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Otim, M.

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Otim
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Otim, M.

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Now showing 1 - 6 of 6
  • 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
  • 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
  • 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
  • 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.
    Publication