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Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment
Thesis (MScAgric)--Stellenbosch University, 2021.
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| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614136803786752 |
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| access_status_str | Open Access |
| author | Lötter, Devan DeVilliers |
| author2 | Pieterse, P. J. |
| author_browse | Lötter, Devan DeVilliers Pieterse, P. J. |
| author_facet | Pieterse, P. J. Lötter, Devan DeVilliers |
| author_sort | Lötter, Devan DeVilliers |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/109987 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:47:15.075Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/109987 Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment Lötter, Devan DeVilliers Pieterse, P. J. Strauss, Johann A. Lombard, P. Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy. Canola -- Varieties Canola -- Seeds -- Quality Canola -- Seeds -- Viability Canola -- Seeds -- South Africa -- Western Cape Cultivars -- South Africa Crop -- Effect of drought on UCTD Thesis (MScAgric)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Laboratory, greenhouse and field trials were conducted in 2020 to compare the effectiveness of general seed quality parameters and certain seed vigour parameters to the actual field establishment success of several common canola (Brassica napus L.) cultivars from South Africa. Fourteen different, commonly cultivated, canola cultivars that were available on the South African retail seed market for the year 2020, were obtained from various seed marketing companies. For the sake of confidentiality in this study, the 14 cultivars were randomly assigned a code number from 1 to 14 and referred to by these code numbers. The general seed quality parameters determined in this study included germination percentage, thousand seed mass (TSM) and seed size fractioning. The germination percentages of the cultivars were determined by germinating seed as described by the International Seed Testing Association (ISTA). The TSM of all cultivars was determined by counting out 5 replications of 1000 seed from each cultivar and weighing each replication to determine the mean TSM. Seed size fractioning was done by dividing 3 replicates of each cultivar into three size classes and determining the mean percentage of each size class per cultivar. The size classes were classified as small (<1.7 mm), medium/normal (1.7-2.0 mm) and large (>2.0 mm). The vigour testing parameters used to test seed vigour of all the cultivars included germination and emergence after accelerated ageing (AA), planting depth emergence and drought stress emergence. Accelerated ageing (AA) was done by ageing seed for 0, 24, 48 and 72 hours in a temperature-controlled growth chamber at 42 °C ± 0.5 °C before germination and emergence testing. The planting depth emergence was determined by planting seeds from each cultivar at four different depths, 10 mm, 20 mm, 40 mm and 60 mm. The drought stress emergence was determined by determining emergence of each cultivar while watering was done by an 0.2% Polyethylene glycol 6000 (PEG-6000) solution with an osmotic potential of about -500 kPa, simulating 50% field water capacity. Six canola cultivar field trials were then planted across the production areas of the Western Cape of South Africa to collect field emergence, field establishment, biomass, leaf area index (LAI) and yield data to compare to general seed quality and seed vigour results. The main aim of the study was however to determine the effectiveness of general seed quality and seed vigour to determine potential field establishment. After regression analysis of several general seed quality, seed vigour and field trial results during this study it could be concluded that germination percentage had a moderate predicting ability on field emergence, but seed vigour parameters are best to predict potential field emergence and establishment. Although seed vigour gives a good indication of field establishment, there is no significant correlation with biomass, LAI and eventually yield. AFRIKAANSE OPSOMMING: Verskeie laboratorium-, glashuis- en veldproewe is in 2020 gedoen om die verhoudings tussen algemene saadkwaliteitparameters, sekere saadlewenskragtigheidparameters en die werklike veldvestiging sukses van verskeie algemene canola (Brassica napus L.) kultivars beskikbaar in Suid-Afrika te ondersoek. Veertien verskillende, algemeen beskikbare, canola-kultivars wat vir die jaar 2020 op die Suid-Afrikaanse saadmark beskikbaar was, is van verskillende saadbemarkingsmaatskappye verkry. Ter wille van vertroulikheid was al 14 kultivars lukraak 'n kodenommer van 1 tot 14 toegeken en in hierdie studie word slegs na hierdie kodenommers verwys. Die algemene saadkwaliteitparameters wat in hierdie studie bepaal is, het ontkiemingspersentasie, duisendkorrelmassa (DKM) en fraksionering van saadgrootte ingesluit. Die ontkiemingspersentasies van die kultivars is bepaal deur saad te ontkiem soos beskryf deur die ‘International Seed Testing Association’ (ISTA). Die DKM van alle kultivars is bepaal deur 5 herhalings van 1000 sade by elke kultivar uit te tel en dan elke herhaling te weeg om die gemiddelde DKM te bepaal. Saadgrootte-fraksionering is gedoen deur 3 herhalings (± 30 gram) van elke kultivar in drie grootteklasse te verdeel en die gemiddelde persentasies van elke grootte-klas per kultivar te bepaal. Die grootte klasse is geklassifiseer as klein (<1,7 mm), medium / normaal (1,7-2,0 mm) en groot (> 2,0 mm). Die lewenskragtigheidsparameters wat gebruik was om saadlewenskragtigheid van al die kultivars te toets, sluit in ontkieming en opkoms na versnelde veroudering (AA) asook vestigingspersentasies van plantdiepte- en droogtestremmingsproewe. Versnelde veroudering (AA) is gedoen deur saad vir 0, 24, 48 en 72 uur te verouder in 'n temperatuurbeheerde groeikamer teen ‘n konstante temperatuur van 42 ° C ± 0,5 ° C, voor ontkieming en opkoms toetse gedoen is. Die vestigingspersentasies van die plantdiepte proef is bepaal deur sade van elke kultivar op vier verskillende dieptes, 10 mm, 20 mm, 40 mm en 60 mm, te plant in ‘n potproef. Die vestigingspersentasies van die droogtestremmingsproef is bepaal deur die opkoms van elke kultivar te bepaal, terwyl watertoediening vervang is deur toedienings van 0,2% poliëtileenglikol 6000 (PEG-6000) oplossings met osmotiese potensiaal van ongeveer -500 kPa, wat 50% veldwaterkapasiteit simuleer. Ses canola kultivar veldproewe is daarna op vier verskillende plase regoor die produksiegebiede van die Wes-Kaap van Suid-Afrika geplant om veldopkoms, veldvestiging, biomassa, blaaroppervlakte-indeks (LAI) en opbrengsdata in te samel en te korreleer met die resultate van die algemene saadkwaliteit en saadlewenskragtigheidresultate. Die hoofdoel van die studie was egter om die doeltreffendheid van algemene saadkwaliteit en saadlewenskragtigheid te bepaal om potensiële vestiging in die veld te bepaal. Na regressie-analise van verskeie algemene saadkwaliteit-, saadlewenskragtigheid- en veldproefresultate tydens hierdie studie kon daar tot die gevolgtrekking gekom word dat ontkiemingspersentasie 'n matige voorspellingsvermoë van veldopkoms gehad het, maar saadlewenskragtigheidparameters oor die algemeen die beste is om potensiële veldopkoms en vestiging te voorspel. Alhoewel saadlewenskragtigheid 'n goeie aanduiding gee van veldvestiging, is daar egeter geen beduidende korrelasie met biomassa, LAI en uiteindelik opbrengs nie. Masters 2021-03-02T17:01:16Z 2021-04-21T14:35:09Z 2021-03-02T17:01:16Z 2021-04-21T14:35:09Z 2021-03 Thesis http://hdl.handle.net/10019.1/109987 en_ZA en_ZA Stellenbosch University xvi, 132 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Canola -- Varieties Canola -- Seeds -- Quality Canola -- Seeds -- Viability Canola -- Seeds -- South Africa -- Western Cape Cultivars -- South Africa Crop -- Effect of drought on UCTD Lötter, Devan DeVilliers Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title | Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title_full | Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title_fullStr | Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title_full_unstemmed | Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title_short | Seed viability versus seed vigour of canola (Brassica napus L.) cultivars in South Africa and the impact on establishment |
| title_sort | seed viability versus seed vigour of canola brassica napus l cultivars in south africa and the impact on establishment |
| topic | Canola -- Varieties Canola -- Seeds -- Quality Canola -- Seeds -- Viability Canola -- Seeds -- South Africa -- Western Cape Cultivars -- South Africa Crop -- Effect of drought on UCTD |
| url | http://hdl.handle.net/10019.1/109987 |
| work_keys_str_mv | AT lotterdevandevilliers seedviabilityversusseedvigourofcanolabrassicanapuslcultivarsinsouthafricaandtheimpactonestablishment |