Crop Science Masters Investigates Water Efficiency of Underutilised Crop

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Ms Tendai Chibarabada was awarded her Masters of Science degree in Agriculture (Crop Science) at a graduation ceremony in Pietermaritzburg with her thesis titled: Seed Quality and Water Use Characteristics of a Bambara Groundnut (Vigna subterranea L) Landrace Differing in Seed Coat Colour.

Her research focused on the bambara groundnut, an underutilised legume crop which is indigenous to Africa, having originated in Mali. The water-efficient crop is a useful food source and can be used in a variety of ways, from being a source of vegetable milk and flour to being used to produce a paste which is used to prepare akara - a traditional African food. Additionally, fermented bambara groundnut flour has high nutritional quality and is recommended for use in weaning food formulation.

Chibarabada’s study examined the seed quality of selected seed coat colours of bambara groundnut, and determined water use efficiency during seedling establishment as well as the effect of water stress on maternal plants and the subsequent seed quality of the bambara groundnut.

Her thesis also highlighted the fact that the bambara groundnut seed contained sufficient quantities of protein, carbohydrates and fat as well as appreciable amounts of micro nutrients, to meet nutritional recommendations set forward by the Food and Agriculture Organisation (FAO) of the United Nations and the World Health Organisation (WHO). Water from the boiled grain has also been used by the Luo tribe in Kenya to treat diarrhoea, indicating possible medicinal properties.

In addition to all of these benefits, the bambara groundnut does not need nitrogen fertiliser application, meaning that even resource-constrained households can participate in its production.

The crop, also known as jugo beans, izindlubu, round beans and nyimo in South Africa, is widely cultivated in Sub-Saharan Africa. According to Chibarabada, the bambara groundnut is the third most important legume after groundnut and cowpea, despite slowly being replaced by exotic species of groundnuts.

Chibarabada’s research was part of a Water Research Commission (WRC) project her supervisor, Dean and Head of the School of Agricultural, Earth and Environmental Sciences (SAEES), Professor Albert Modi is heading up.

Her research concluded that the colour of the seed coat has an effect on the seed quality, and that bambara groundnut seedlings improved water use efficiency under decreasing water supply. Despite the resilience of the crop, particularly in a water-scarce country like South Africa, the research also established that sub-optimum growing conditions (rainfed) resulted in progeny of inferior seed viability, suggesting that optimum conditions are needed for bambara groundnut seed production. In the absence of this, explained Chibarabada, farmers may risk recycling seed with inferior seed quality, which may negatively affect yields in the short to medium term.

Modi, who has supervised one PhD student and four Masters students working on this crop, commented on the excellence of Chibarabada’s work and commended her as a student.

‘Tendai completed her Masters in record time, finishing it within 12 months with two publications to boot,’ he said. ‘She also worked independently and wrote her work up very well.’

Chibarabada is pleased with the results of her study, which she hopes will contribute to the growing body of knowledge on an underutilised, resilient crop which has potential to contribute to reducing food insecurity. Her work has resulted in the publication of two articles, one with the South African Journal of Plant and Soil, based on the first chapter of her thesis, and a second one with the Acta Agriculturae Scandinavica journal in its Soil and Plant Science section. A third article is under review for publication.

She hopes the results of these kinds of studies will contribute to the realisation of the crop’s potential in terms of crop improvement, which would increase its yields and enable it to be a commercially-available, promoted seed crop.

Having studied for her undergraduate degree in Horticulture at the Africa University in Zimbabwe, Chibarabada chose to pursue her Honours and Masters degrees at UKZN because of the institution’s reputation being strong in agricultural disciplines.

She thanked Modi, and Crop Science researcher Dr Tafadzwanashe Mabhaudhi for their vital support during her studies.  

Chibarabada conducted her research at the University’s Ukulinga Research Farm as well as with rural communities in Swayimani.

‘I was very grateful for the opportunity to work with communities and in PR at UKZN, because that’s not a chance everybody gets and it contributed a lot to my work,’ said Chibarabada.

She plans to pursue her PhD at UKZN, also in water-related projects on underutilised crops.