Person:
Tadele Tefera

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Tadele Tefera
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Tadele Tefera

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  • 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
  • Testcross performance of doubled haploid maize lines derived from tropical adapted backcross populations
    (Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di Ricerca per la Maiscoltura, 2011) Beyene, Y.; Mugo, S.N.; Pillay, K.; Tadele Tefera; Ajanga, S.; Njoka, S.; Karaya, H.; Gakunga, J.
    Doubled haploid (DH) lines produced by in vivo induction of maternal haploids are routinely used in maize breeding. The present study was carried out to assess the performance of 75 doubled haploid maize testcrosses and six checks tested across four locations in Kenya for grain yield, agronomic traits and reaction to major leaf diseases. The 75 DH lines were derived from the backcross (BC1) plants of two CIMMYT bi-parental crosses. Significant location, genotype and genotype x location effects were observed for grain yield and anthesis-silking interval (ASI). Genotypes were significantly different for reaction to leaf blight and gray leaf spot. Location explained 69% of the total phenotypic variance while both genotype and genotype by environment interaction effects contributed 4% each. Fifteen DH testcross hybrids yielded better than the best commercial check, WH505 (5.1 t/ha). The best DH testcross hybrid (CKDHH0223) averaged over the four locations yielded 29.5% higher than WH505. These results indicate that maize testcrosses developed from DH lines produced as high a grain yield and as acceptable agronomic traits as the commercial hybrids developed through conventional pedigree methods. The DH lines identified in the study may be useful for improving yield and disease resistance in maize breeding programs in eastern and southern Africa.
    Publication
  • Resistance of maize varieties to the maize weevil Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae)
    (Academic Journals, 2009) Abebe, F.; Tadele Tefera; Mugo, S.N.; Beyene, Y.; Vidal, S.
    This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize varieties were screened for their relative susceptibility to S. zeamais. The Dobie index of susceptibility was used to group the varieties. The variety, ?BHQP-542?, had the least index of susceptibility and was regarded as resistant. The varieties, ?Katumani?, ?Melkasa-I?, ?Melkasa-II?, ?Melkasa-III?, ?Coree?, ?BH-541?, ?BH-660?, ?BH-540?, ?Rare-I?, ?Awasa-511?, ?ACV3? and ?ACV6?, were moderately resistant. Weevils fed with the resistant variety produced low numbers of F1 progeny, had a high median developmental time and a low percentage of seed damage and seed weight loss. Maize varieties with a high F1 progeny tended to have a short median developmental time. An increasing number of F1 progeny resulted in an increasing seed damage and seed weight loss. We found an inverse relationship between the susceptibility index and percent mortality and median developmental time; however, the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility index. The use of resistant varieties should be promoted in managing S. zeamais in stored maize under subsistence farming conditions in Africa.
    Publication
  • Methods of screening maize for resistance to stem borers and post-harvest insect pests
    (CIMMYT, 2011) Tadele Tefera; Mugo, S.N.; Tende, R.; Likhayo, P.
    This manual is based on the work undertaken through the “Developing Maize Resistant to Stem Borer and Storage Insect Pests for Eastern and Southern Africa – IRMA III Conventional Project (2009−2013)”, funded by the Syngenta Foundation for Sustainable Agriculture. We would like to acknowledge Dr B.M. Prasanna (Director, Global Maize Program, CIMMYT), for his inputs and guidance during preparation of this manual.
    Publication
  • Mass rearing of stem borers, maize weevil, and larger grain borer insect pests of maize
    (CIMMYT, 2010) Tadele Tefera; Mugo, S.N.; Tende, R.; Likhayo, P.
    Variety screening studies require a consistent supply of large quantities of these pests at specified time periods. Stem borers are reared on an artificial diet in order to have dependable large and continuous supplies of insects for screening plant materials. The stem borer and post-harvest rearing facility has a significant impact on research focused at managing post-harvest insects and maize stem borer populations through host plant resistance. The rearing facility supports national and international research projects aimed at developing maize varieties that can be incorporated in integrated pest management of stem borers and post-harvest pests of maize. This manual will describe the methods used to rear stem borers, maize weevil and larger grain borer in the facilities at KARI - Katumani and KARI - Kiboko, both in Kenya.
    Publication