1,720,991 research outputs found
Effect of inoculation method and plant growth medium on endophytic colonization of sorghum by the entomopathogenic fungus Beauveria bassiana
No full textA study was conducted to determine the effect of inoculation method and plant growth medium on colonization of sorghum by an endophytic Beauveria bassiana. Colonization of leaves, stems, and roots by B. bassiana was assessed 20-days after application of the fungus. Although B. bassiana established as an endophyte in sorghum leaves, stems, and roots regardless of inoculation method (leaf, seed, or soil inoculation), plant growth medium (sterile soil, non-sterile soil, or vermiculite) apparently influenced colonization rates. Seed inoculation with conidia caused no stem or leaf colonization by the fungus in non-sterile soil but did result in substantial endophytic colonization in vermiculite and sterile soil. Leaf inoculation did not result in root colonization, regardless of plant growth medium. Endophytic colonization was greater in leaves and stems than roots. Endophytic colonization by B. bassiana had no adverse effects on the growth of sorghum plants. Leaf inoculation with a conidial suspension proved to be the best method to introduce B. bassiana into sorghum leaves for plants growing in either sterile or non-sterile soil. Further research should focus on the virulence of endophytic B. bassiana against sorghum stem borers.Alexander von Humboldt Foundation, Bon
Importance of husk covering on field infestation of maize by Sitophilus zeamais Motsch (Coleoptera: Curculionidea) at Bako, Western Ethiopia
No full textAn experiment was conducted to determine the importance of husk covering on field infestation of maize by the maize weevil, Sitophilus zeamais, at Bako, western Ethiopia. Five maize genotypes, G1 (SZSYNA99- F2 -33-4-2 X SC22), G2 (CML-197 X SZSYNA99- F2 -33-4-1), G3 (SZSYNA99-F2 -79-4-3 X CML- 197), G4 (BH-140) and G5 (Bukuri) were used. There were differences among the maize genotypes in their resistance to the maize weevil. The genotypes, G2, G3 and G5 had good husk characteristics (extended tip and tight husk) and flint grains resulted in low number of weevils and damaged ears. On the contrary, the genotype G1, with dent-flint-grain, poor husk characteristics (bare tipped and loose husk cover), harbored the highest number of weevils and suffered ear damage followed by the genotype, G4. Therefore, husk tip extension and husk tightness were the two most important characters conferring resistance to maize ears against the maize weevil in the field
Importance of husk covering on field infestation of maize by Sitophilus zeamais Motsch (Coleoptera: Curculionidea) at Bako, Western Ethiopia
No full textAn experiment was conducted to determine the importance of husk covering on field infestation of maize by the maize weevil, Sitophilus zeamais, at Bako, western Ethiopia. Five maize genotypes, G1 (SZSYNA99- F2 -33-4-2 X SC22), G2 (CML-197 X SZSYNA99- F2 -33-4-1), G3 (SZSYNA99-F2 -79-4-3 X CML- 197), G4 (BH-140) and G5 (Bukuri) were used. There were differences among the maize genotypes in their resistance to the maize weevil. The genotypes, G2, G3 and G5 had good husk characteristics (extended tip and tight husk) and flint grains resulted in low number of weevils and damaged ears. On the contrary, the genotype G1, with dent-flint-grain, poor husk characteristics (bare tipped and loose husk cover), harbored the highest number of weevils and suffered ear damage followed by the genotype, G4. Therefore, husk tip extension and husk tightness were the two most important characters conferring resistance to maize ears against the maize weevil in the field
Efficacy of combining Niger seed oil with malathion 5% dust formulation on maize against the maize weevil, Sitophilus zeamais (Coleoptera: Curculionidae)
No full textThe combined effects of Niger seed oil and malathion, 5% dust, against the maize weevil, Sitophilus zeamais, were evaluated to determine the minimum effective rate(s) of the combinations that can provide adequate protection to maize seed against attack by weevils. Niger seed oil at the rates of 0%, 10%, 20%, 30%, 40%, 50% and 100% of the recommended application rate, 5 ml kg(-1), was combined with malathion at the respective rates of 100%, 50%. 40%. 30%, 20%, 10% and 0% of the recommended application rate, 0.5 g kg(-1). All combinations provided complete protection to maize seed from the maize weevil up to 90 days after infestation. To determine the residual effects of the treatments, weevils were reintroduced to the grain that had been treated 90 days previously. In addition to 100% malathion, 10% Niger seed oil+50% malathion, and 20% Niger seed oil+40% malathion, were fully effective in controlling S. zeamais for a further 156 days after this re-infestation. Therefore, these combinations could be considered as a potential component in an effort to establish integrated management of the maize weevil. Residual performance of both oil and malathion against the weevils was primarily affected by the dose of malathion, with higher doses of malathion providing greater protection for a longer period. Niger seed oil treatment lowered the level of seed germination at the application rate of 5 ml per kg of maize. (C) 2008 Published by Elsevier Ltd
Resistance of maize varieties to the maize weevil Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae)
No full textThis 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
Biology of barley shoot fly Delia flavibasis Stein (Diptera: Anthomyiidae) on resistant and susceptible barley cultivars
Full text linkThe biology of barley shoot fly Delia flavibasis was studied using resistant (Dinsho and Harbu) and susceptible (Holker) barley cultivars at Sinana Agricultural Research Center, Ethiopia. A higher number of eggs was laid on Holker (17 eggs/female) than on Dinsho (11 eggs/female) or Harbu (12 eggs/female). However, there were no differences between cultivars in preoviposition and total reproductive periods. The shortest time required to complete larval, pupal and total developmental stages from egg to adult emergence occurred when the insect was reared on the cultivar Holker. Pupal weight, adult emergence and adult longevity did not differ between cultivars. The female to male sex ratio was 1:1. This study enabled us to understand the duration of each of the life stages of D. flavibasis, which will undoubtedly aid researchers and growers to design a sustainable management strategy against barley shoot fly
Proceedings of the Annual Review Meeting of Rice, Maize and Chickpea IPM for East Africa Project, Hawassa, Ethiopia 17-18 July , 2017
No full textThe purpose of the annual review meeting was to review the status of the project in the first year, to exchange the challenges, achievements and to discuss on the way forward. The meeting was also giving an opportunity to introduce the staff working under rice, maize and chickpea IPM project and to bring synergies together, and adhere to the goals of the project.USAI
Distribution and mating type characterization of chickpea blight (Didymella rabiei (Kov.) v. Arx) in Ethiopia
No full textWe have assessed the distribution and mating type of chickpea blight (Didymella rabiei (Kov.) v. Arx) from a total of 350 and 272 fields in major chickpea (Cicer arietinum L.) growing areas of Ethiopia for two consecutive cropping seasons 2017 and 2018, respectively. The prevalence of D. rabiei was 20 % for the year 2017 and 7% for 2018. Severity range of 2−9 and incidence of 10–100 % were recorded for both seasons in only 7–20 % of the assed fields. Field prevalence of 2017 and 2018 seasons were significantly different (df = 31; p < 0.001 and df = 31; p < 0.001, respectively). Similarly, the disease prevalence of both seasons was significantly different (df = 31; p < 0.001). The disease prevalence ratio frequency was highly deviated from (1:1) for both seasons (X2 = 213.62 p= <0.001; X2 = 144.36 p = 0.01). Genomic DNA of Representative samples were extracted from single spore culture and Mating type 1 (MAT1-1) specific primer SP21, Mating type 2 (MAT1-2) specific primer Tail 5, and a flanking region-specific primer Com1 assay were multiplexed in a single PCR reaction to determine the occurrence of D. rabiei mating type in Ethiopia. Out of 156 samples, only 15 samples were positive to MAT1-1 (∼10 %) with the ratio of 9:1. MAT 1−2 type was the most dominant and possibly the asexual reproduction of D. rabiei is the major type in Ethiopia. The result is important for Ascochyta blight management in breeding strategy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
