College of Agriculture, Engineering
and Science (CAES)

“Superfood” Sweet Potato has Enhanced Nutritional Value

Ms Sonia Naidoo can now add the title of doctor to her name after completing a PhD in Plant Breeding in which she bred new sweet potato varieties with enhanced nutritional value she hopes will contribute to fighting poverty, malnutrition and food insecurity.

A professional development student at the Agricultural Research Council’s Vegetable and Ornamental Plants (ARC-VOP), Dr Naidoo’s research was supervised by the ARC’s Dr Sunette Laurie and co-supervised by Professor Hussein Shimelis and Professor Mark Laing at UKZN’s African Centre for Crop Improvement.

A graduate of the University Eduardo Mondlane in Mozambique, Naidoo worked with sweet potatoes during her master’s degree and was fascinated by the vegetable, which is a staple food for both privileged and underprivileged communities.

‘Sweet potato is a superfood,’ said Naidoo. ‘It is one of the food security crop choices and it can make a difference in the livelihoods of underprivileged communities as a source of nutrients, caloric energy and fibre.’

Naidoo set out to help close what she perceived to be a gap in the knowledge about the crop’s nutritional values. The hardy crop’s short growing period of five to six months made it ideal for a PhD study.

Naidoo’s research included a novel investigation of the genetic diversity of protein content in sweet potato root among the South African germplasm collection, and – with a team involved in this study –  she was able to develop a Near Infra-Red Spectroscopy model for quantifying sweet potato protein, revealing the diversity and range of protein content in the South African collection.

Her research was not without its challenges – a severe storm in January 2018 almost destroyed her quarter of a hectare experimental site at the ARC-VOP research station in Roodeplaat.

A mother of two, she juggled raising her children and completing her studies. Passionate about the advancement of women in the sciences, Naidoo encouraged those engaged in science and research to press forward despite challenges, and to seize opportunities presented to them to advance their careers.

She said great women in her life – particularly her grandmother, mother and aunt – taught her to value education.  Her grandmother, a smallholder farmer, cultivated a love for plants in Naidoo who saw how the elderly woman managed to put food on the table for their whole family off her small plot of land.

Naidoo, who said her mother and aunt had supported and encouraged her to pursue her dream of acquiring Higher Education, thanked her children for their support as she often had to travel to other provinces to plant and harvest crop trials.

Through this research, Naidoo hopes that the importance of sweet potato as a strong contributor to the alleviation of poverty, malnutrition and food insecurity can be better appreciated, and that information uncovered on the diversity and the range of protein content on the South African sweet potato germplasm collection will be well used for future breeding of improved nutritious cultivars, and attract stronger research funding support from the private sector.

Despite the uncertainty and slow-down caused by COVID-19, Naidoo hopes to progress to a career in research and development or to postdoctoral research, and looks forward to applying the knowledge and skills she has gained for the betterment of society.

Naidoo thanked the ARC and the National Research Foundation for funding her research, and also Laurie, Shimelis and Laing for their guidance and support, especially Laurie for the professional mentorship she provided.

Words: Christine Cuénod

Photograph: Supplied