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Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition
Dissertation (M Inst Agrar (Horticulture))--University of Pretoria, 2007.
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University of Pretoria
2013
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| _version_ | 1867613551521169408 |
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| access_status_str | Open Access |
| author2 | Botha, Christelle Charle |
| author_browse | Botha, Christelle Charle |
| author_facet | Botha, Christelle Charle |
| collection | Thesis |
| dc_rights_str_mv | © 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (M Inst Agrar (Horticulture))--University of Pretoria, 2007. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/27896 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:56.779Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/27896 Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition Botha, Christelle Charle Soundy, Puffy lmadzivhandila@arc.agric.za Madzivhandila, Livhuwani Lilly-Rose Cultivars Nitrogen Transplants Lettuce UCTD Dissertation (M Inst Agrar (Horticulture))--University of Pretoria, 2007. Experiments were conducted with lettuce at the field and in the glasshouse at the Hatfield Experimental Farm, University of Pretoria. The objectives of the study were to evaluate the performance of selected crisphead lettuce cultivars in relation to yield and quality performance and to investigate which level of nitrogen can produce high quality transplants. In the lettuce cultivar trial, fifteen crisphead lettuce cultivars were grown, during March to May 2004. The experiment was laid out as a randomised complete block design with four replications. At harvest, the centre 20 plants were cut for yield determination and five uniform plants were then cut longitudinally for head quality characteristics. For each cultivar, compactness and uniformity were also evaluated and the number of days to maturity was recorded. Among the cultivars tested, the best yielding cultivars were Dual Purpose (46.8 t•ha-1), Great Lakes (45.8 t•ha-1), Mohawk (44.3 t•ha-1) and Victory (43.9 t•ha-1). Poor yielding cultivars were Taina (30.5 t•ha-1), Cannon (31.5 t•ha-1), Summer Time (32.1 t•ha-1) and Classic (33.2 t•ha-1). Del Rio was the best disease resistant cultivar, producing 100% marketable heads. All cultivars tested had good compactness and uniformity with the exception of Great Lakes 659. Early-maturing cultivars were ready 60 days after transplanting. Seeds of the lettuce cultivar ‘Aviram’ were sown, in the nitrogen nutrition of lettuce transplant’s trial. Two days after seeding, the seedlings were fertigated every second day by floating the trays in the plastic-lined tubs containing nutrient solution at 0, 30, 60,90 and 120 mg•L-1 N until field capacity was reached. Transplants produced with 0 N grew poorly, regardless of the sampling date. Nitrogen at 120 mg• L-1 improved the response of shoot growth, plant height and leaf area, but adversely affected root growth. In general, relative growth rate was improved while net assimilation rate was reduced as N level increased. Root: shoot ratio decreased with applied N. The largest values of root: shoot ratio were obtained with 0 N. Both specific leaf area and leaf area ratio increased with applied N. Leaf mass ratio improved, while root mass ratio was reduced as N levels increased. At 35 days after sowing, leaf tissue N increased from 0.43 to 4.15 mg•kg-1 with N applied. Only 25% of the plants produced without N could be pulled from the seedling trays, whereas 90% could be pulled when 90 mg•L-1 N was added. This work suggested that at least 90 mg•L-1N, supplied via floatation irrigation was required to produce a transplant with sufficient roots for ease of pulling. Applying 90 mg•L-1 N, resulted in improved root and shoot growth, resulting in high quality transplants. Plant Production and Soil Science unrestricted 2013-09-07T12:34:12Z 2006-02-10 2013-09-07T12:34:12Z 2005-08-03 2007-02-10 2006-02-10 Dissertation Madzivhandila, L 2005, Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition, M dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/27896 > http://hdl.handle.net/2263/27896 http://upetd.up.ac.za/thesis/available/etd-02102006-154918/ © 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Cultivars Nitrogen Transplants Lettuce UCTD Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title | Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title_full | Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title_fullStr | Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title_full_unstemmed | Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title_short | Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition |
| title_sort | crisphead lettuce lactuca sativa l cultivar evaluation and response of transplants to nitrogen nutrition |
| topic | Cultivars Nitrogen Transplants Lettuce UCTD |
| url | http://hdl.handle.net/2263/27896 http://upetd.up.ac.za/thesis/available/etd-02102006-154918/ |