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" Factors maintaining sorghum (Sorghum bicolor (L.) Moench); landrace diversity in north Shewa and south Welo regions of Ethiopia "
A. Teshome
J. D. H. T. Lambert, J. K.
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1113456
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| Doc. No
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TLpq304235112
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| Main Entry
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A. Teshome
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J. D. H. T. Lambert, J. K.
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| Title & Author
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Factors maintaining sorghum (Sorghum bicolor (L.) Moench); landrace diversity in north Shewa and south Welo regions of Ethiopia\ A. TeshomeJ. D. H. T. Lambert, J. K.
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| College
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Carleton University (Canada)
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| Date
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1996
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| student score
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1996
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| Degree
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Ph.D.
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| Page No
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182
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| Abstract
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Sorghum landrace diversity, ethnobotanical knowledge and the agricultural system in north Shewa and south Welo regions of Ethiopia have been studied to: (1) examine intraspecific variations of Sorghum landraces grown by the farmers and to test the consistency of folk taxonomy; (2) quantify the relationships between Sorghum landrace diversity at the field level and environmental factors (field size, altitude and soil organic matter content, textures and pH) and farmers' selection criteria; and (3) measure the susceptibility of stored-sorghum landraces to Sitophilus oryzae, and compare farmers' knowledge of storability to the laboratory findings of resistance to S. oryzae. Data were collected from 260 randomly selected fields across the study area, including 177 accessions. Each accession was identified by the farmer who indicated why she/he grew that landrace. Fourteen phenotypic characters were chosen for taxonomic classification of these 177 accessions. Multivariate analyses grouped the accessions into three clusters with some linking of phenotypic characters. A botanical key was established. The five most common landraces named by the farmers, which constituted 44 of the accessions, formed dissimilar groups, suggesting that farmers' naming of these Sorghum landraces was consistant. Farmers used the salient morphological characters of juiciness, midrib color, grain color, grain size, glume color, glume hairiness, and grain shape to distinguish the Sorghum landraces. These characters, with the exception of midrib color, were the subset of important morphological characters identified by the numerical taxonomic investigation grouping the landraces into three clusters and confirmed a good agreement between the farmers' folk taxonomy and the numerical taxonomy. Linear and polynomial regressions indicated that Sorghum landrace diversity at the field level had significant relationships with altitude, field, size and farmers' selection criteria. In the polynomial regressions farmers' selection criteria explained 21% of variations, while altitude was 62%. Multiple regression analyses showed that soil pH and clay content along with the terms that were significant in the linear and polynomial regressions, had significant relationships with Sorghum landrace diversity at the field level. Of particular interest is that the diversity increases as the number of farmers' selection criteria increases. This relationship was not a result of the interaction between selection criteria and environmental factors, because the farmers' selection variable was significant after statistically correcting for the effects of environmental variables. The total number of selection criteria applied to individual landraces ranged from one to six, and the number of selection criteria used per field ranged from two to nine. The resistance to S. oryzae of 16 Ethiopian stored-sorghum landraces was measured by usd\rm F\sb1usd emergence, oviposition, weight loss, development period, and Dobie Index. The ANOVA (LSD) multiple range test indicated that the stored-sorghum landraces represented a range of susceptibilities which were significantly different and grouped into 11 and 13 classes based on adult emergence and on oviposited eggs. Comparison with the farmers' consensus index of storability indicated clearly that farmers know the storability of their germplasm. Farmer accuracy was remarkable; R2 values greater than 0.85 were found for several susceptibility parameters.
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Agronomy
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Biological sciences
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Ecology
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Genetics
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Plant pathology
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Sitophilus oryzae
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