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The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch)
Dissertation (MScAgric (Horticulture))--University of Pretoria, 2021.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2022
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| _version_ | 1867613504471564288 |
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| access_status_str | Open Access |
| author2 | Taylor, Nicolette Jane |
| author_browse | Taylor, Nicolette Jane |
| author_facet | Taylor, Nicolette Jane |
| collection | Thesis |
| dc_rights_str_mv | © 2022 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 (MScAgric (Horticulture))--University of Pretoria, 2021. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/83752 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:12.164Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| 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:2263/83752 The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) Taylor, Nicolette Jane selulekokunene@gmail.com Annandale, John George Kunene, Seluleko UCTD Horticulture Water stress Phenological stages Dissertation (MScAgric (Horticulture))--University of Pretoria, 2021. An important part of developing sound water management strategies for crops is to identify phenological stages which are sensitive and insensitive to water stress in terms of yield and quality. This is particularly important for regions which are prone to droughts and where water resources are limited. As pecans are largely produced in semi-arid regions in South Africa and are reported to have very high annual water requirements, this information is particular important for this valuable crop. This study therefore attempted to evaluate how water stress at different phenological stages (flowering and nut set, nut sizing, nut filling and shuck dehiscence) impacts pecan (Carya illinoinensis Wangenh. K.Koch) yield and quality. A trial was conducted in a 12-year-old pecan orchard at Innovation Africa @UP over three consecutive seasons. Measurements included several plant physiological responses to quantify the level of plant stress throughout the growing season and yield and quality measurements at the end of each season. Water stress (midday stem water potential <-0.9 MPa) led to a decline in stomatal conductance, photosynthesis, transpiration, and growth (especially during bud break). At the flowering and nut set stage, water stress led to significant flower abortion and nut fall, which reduced the final number of nuts by 60%, which ultimately reduced the final yield compared to well-water control. Water stress at nut growth stage, did not necessarily reduce the final yield at this stage, but rather reduced the nut size (many smaller nuts), thereby compromising the nut quality and income. Water stress at the nut filling stage significantly reduced both the yield and nut quality, reducing the nut mass, due to a high percentage of wafers/air pockets as a result of poor nut filling. Stress during the final phenological stage, shuck dehiscence, did not have a major impact on final yield or quality, but there was an increase in the number of stick-tights. However, over the three seasons the increase in the number of stick tights did not always translate into a significant reduction in yield when compared to the control. Therefore, in seasons where water allocations are reduced, it may be possible to make some water savings during nut sizing and shuck dehiscence without compromising yield. However, some reduction in quality and income may result if the trees are stressed during these stages. Water research commission, SAPPA and MasterCard foundation Plant Production and Soil Science MScAgric (Horticulture) Unrestricted 2022-02-10T09:09:10Z 2022-02-10T09:09:10Z 2022 2021 Dissertation * A2022 http://hdl.handle.net/2263/83752 en © 2022 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 | UCTD Horticulture Water stress Phenological stages The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title | The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title_full | The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title_fullStr | The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title_full_unstemmed | The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title_short | The impact of water stress at key phenological stages on yield and quality of pecans (Carya illinoinensis Wangenh. K.Koch) |
| title_sort | impact of water stress at key phenological stages on yield and quality of pecans carya illinoinensis wangenh k koch |
| topic | UCTD Horticulture Water stress Phenological stages |
| url | http://hdl.handle.net/2263/83752 |