Person: Otim, M.
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Otim
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M.
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Otim, M.
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0000-0001-5406-012X 10 results
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- Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda(Elsevier, 2022) Otim, M.; Alibu. S.; Asea, G.; Abalo, G.; Sserumaga, J.P.; Adumo, S.; Alupo, J.; Ochen, S.; Tadele Tefera; Bruce, A.Y.; Beyene, Y.; Meisel, B.; Tende, R.; Nang’ayo, F.; Baguma, Y.; Mugo, S.N.; Oikeh, S.O.
Publication - Phenotypic and genotypic variation in tropical maize inbred lines for resistance to the maize weevil and larger grain borer(Transstellar Journal Publications, 2012) Mwololo, J.; Okori, P.; Mugo, S.N.; Tadele Tefera; Beyene, Y.; Otim, M.; Munyiri, S.W.
Publication - Evaluation of early-generation tropical maize testcrosses for grain-yield potential and weevil (Sitophilus zeamais Motschulsky) resistance(Elsevier, 2021) Sserumaga, J.P.; Makumbi, D.; Oikeh, S.O.; Otim, M.; Machida, L.; Bruce, A.Y.; Nhamucho, E.; Beyene, Y.; Mugo, S.N.
Publication - Quantitative trait loci mapping in maize for resistance to larger grain borer(Consiglio per la Ricerca e la Sperimentazione in Agricoltura, 2018) Mwololo, J.; Mugo, S.N.; Otim, M.; Munyiri, S.W.; Okori, P.Storability of maize grain is constrained by the larger grain borer (LGB) (Prostephanus truncatus). Host plant resistance is the most feasible way to manage LGB among smallholder farmers. Breeding for resistance to this pest in maize is dependent on understanding genetic mechanisms underlying the resistance. The objective of this study was to map quantitative trait loci (QTL) associated with LGB resistance in tropical maize. A mapping population of 203 F2:3 derived progenies was developed from a cross between susceptible and resistant inbred lines. The F2:3 progenies were crossed to a tester and testcrosses evaluated across six environments followed by screening for resistance to LGB. Data was collected on husk cover tip length, and grain texture in the field. Biochemical traits were analyzed on the maize grain. Harvested grain was evaluated for resistance and data recorded on grain damage, weight loss and number of insects. Grain hardness was measured as a putative trait of resistance. Univariate analysis of variance for all the traits was done using the general linear model of statistical analysis system. Genetic mapping was done using Joinmap 4, while QTL analysis was done using PLABQTL. The QTL for resistance were mapped to 6 out of the 10 chromosomes. QTL for resistance traits were located in chromosomes 1, 5 and 9. Chromosome 1 had a common QTL linked to protein content, grain hardness and husk cover tip length. Additive genetic effects were prevalent in all detected QTL. Overall, the studies show that breeding for resistance to LGB is possible.
Publication - Grain-yield stability among tropical maize hybrids derived from doubled-haploid inbred lines under random drought stress and optimum moisture conditions(CSIRO, 2018) Sserumaga, J.P.; Beyene, Y.; Pillay, K.; Alois Kullaya; Oikeh, S.O.; Mugo, S.N.; Machida, L.; Ismail Ngolinda; Asea, G.; Justin Ringo; Otim, M.; Abalo, G.; Barnabas KiulaDrought is a devastating environmental stress in agriculture and hence a common target of plant breeding. A review of breeding progress on drought tolerance shows that, to a certain extent, selection for high yield in stress-free conditions indirectly improves yield in water-limiting conditions. The objectives of this study were to (i) assess the genotype × environment (GE) interaction for grain yield (GY) and other agronomic traits for maize (Zea mays L.) across East African agro-ecologies; and (ii) evaluate agronomic performance and stability in Uganda and Tanzania under optimum and random drought conditions. Data were recorded for major agronomic traits. Genotype main effect plus GE (GGE) biplot analysis was used to assess the stability of varieties within various environments and across environments. Combined analysis of variance across optimum moisture and random drought environments indicated that locations, mean-squares for genotypes and GE were significant for most measured traits. The best hybrids, CKDHH1097 and CKDHH1090, gave GY advantages of 23% and 43%, respectively, over the commercial hybrid varieties under both optimum-moisture and random-drought conditions. Across environments, genotypic variance was less than the GE variance for GY. The hybrids derived from doubled-haploid inbred lines produced higher GY and possessed acceptable agronomic traits compared with the commercial hybrids. Hybrid CKDHH1098 ranked second-best under optimum-moisture and drought-stress environments and was the most stable with broad adaptation to both environments. Use of the best doubled-haploids lines in testcross hybrids make-up, well targeted to the production environments, could boost maize production among farmers in East Africa.
Publication - Correction to: genotype by environment interactions and agronomic performance of doubled haploids testcross maize (Zea mays L.) hybrids(Springer, 2018) Sserumaga, J.P.; Oikeh, S.O.; Mugo, S.N.; Asea, G.; Otim, M.; Beyene, Y.; Abalo, G.; Kikafunda, J.
Publication - Maize combined insect resistance genomic regions and their co-localization with cell wall constituents revealed by tissue-specific QTL meta-analyses(Frontiers, 2018) Badji, A.; Otim, M.; Machida, L.; Odong, T.; Kwemoi, D.B.; Okii, D.; Agbahoungba, S.; Mwila, N.; Kumi, F.; Ibanda, A.; Mugo, S.N.; Kyamanywa, S.; Rubaihayo, P.Combinatorial insect attacks on maize leaves, stems, and kernels cause significant yield losses and mycotoxin contaminations. Several small effect quantitative trait loci (QTL) control maize resistance to stem borers and storage pests and are correlated with secondary metabolites. However, efficient use of QTL in molecular breeding requires a synthesis of the available resistance information. In this study, separate meta-analyses of QTL of maize response to stem borers and storage pests feeding on leaves, stems, and kernels along with maize cell wall constituents discovered in these tissues generated 24 leaf (LIR), 42 stem (SIR), and 20 kernel (KIR) insect resistance meta-QTL (MQTL) of a diverse genetic and geographical background. Most of these MQTL involved resistance to several insect species, therefore, generating a significant interest for multiple-insect resistance breeding. Some of the LIR MQTL such as LIR4, 17, and 22 involve resistance to European corn borer, sugarcane borer, and southwestern corn borer. Eleven out of the 42 SIR MQTL related to resistance to European corn borer and Mediterranean corn borer. There KIR MQTL, KIR3, 15, and 16 combined resistance to kernel damage by the maize weevil and the Mediterranean corn borer and could be used in breeding to reduce insect-related post-harvest grain yield loss and field to storage mycotoxin contamination. This meta-analysis corroborates the significant role played by cell wall constituents in maize resistance to insect since the majority of the MQTL contain QTL for members of the hydroxycinnamates group such as p-coumaric acid, ferulic acid, and other diferulates and derivates, and fiber components such as acid detergent fiber, neutral detergent fiber, and lignin. Stem insect resistance MQTL display several co-localization between fiber and hydroxycinnamate components corroborating the hypothesis of cross-linking between these components that provide mechanical resistance to insect attacks. Our results highlight the existence of combined-insect resistance genomic regions in maize and set the basis of multiple-pests resistance breeding.
Publication - Genotype by environment interactions and agronomic performance of doubled haploids testcross maize (Zea mays L.) hybrids(Springer, 2016) Sserumaga, J.P.; Oikeh, S.O.; Mugo, S.N.; Asea, G.; Otim, M.; Beyene, Y.; Abalo, G.; Kikafunda, J.In vivo production of maternal haploid plants and advancement in chromosome doubling technology has led to rapid production of doubled haploid homozygous lines. These in turn have boosted rapid advancement in most breeding programs. This has resulted in production of a large number of maize hybrids which need testing across production environments to select the most suitable hybrids for release and cultivation. The objective of this study was to assess the genotype 9 environment interactions (GE) for grain yield and other agronomic traits and evaluate the performance of 44 recently developed doubled haploids (DH) testcross hybrids along with six checks across five locations in Uganda. Significant mean squares for environment (E), genotype (G) and GE were observed for all studied traits. Environment explained 46.5 % of the total variance, while G and GE contributed 13.2 and 7.2 %, respectively. Genetic correlations among locations were high (0.999), suggesting little GE among environments. The 10 best testcross hybrids had a 49.2 %average grain yield advantage over the six checks at all locations. DH hybrids CKHDHH0887, CKDHH0878, CKDHH 0859, WM1210, CKDHH0858, and WM1214 were the most stable, across locations. The DH testcross hybrids produced higher grain yield and possessed acceptable agronomic traits compared to the commercial hybrids developed earlier. Use of the best DH testcross hybrids, well targeted to the production environments, could boost maize production among farmers.
Publication - Responses of tropical maize landraces to damage by Chilo partellus stem borer(Academic Journals, 2013) Munyiri, S.W.; Mugo, S.N.; Otim, M.; Tadele Tefera; Beyene, Y.; Mwololo, J.; Okori, P.The potential to manage insect pests using host-plant resistance exists, but has not been exploited adequately. The objective of this study was to determine the resistance of 75 tropical maize landraces through artificial infestation with Chilo partellusSwinhoe. The trial was laid in alpha-lattice design and each seedling was infested with five neonates three weeks after planting, over two seasons in 2009 and 2010. The number of exit holes, tunnel length, ear diameter, ear length, plant height, stem diameter, stem lodging and grain yield were measured and a selection index computed. GUAT 1050 was the most resistant with an index of 0.56, while BRAZ 2179 was the most susceptible with an index of 1.66. Ear characteristics were negatively correlated with damage parameters. The principal component biplot suggested that exit holes, cumulative tunnel length, leaf damage, cob diameter, stem lodging, selection index, ear and plant height contributed 71.2% of the variation in resistance. The mean number of exit holes and tunnel length for resistant landraces and resistant hybrid checks were similar; at 5.5 and 2.48 cm, respectively. The identified resistant landraces (GUAT 1050, GUAT 280, GUAT 1093, GUAT 1082, GUAT 1014, CHIS 114, and GUAN 34) could be used to develop C. partellus stem borer-resistant maize genotypes.
Publication - Sources of resistance to the maize weevil Sitophilus Zeamais in tropical maize(Canadian Center of Science and Education, 2012) Mwololo, J.; Mugo, S.N.; Okori, P.; Tadele Tefera; Otim, M.; Munyiri, S.W.The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is among the major storage pests that enhance food insecurity among maize farmers. New sources of resistance to the maize weevil are critical in a successful breeding program to address grain damage by postharvest pests. The objective of the study was to evaluate resistance in maize genotypes to the maize weevil, and consequently their value for use in breeding programs. A total of 175 genotypes, including hybrids, landraces, open-pollinated varieties and checks, were tested for resistance to the maize weevil. The percentage grain damage, weight loss, flour weight and weight of damaged and undamaged grains were measured. Significant differences (P <0.001) were observed among the genotypes for all the traits evaluated. The distribution of the genotypes among the different categories of resistance was an indication of the existence of genetic variation. The most resistant genotypes were CKPH08003 and BRAZ 2451 while the most susceptible were PH 3254 and BRAZ 4, among the hybrids and landraces respectively. Genotypes that were superior to the resistant checks were identified. The percentage weight loss and flour weight were identified as the most important insect-resistance traits for discriminating genotypes as evident from the canonical discriminant analysis. Correlation coefficients among the traits evaluated were highly significant. The resistant hybrids identified can be recommended for release and adoption by farmers, whereas the resistant landraces can act as sources of resistance for use in breeding programs.
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