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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

Discovery in Scorpius constellation may signify clean energy for Earth
2017-01-23

 Description: Discovery in Scorpius constellation may signify clean energy for Earth Tags: Discovery in Scorpius constellation may signify clean energy for Earth

Earlier this year, a group of international astronomers
announced the discovery of an exotic binary star system,
AR Scorpii. The system is in the Scorpius constellation.
Photos: Supplied

See article on Nature’s website 

In future, stargazers and astronomers will look at the Scorpius constellation near the Milky Way with new eyes. Earlier this year, a group of international astronomers announced the discovery of an exotic binary star system, AR Scorpii. The system is in the Scorpius constellation.

Prof Pieter Meintjes, researcher in the Department of Physics at the University of the Free State (UFS), worked with four colleagues on what he describes as a “wonderful discovery”. This sensational discovery, which could lead to the production of cleaner energy on Earth, will be published in the research journal, Nature, early in 2017.

Model developed to interpret new set of measurements
The exotic binary star which was discovered consists of a red dwarf and a white dwarf revolving around each other every 3,5 hours. The binary system showed very prominent pulsations of 117 and 118 seconds respectively. The pulsations can be explained by a bundle radiation produced by the white dwarf star.

“These new observations have shown that the radiation is strongly polarised, a sign that we are dealing with synchrotron radiation here. Synchrotron radiation is produced by electrons accelerated to extremely high energy levels in the magnetic field of the white dwarf star,” says Prof Meintjes.

He developed a theoretical model to interpret a new set of measurements that was taken by the 1,9 m telescope and the 10 m SALT telescope at the South African Astronomical Observatory (SAA0).

Totally unique phenomenon could contribute to energy production on Earth
“I further indicated that the interaction between the magnetic fields of the white dwarf star and the red dwarf star induces secondary processes that specifically describe the behaviour of the radiation in the radio band and infrared band accurately. AR Sco is the first white-red dwarf binary system of which all the pulsated radiation could be explained by the synchrotron process, which is totally unique,” says Prof Meintjes.

According to Prof Meintjes, the value of the model lies in the fact that the processes which produce the radiation in AR Sco, can also be applied to produce energy on Earth.

 

Plasma reactors are based on roughly the same processes which apply in AR Sco, and with refining, it could be utilised to generate electricity in future. This will be much cleaner than nuclear energy.

 

The model developed by Prof Meintjes explains all the radiation in the system – from radio waves to X-rays – in terms of electrons accelerated to extremely high energy levels by electric fields in the system, which then produce synchrotron radiation over a very wide band of the electromagnetic spectrum.

Prof Meintjes is currently working on a follow-up article examining the evolution of the AR Sco, in other words, the origin of such a unique system and the final state towards which it is evolving. “My vision for the immediate future is therefore to develop a model for the evolution of the source concerned,” he says.

 

 

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