Mukamuhirwa, F.; Tusiime, G.; Mukankusi, C.; Gibson, P.; Edema, R.
The study was conducted at National Agricultural Research Laboratories (NARL) at Kawanda in order to identify potential sources of high iron and zinc content, Such varieties would contribute to improved health of bean (Phaseolus vulgaris) consumers, who, despite a high consumption of beans, suffer from anemia caused by micronutrient malnutrition (especially iron and zinc). One hundred and eighty seven genotypes from Uganda were screened for iron (Fe) and zinc (Zn) content. The mineral analysis revealed that there was significant (P=0.001) diversity in Fe and Zn content among the Ugandan genotypes with the range of 45 to 87mg/kg of iron and 22 to 40 mg/kg of zinc. Ten Ugandan bean varieties were identified as potential sources of both high iron and zinc content.
Prevalence of Angular Leaf Spot Disease and Sources of Resistance in Common Bean in Eastern Democratic Republic Of Congo
(African Crop Science Journal, 2017) Kijana, R.; Abang, M.; Edema, R.; Mukankusi, C.; Buruchara, R.
Angular leaf spot (Pseudocercospora griseola Crous U, Brown) is one of the most important diseases hindering common bean (Phaseolus vulgaris L.) production in the Great Lakes Region of Africa, including the Democratic Republic of Congo. The disease causes extreme yield losses, estimated at 384.2 tonnes per year, in Sub-Saharan Africa. Little is known about the distribution, severity and incidence of the disease and the effect of agronomic practices and environmental factors on the disease prevalence in the country to facilitate interventions. A field survey was conducted during two crop seasons, February to June and September to January, in two main beans growing zones of eastern DRC namely; sub-humid highland and sub-humid mid altitude at low latitudes, in South and North Kivu, respectively. Severity and incidence of angular leaf-spot and other occurring diseases were assessed on common bean plants in farmers’ fields. Angular leaf spot in these fields had an average severity index (PSI) of 49.9%. PSI was significantly different (P<0.05) between districts and seasons. Using multiple regression analysis, independent variables: growth stage, cropping system, districts and altitude were shown to have significant influence on the observed PSI (P<0.05) with R2 = 96.2%. The highest severity (PSI=59.7%) was observed in Kabare district, and the lowest in Uvira district (PSI=39.5%). Screening of a set of 37 released common bean varieties in DRC using virulent Andean and Mesoamerican isolates identified four resistant bean varieties; ARA 4, COD MLV 059, MLV 224/94B, LSA 144 and Mexico 54. Some of these varieties possess useful traits, in addition to acceptable seed market class, and are hence recommended as suitable parents for ALS resistant variety development and promotion in ALS prone environments
Prevalence of viruses infecting cowpea in Uganda and their molecular detection
(African Journal of Biotechnology, 2012-01-26) Amayo, R.; Arinaitwe, A. B.; Mukasa, S. B.; Kyamanywa, S.; Rubaihayo, P. R.; Edema, R.
The main areas for cowpea cultivation in Uganda were surveyed in June and October 2006 for viruses affecting the crop. Seed and leaf samples from symptomatic and asymptomatic plants were collected from farmers’ fields and analysed for infecting viruses using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). The viruses detected in the leaf and seed samples were: cucumber mosaic cucumovirus (CMV), cowpea mild mottle calarvirus (CPMMV), cowpea mottle carmovirus (CPMoV), Cowpea chlorotic mottle bromovirus (CCMV), Cowpea yellow mosaic comovirus (CYMV), cowpea severe mosaic comovirus (CPSMV), cowpea aphid-borne mosaic potyvirus (CABMV) and Southern bean mosaic sobemovirus (SBMV). CPMV was detected only in leaf samples. CMV and CABMV were later confirmed using reverse transcription polymerase chain reaction (RT-PCR). Of the viruses detected in leaf samples, 53.26% occurred as single infections, 24.46% dual and 22.28% multiple infections. Similarly, analysis of seed samples revealed infection of 40.6, 34.6 and 24.8% for single, dual and multiple infections, respectively. Multiple virus infections were associated with more disease severity and higher yield losses. The seed transmission levels of 23.0, 20.3 and 16.4% were recorded for CMV, CPMMV and CABMV, respectively. This study identified six more viruses in addition to what was previously reported in the country, of which eight were seed-borne. This necessitates the need for the production and use of virus-free seeds, development of virus resistant genotypes and adoption of efficient seed certification systems.
Reaction of upland rice genotypes to the brown spot disease pathogen Bipolaris oryzae
(African Journal of Rural Development (AFJRD), 2017) Mwendo, M. M.; Ochwo-Ssemakula, M.; Lamo, J.; Gibson, P.; Edema, R.
Low yields in rice (Oryza sativa L.) are attributed to several factors but diseases represent one of the main constraints. The Brown spot disease (caused by Bipolaris oryzae (Breda de Haan) Shoem) in most cases causes considerable losses in rice growing areas. These yield loses could be averted through development and deployment of resistant varieties. In this study, a field experiment was conducted at the National Crops Resources Research Institute (NaCRRI) – Namulonge, Uganda during 2013 with the objective of identifying new sources of resistance to brown spot disease. Among the 100 tested rice lines, 18 lines were rated as highly resistant, 52 resistant, 27 moderately resistant and three lines including the checks were susceptible. The results revealed that there was significant variation in brown spot resistance among the genotypes tested. The identified resistant lines will be utilized in rice breeding program in Uganda for development of brown spot resistant genotypes.

Browsing by Author "Edema, R."

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