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Detection of Fusarium spp. on maize kernels

Dissertation (MInstAgrar (Crop Protection))--University of Pretoria, 2012.

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Other Authors: Aveling, Terry A.S.
Format: Thesis
Language:English
Published: University of Pretoria 2013
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author2 Aveling, Terry A.S.
author_browse Aveling, Terry A.S.
author_facet Aveling, Terry A.S.
collection Thesis
dc_rights_str_mv © 2012, 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 (MInstAgrar (Crop Protection))--University of Pretoria, 2012.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:39:26.678Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
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publisher University of Pretoria
publisherStr University of Pretoria
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spelling oai:repository.up.ac.za:2263/31460 Detection of Fusarium spp. on maize kernels Aveling, Terry A.S. renaanthompson@yahoo.com Priesto, R. Blanco Thompson, Renaan Shane UCTD Fusarium species Fungal species Maize seeds Dissertation (MInstAgrar (Crop Protection))--University of Pretoria, 2012. In terms of amount of tonnes produced each year, Zea mays also known as maize and corn is the most important crop. Fungi cause significant destruction of maize in the field as well as during storage rendering the grain unsuitable for human consumption by decreasing its nutritional value and by producing mycotoxins that are detrimental to both human and animal health. Fusarium species are widely distributed and are amongst the most frequently isolated fungal species by plant pathologists and due to the fact that the Fusarium species involved in maize ear rot vary in fungicide sensitivity, pathogenicity as well as in their capability to produce mycotoxins, accurate quantification and identification is of paramount significance. There is currently no method developed for Fusarium detection in maize seed that has been validated by ISTA (the International Seed Testing Association). Malachite green agar 2.5 ppm (MGA 2.5) is a potent selective medium for isolation and enumeration of Fusarium spp. In this study, eight different media compositions, potato dextrose agar (PDA), PDA + malachite green oxalate, corn meal agar, ½ PDA + malachite green oxalate, 1% malt agar, carnation leaf agar supplemented with potassium chloride (KCLA), malachite green agar (MGA 2.5) and MGA 2.5 + sterile carnation leaf pieces (MGA 2.5 +) were compared using four Fusarium species (F. graminearum, F. proliferatum, F. subglutinans and F. verticillioides) and five commonly encountered saprophytic fungi (Aspergillus niger, Penicillium crustosum, P. digitatum, Trichoderma harzianum and Rhizopus stolonifer). The maize kernels were surface disinfected using three concentrations of sodium hypochlorite (0.5%, 1% and 1.5%) and for different time intervals (1min, 3min, 5min and 10min). The effect of black-blue light (365nm) on sporulation of the fungi was also investigated. 200 maize sees from two seed lots were surface disinfested and plated out on PDA, KCLA, MGA 2.5 and MGA 2.5 and incubated at 25oC for 7d under 12h black-blue light/12h darkness. PDA, ½ PDA, 1% malt agar and KCLA allowed profuse growth of the Fusarium species as well as saprophytes. Media that contained malachite green oxalate was most inhibitory to the radial colony growth of the saprophytes and the Fusarium species. Fusarium species growing on these media formed under-developed morphological structures, thereby obscuring accurate identification. MGA 2.5 supplemented with sterile carnation leaves was the most satisfactory medium in hindering saprophytic growth while allowing adequate sporulation of the Fusarium species to permit correct identification. The media also had a higher Fusarium verticillioides and less saprophytic fungal isolation frequency when compared to the other media tested. The location of Fusarium verticillioides within maize seed was also investigated and found to be only associated within the upper pedicel part of the kernel. Copyright Microbiology and Plant Pathology Restricted Natural and Agricultural Sciences 2013-09-09T12:17:03Z 2012-12-14 2013-09-09T12:17:03Z 2012-09-07 2012-12-14 2012-11-30 Dissertation Thompson, RS 2012, Detection of Fusarium spp. on maize kernels, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11302012-140544 / > E12/9/124/gm http://hdl.handle.net/2263/31460 http://upetd.up.ac.za/thesis/available/etd-11302012-140544/ en © 2012, 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
Fusarium species
Fungal species
Maize seeds
Detection of Fusarium spp. on maize kernels
title Detection of Fusarium spp. on maize kernels
title_full Detection of Fusarium spp. on maize kernels
title_fullStr Detection of Fusarium spp. on maize kernels
title_full_unstemmed Detection of Fusarium spp. on maize kernels
title_short Detection of Fusarium spp. on maize kernels
title_sort detection of fusarium spp on maize kernels
topic UCTD
Fusarium species
Fungal species
Maize seeds
url http://hdl.handle.net/2263/31460
http://upetd.up.ac.za/thesis/available/etd-11302012-140544/