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Triploid induction in the South African abalone, Haliotis midae
Bibliography: leaves 72-80.
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2014
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| _version_ | 1867613342267342848 |
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| access_status_str | Open Access |
| author | Stepto, Nigel Keith |
| author2 | Cook, Peter |
| author_browse | Cook, Peter Stepto, Nigel Keith |
| author_facet | Cook, Peter Stepto, Nigel Keith |
| author_sort | Stepto, Nigel Keith |
| collection | Thesis |
| description | Bibliography: leaves 72-80. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/9669 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:34:36.552Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/9669 Triploid induction in the South African abalone, Haliotis midae Stepto, Nigel Keith Cook, Peter Zoology Bibliography: leaves 72-80. An investigation was undertaken to determine whether triploidy could be induced and improve the growth rate of the South African abalone, Haliotis midae. From the polar body counts at 17 °C the release times of polar body 1 and 2 were found to be at 12 - 15 min. post insemination (pi.) and 33-36 min. pi. respectively. Cytochalasin B (CB) (0.5mg. 1-¹ seawater) and elevated temperature (30 °C) were used as stresses to induce triploidy. CB induced 48.4% polar body 1 and 70.9 % polar body 2 triploid larvae at 20 hrs pi. At 120 hrs pi. induction rates were 55.5% and 62.4% respectively. Temperature induction was more successful, producing 92.9% polar body 1 and 86.4% polar body 2 triploid larvae at 20 hrs pi. This success was still evident at 120 hrs pi, where 71.1 % polar body 1 and 62.5% polar body 2 triploid larvae were produced. In the CB induction, where polar body 1 was retained, there was a pronounced production of tetraploid larvae (34. 2%). It appeared that CB affected the ova's resistance to polyspermy, which was found to be dependent on both CB concentration and the amount of excess sperm present. At 0.4 mg 1-¹ CB in seawater, 86.5% triploids and 0% tetraploids were produced. However, on the addition of sperm, 25.4% triploids and 69% tetraploids resulted. CB (0.5 mg 1-¹ ) in seawater produced 42.6%> tetraploids which, after the addition of sperm, increased even further to 50. l % pentaploids. Larval survival was found to be low overall with only 17% and 22% of control (diploid) animals surviving the rearing period, in the temperature and CB treatments respectively. The survival rates of the polar body 2 treatment were 11 % and 15% whilst those of the polar body 1 treatment were 7% and 11 %. Although these percentages indicated a difference in survival rates between the CB and temperature inductions, the actual numbers of larvae surviving were the same. The polar body 1 triploid larval survival was significantly less than both control and polar body 2 triploid animals. 2014-11-15T19:43:48Z 2014-11-15T19:43:48Z 1997 Master Thesis Masters MSc http://hdl.handle.net/11427/9669 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Zoology Stepto, Nigel Keith Triploid induction in the South African abalone, Haliotis midae |
| thesis_degree_str | Master's |
| title | Triploid induction in the South African abalone, Haliotis midae |
| title_full | Triploid induction in the South African abalone, Haliotis midae |
| title_fullStr | Triploid induction in the South African abalone, Haliotis midae |
| title_full_unstemmed | Triploid induction in the South African abalone, Haliotis midae |
| title_short | Triploid induction in the South African abalone, Haliotis midae |
| title_sort | triploid induction in the south african abalone haliotis midae |
| topic | Zoology |
| url | http://hdl.handle.net/11427/9669 |
| work_keys_str_mv | AT steptonigelkeith triploidinductioninthesouthafricanabalonehaliotismidae |