Sorghum resistance to the sugarcane aphid (Homoptera:Aphididae) /
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1992.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Four hundred and sixty-four sorghum lines were screened for resistance to sugarcane aphid, Melanaphis sacchari (Zehntner) (Homoptera:Aphididae), in greenhouse tests at Sebele, Botswana and Matopos, Zimbabwe. Forty-one lines had low plant damage and aphid abundance ratings and included 28 converted lines from the Texas A&M University sorghum entomology/breeding program, six breeding lines from the Southern Africa Development Coordination Conference/International Crops Research Institute for the Semi-Arid Tropics (SADCC/ICRISAT) program, and seven locally used cultivars from Zimbabwe. In Botswana, TAM428 and IS12661C were determined highly resistant; and IS12609C, IS12610C, and IS12664C were moderately resistant. In Zimbabwe, TAM428, IS12661C, IS12609C, and IS12664C were highly resistant and IS12610C was moderately resistant. Differential host plant reaction was noted for IS12610C, IS12609C, and IS12664C sorghum lines for the Botswana and Zimbabwe sugarcane aphid populations. Four sorghum lines: SA1221, SA1469, SA1470, and SA1471, from South Africa also were confirmed resistant to sugarcane aphid in Botswana and Zimbabwe. High levels of antixenosis were found for TAM428, IS12609C, IS12661C, IS12664C, IS1144C, and SC464 sorghum lines. In addition, TAM428, IS12609C, IS12661C, IS12664C, SA1221, and SA1469 had high levels of antibiosis as seedling and mature plants. Low levels of antibiosis and tolerance to aphid feeding were found in sorghum lines IS12637C, IS6264C, and IS12610C. Aphid mortality was high and fecundity low on resistant sorghum lines in greenhouse and field tests. Aphids did not establish field infestations on TAM428 sorghum, the resistant check, but established high infestation levels on 'Segaolane', the susceptible check, under similar field conditions. These data confirmed the availability of plant resistance to sugarcane aphid populations on sorghum in Botswana and Zimbabwe. The F1 generations of crosses between resistant (TAM428, SC170) and susceptible (Tx378, ATx3048) parents were resistant, but susceptible for moderately resistant (SC110) by susceptible (Tx378, ATx3048) parents. F2 generations of crosses between resistant (TAM428, SC170) and susceptible (SC120, Tx378) parental lines segregated in a 3:1 ratio (resistant:susceptible), indicating that resistance was inherited as a dominant and monogenic character. The data indicated the presence of additional modifying factors conditioning resistance. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Entomology." |
| Physical Description: | xii, 116 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |