Horticultural Sciences
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First Lady of fruit retires

Prof Karin Theron, since 2014 the Hortgro Research Chair in Applied Pre-harvest Decidious Fruit Research in the Department of Horticultural Science, has retired after 36 years of service to Stellenbosch University. As emeritus professor she will still serve as lecturer and support postgraduate students.

In the industry she is often informally – and with the greatest respect – referred to as the “first lady of fruit”. This title does not only reflect the high regard in which she is held for her outstanding, practical research in support of the South African deciduous fruit industry and the fynbos flower sector, or the effort she has made to provide advice to producers and nursery owners.

As a student in the 1970s, she was literally the first woman who took Horticulture as a subject at SU. Prof Theron completed her BScAgric degree in 1980. Thereafter she also became the first woman to complete a master’s degree (in 1984, cum laude) and a PhD (1993) in this discipline.

She has been a torchbearer for women in science at SU, as the first woman to be appointed as lecturer in Horticultural Science (1985), the first associate professor (1996) and professor (2002). She was also the first to chair the SU Department of Horticultural Science (for two stints) and lead the SU Faculty of Agrisciences (between 2007 and 2008, as acting dean).

At a farewell function attended by current and former colleagues, Prof Theron was thanked for her tremendous contribution to the work done in the Department of Horticultural Sciences. Her leadership, compassion, friendship to many, thoroughness and love for coffee and nature hikes were highlighted.

Chair Dr Esme Louw said that Prof Theron has had a major impact on the direction and functioning of the Department. She highlighted how Prof Theron is the type of person who gives more than what is expected of her.

“As a great philosopher once said: a true leader is someone who knows the way, has walked the way and can show the way.”

At her core a lecturer
For Prof Theron there is almost nothing as fulfilling as being busy with practical orchard-based trials or being able to “read” a fruit tree and understand what is needed to get the best possible production from it. This is only topped by the opportunity to teach her undergraduate and postgraduate students how to do it themselves.

As lecturer she has developed core modules on deciduous fruit production. For years she was the one who gave Matie students following Horticultural Science 314 their first introduction to the industry and explained the basics behind the development and biology of deciduous fruit trees.

Prof Theron regards her influence on many young people – many of whom have gone on to make their mark in the agricultural sector – as her greatest achievement.

“Once all the students whom I currently still supervise graduate, I will have neatly guided the studies of around 100 postgraduate students,” she mentions with pride.

Back in the days, when she was freshly out of school after having matriculated from Bloemhof Girls’ High School in Stellenbosch, she had her sights set on becoming a landscape architect because of her love for plants and gardening. She still remembers how her father, Prof. Attie Theron, was chair of the Department of Soil Science at the time and advised her to first get an agricultural degree under the belt.

“Somewhere in my second year I started thinking that it is actually an interesting course,” she reminisces.

Over the years she done an orchard full of work on apples. It was a fruit that she started off working on half reluctantly as part of her master’s degree (about apical dominance among apple nursery trees). It would also become the topic for the first of her 70-odd peer reviewed research papers, in 1987, with two other legends in horticultural science, Prof Gerhard Jacobs and Prof Daan Strydom as co-authors.

“I received a government bursary for part of my BScAgric, and therefore had to go and work at a state institution. My first choice was to work at the then Protea Research Station at Riviersonderend, but I was seconded to Stellenbosch, to work at the then Fruit and Fruit Technology Research Institute,” she remembers her first hesitant steps in the deciduous fruit industry.

In the process, however, she realised “that all plants are actually interesting”, and that it is actually irrelevant which type one is studying if you love plants.

She could at least return to her first love – flowers – when she did her PhD research. Prof Theron looked at the growth and development of Nerine bowdenii, a popular indigenous bulb species with a pink flower, under supervision of Prof Jacobs. She would later co-author a chapter in a book about growing Amaryllidacea, and along with her students do research about proteas as cut flowers.

Through among others the Hortgro Research Chair, to which she was appointed in 2014, she has conducted many trials on pears, apples and stonefruit such as plums, nectarines and peaches. These have included studies on the use of growth regulators, as well as alternative chemical and mechanical methods to thin stone fruit and pome fruit, the pros and cons involved in using mechanisation options in the local deciduous fruit industry. These include harvesting systems, thinning machinery and platforms on which workers can stand while working.

Since her master’s degree days, she has been interested in improving nursery standards. Together with her students she has shown that better quality fruit trees suffering fewer diseases can be produced if these are raised in bags or containers rather than in open soil.

“I’ve quite recently helped Hortgo to write guidelines on the handling of nursery trees,” says this member of the Deciduous Fruit Plant Improvement Association.

With Prof Theron as their guide, numerous students have completed trials that ultimately led (or will still) lead to the registration of new plant growth regulators to be used among others for fruit thinning, improving fruit set, reducing shoot growth and colour improvement. These aspects all contribute to more profitable, quality orchards.

Over the years, fruit has taken the professor all over the world. Her insights and knowledge are sought after by the local and international fruit industry, and she has presented at workshops, producers’ days, symposiums and congresses around the world. She is a member of the International, American and South African societies for horticulturalists, and a member of the EUFRIN work group on fruit thinning. She serves as director on the board of Citrus Research International and ASNAPP and is a board member of the South African Society of Horticultural Science. She was also a member of the international science advisory committee of the 2014 International Horticulture Congress in Australia, and over the years organised international congresses about pear production and planting systems held in Stellenbosch.

“I’ve always seen myself as some sort of link between academia and the industry,” Prof Theron explains her reasoning for doing so much practical, industry focused research. “It is an important partnership.”

Although she is officially retiring, she will still be making her mark in the fruit sector. As consultant she will do trials for the agrichemical company Philagro, help with technology transfer and mentoring newly appointed staff. She will continue helping Hortgro Science to evaluate research projects, to serve on working groups and to help with drafting guidelines on best practices for orchard management and nurseries.

For the foreseeable future she will also still present Horticulture 314. This regular keynote speaker, who has presented at international congresses from Chili, Brazil and Uruguay to Australia and Portugal has some more travelling in her sights. She has already been invited to be a keynote speaker at the 31st International Horticultural Science Congress in France next year.

She also kicked off her so-called retirement with some great news, as she was recently named the Western Cape’s top agriculturalist for 2021 by the Agricultural Writers of South Africa.