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08 October 2020 | Story Leonie Bolleurs | Photo Supplied
Dr Cornel Bender
Dr Cornel Bender received her PhD qualification at the virtual graduation ceremonies in October. The title of her thesis is: Stem rust resistance in South African wheat and triticale.

The rapid distribution of disease-causing organisms such as Ug99, a wheat stem-rust pathotype, pointed out just how vulnerable global cereal production is to disease outbreaks.

These cereals include wheat, barley, rye, oats, triticale, rice, maize, and millet and are one of the most important food sources for human consumption.

According to Dr Cornel Bender, the projected world population of 10 billion in 2057 requires a growth of more than 40% in cereal production. Wheat is grown on more hectares than any other cereal and is one of the most important sources of calories for humans. However, the growth rate of wheat yields has declined from the 1960s to the 1990s. Therefore, it is essential to increase global wheat production.

“With the regular appearance of more aggressive stem rust pathotypes in South Africa, there is a constant need to discover new sources of resistance, understand the genetic base of presently deployed sources in wheat, triticale and barley cultivars, and to manipulate the deployment of resistant sources through a more sustainable approach,” says Dr Bender.

Her PhD thesis, titled: Stem rust resistance in South African wheat and triticale, includes various fundamental aspects for the effective management of stem rust in South Africa.

Dr Bender is a Professional Officer in the Division of Plant Pathology in the Department of Plant Sciences, who received her PhD at the virtual graduation ceremonies in October.

Innovative and cost effective

Her promotors, Prof Zakkie Pretorius, Research Fellow, and Dr Willem Boshoff, Senior Lecturer in the Department of Plant Sciences, believe that she used an innovative approach to develop a cost-effective phenotyping method to select for more durable resistance types in a controlled greenhouse environment.

“In the past, results obtained from field trials used to assess adult plants for stem-rust resistance, were often influenced by abiotic factors, were seasonable in nature, expensive, and time consuming; therefore, the development of a dependable greenhouse screening system provides an important additional instrument for rust research,” says Dr Bender.

She adds that the greenhouse technique is used worldwide to screen for adult plant resistance and contribute to save time and money.

Broadening our knowledge

“Inheritance studies were undertaken to determine the genetic base of stem-rust resistance in selected South African wheat and triticale cultivars (developed from wheat/rye crosses) through seedling analysis as well as greenhouse and fieldwork,” she says.

Dr Bender believes the use and development of different resistance screening methods, the elucidation of host genetics, as well as the use of histological and microscopic methods to study early resistance responses, broaden our knowledge and understanding of stem-rust resistance in South African wheat and triticale cultivars.

Ultimately, rust researchers, grain producers, and also the general public – through access to their daily bread – will benefit from her study.

News Archive

NRF grants of millions for Kovsie professors
2013-05-20

 

Prof Martin Ntwaeaborwa (left) and Prof Bennie Viljoen
20 May 2013


Two professors received research grants from the National Research Foundation (NRF). The money will be used for the purchase of equipment to add more value to their research and take the university further in specific research fields.

Prof Martin Ntwaeaborwa from the Department of Physics has received a R10 million award, following a successful application to the National Nanotechnology Equipment Programme (NNEP) of the NRF for a high-resolution field emission scanning electron microscope (SEM) with integrated cathodoluminescence (CL) and energy dispersive X-ray spectrometers (EDS).

Prof Bennie Viljoen from the Department of Microbial, Biochemical and Food Biotechnology has also been awarded R1,171 million, following a successful application to the Research Infrastructure Support Programme (RISP) for the purchase of a LECO CHN628 Series Elemental Analyser with a Sulphur add-on module.

Prof Ntwaeaborwa says the SEM-CL-EDS’ state-of-the art equipment combines three different techniques in one and it is capable of analysing a variety of materials ranging from bulk to individual nanoparticles. This combination is the first of its kind in Africa. This equipment is specifically designed for nanotechnology and can analyse particles as small as 5nm in diameter, a scale which the old tungsten SEM at the Centre of Microscopy cannot achieve.

The equipment will be used to simultaneously analyse the shapes and sizes of submicron particles, chemical composition and cathodoluminescence properties of materials. The SEM-CL-EDS is a multi-user facility and it will be used for multi- and interdisciplinary research involving physics, chemistry, materials science, life sciences and geological sciences. It will be housed at the Centre of Microscopy.
“I have no doubt that this equipment is going to give our university a great leap forward in research in the fields of electron microscopy and cathodoluminescence,” Prof Ntwaeaborwa said.

Prof Viljoen says the analyser is used to determine nitrogen, carbon/nitrogen, and carbon/hydrogen/nitrogen in organic matrices. The instrument utilises a combustion technique and provides a result within 4,5 minutes for all the elements being determined. In addition to the above, the machine also offers a sulphur add-on module which provides sulphur analysis for any element combination. The CHN 628 S module is specifically designed to determine the sulphur content in a wide variety of organic materials such as coal and fuel oils, as well as some inorganic materials such as soil, cement and limestone.

The necessity of environmental protection has stimulated the development of various methods, allowing the determination of different pollutants in the natural environment, including methods for determining inorganic nitrogen ions, carbon and sulphur. Many of the methods used so far have proven insufficiently sensitive, selective or inaccurate. The availability of the LECO analyser in a research programme on environmental pollution/ food security will facilitate accurate and rapid quantification of these elements. Ions in water, waste water, air, food products and other complex matrix samples have become a major problem and studies are showing that these pollutants are likely to cause severe declines in native plant communities and eventually food security.

“With the addition of the analyser, we will be able to identify these polluted areas, including air, water and land pollution, in an attempt to enhance food security,” Viljoen said. “Excess levels of nitrogen and phosphorous wreaking havoc on human health and food security, will be investigated.”

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