UKZN Academic Gets Award for Best Paper Published in Plant and Soil Journal

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Professor Hussein Shimelis of the African Centre for Crop Improvement (ACCI) in the School of Agricultural, Earth and Environmental Sciences (SAEES) has received the award for the best paper published in the SA Journal of Plant and Soil by a member of the South African Society of Crop Production (SACP).

The award was made during the annual Combined Congress of SACP, the Soil Science Society of South Africa, the Southern African Society for Horticultural Sciences and the Southern African Weed Science Society.

The Congress, with the theme: “Taking Research to the Farm to Ensure Long-Term Sustainability”, was held in George towards the end of last month.

The paper submitted by Shimelis, which deals with a seed oil crop called vernonia (Centrapalus pauciflorus), is unique in its use of statistical methodology to identify principal agronomic and seed oil traits in the East African plant.

Known as a weed in the countries where it occurs naturally, the plant was initially identified in a study in the United States as having the potential to act as a more environmentally-friendly, cost-effective source of seed oil for industrial uses.

Vernonia, which is found in countries such as Kenya, Ethiopia and Tanzania, is a source for naturally epoxidised seed oil. This means that the oil extracted from the seeds does not have to undergo epoxidation, an expensive chemical process necessary to make other seed oils useable, which utilises noxious petro-chemical substances in the manufacturing process and pollutes the environment with harmful volatile compounds.

The naturally epoxidised oil extracted from the vernonia, however, has the potential to revolutionise the industrial oil and plastics industries as well as be used in the paint industry and in epoxy resins where it could prevent the substances from releasing volatile compounds into the air. Additionally, the seedcakes remaining after the extraction process could be used in animal feed, with experiments in that application underway.

Shimelis, whose study approaches the crop from a Plant Breeding perspective, set out to characterise the 36 genotypes of the plant and evaluate which influential and representative characters of the genotypes would be useful for breeding in the high oil yielding varieties.  Some of the varietal selections determined that some strains of vernonia could yield up to 900 litres of oil per hectare.

Breeding of the plant aims to combine high seed-yielding varieties that don’t have high oil yields, with varieties which are higher in oil content. There is potential for more research, as it is necessary to examine how vernonia fares in frost-free and more suitable agro-physical environments in South Africa.

To do this characterisation of the selections, Shimelis and his co-authors conducted field evaluations and fatty acid analyses. Professor Phatu Mashela of the University of Limpopo piloted the field evaluations using agronomic traits and Professor Arno Hugo of the University of the Free State undertook the oil and fatty acid analyses. The three co-authors utilised the Principal Component Analysis (PCA) as a statistical method to identify the most influential and representative characteristics of the diverse genotypes to try and ensure effective breeding for a plant with so much potential.

What makes this study unique, according to Shimelis, is the fact that PCA methodology will be applicable to other crops in plant breeding programmes for germplasm evaluation and selection. Additionally, Shimelis says the level of presentation is accessible to students and researchers, even if they are not statisticians or have limited backgrounds in statistics.

The paper also contained well-illustrated findings and interpreted PCA as a statistical methodology. With relatively little emphasis on the PCA methodology itself and limited use of statistical jargon, the researchers demonstrated the direct application of PCA for selection and grouping of germplasm collections. The direct impact of the use of this method for genetic resource characterisation of other crops has already been demonstrated by two of Shimelis’s PhD students, who have used the methodology in research related to breeding of sorghum (the results of which were published in the American Journal of Crop Science) and sweet potato (published in the Journal of Tropical Agriculture).

According to Shimelis, the use of PCA led to novel insights in selections of vernonia lines that go beyond what can be expected from a routine germplasm characterisation, which has implications for methods of characterising important traits of plants for breeding to ensure germplasm conservation, food security, environmental sustainability and more.

Shimelis, who was accompanied to the Congress by four of the students he is supervising from various institutions, said such recognition of his research was a motivation to continue the work and achieve even more.

Christine Cuénod