Dr. Chrisna Steyn is a lecturer in Plant Breeding whose work focuses on improving legumes through the integration of plant pathology and molecular breeding. Her research is driven by a passion for developing disease-resistant cultivars that can withstand challenging production conditions while maintaining strong yield potential and quality traits. Through her work, she contributes to the advancement of sustainable agriculture and the development of innovative South African crop cultivars for future food security. 

Bachelors in Agricultural Science (BSc. Agric) 
University of the Free State
MAJOR SUBJECTS: Plant Pathology and Entomology

Magister in Agricultural Science (MSc. Agric) 
University of the Free State
MAJOR SUBJECT: Plant Pathology
Title: Study of inoculation and disease evaluation techniques for sclerotinia stalk rot (Sclerotinia sclerotiorum) of soybean

Philosophiae Doctor (PhD) 
University of the Free State
MAJOR SUBJECT: Plant Pathology
Title: Soybean response to rust and sclerotinia stem rot under different biotic and abiotic conditions

Cultivar screening for resistance characteristics.
Identifying races and determine genetic relationship among and within species.
Investigating the role of oxalic acid in S. sclerotiorum pathogenicity.
Investigation and evaluation of physiological mechanisms of soybean resistance to P. pachyrhizi
Effect of planting date, weather conditions and onset interactions on disease development.
Testing the effect of induced resistance on soybean rust and sclerotinia disease development.

CONFERENCE CONTRIBUTIONS
Botha, C. & McLaren, N.W. 2007. Evaluation of the inoculation techniques for Sclerotinia sclerotiorum on soybeans. Paper presented at the 45th Congress of the Southern African Society for Plant Pathology (SASPP), Benoni, South Africa. 21-24 January. (Oral presentation)

Botha, C., McLaren, N.W., & Swart, W.J. 2009. Epidemiology of Sclerotinia stem rot in South Africa. 46th Congress of the Southern African Society for Plant Pathology and 6th Congress of the African Mycological Association (AMA), Gordon’s Bay, South Africa, 25-28 January. (Oral presentation)

Labuschagne, M.T., Moloi, J., Steyn, C. & van Biljon, A. 2013. The effect of heat, drought, and cold stress on protein composition on and some quality and Mixsmart characteristics in wheat. International Wheat Genetics Symposium. Yokohama, Japan, 8-14 September 2013 (Poster).

Steyn, C., McLaren, N.W., Flett, B. & Minnaar-Ontong, A. 2013. Genetic variation of Sclerotinia sclerotiorum isolates in South Africa. 15th International Sclerotinia Workshop, Wuhan, China, 20- 24 August 2013 (Oral presentation).

Steyn, C., McLaren, N.W., Flett, B.C. & Minnaar-Ontong, A. 2013. Genetic variation of Sclerotinia sclerotiorum isolates in South Africa and resistance in soybeans. 23rd Soil Borne Diseases Interest Group, Stellenbosch, September 2013 (Oral presentation).

Steyn, C., McLaren, N.W., Flett, B. and Minnaar-Ontong, A. 2014. Preliminary population genetic study of Sclerotinia sclerotiorum in South Africa. Poster at the 10th Southern African Plant Breeding Symposium, March 2014, The Maria Moroka Nature Reserve, Black Mountain Leisure, and Conference Hotel, Thaba ‘Nchu. (Poster)

Rothmann, L.A., Steyn, C. & McLaren, N.W. 2017. Epidemiology of Sclerotinia stem rot of soybean: A South African perspective. Poster presented at the 15th National Sclerotinia Initiative, Minneapolis, Minnesota, USA, 18-20 January. (Poster)

McLaren, N.W., Rothmann, L.A., Bester, M.C. & Steyn, C. 2018. Sclerotinia stem rot of soybean: the South African approach. Poster presented at the 11th International Congress of Plant Pathology: Plant Health in a Global Economy, Heyns Convention Centre, Boston, USA. 29 July-3August. (Poster)

Meyer, C., Steyn, C. & Minnaar-Ontong, A. 2018. Population genetic structure of Sclerotinia sclerotiorum in South Africa. Paper delivered at the Soilborne Plant Diseases Symposium Agricultural Research Council, Stellenbosch, South Africa. 17-19 September. (Oral presentation)

Meyer, C., Steyn, C. & Minnaar-Ontong, A. 2018. South Africa’s big bang pathogen: Sclerotinia Sclerotiorum. Paper delivered at the 12th Southern African Plant Breeding Symposium, Gateway Hotel, Durban, South Africa. 12-14 March. (Oral Presentation)

Tóth, B., Moloi, M.J., Steyn, C., van Biljon, A. & Labuschagne, M. 2018. The effect of low nitrogen and low phosphorous and a combination of the two on the quantity of HMW-GS in two South African bread wheat cultivars. Paper delivered at the 13th International Gluten Workshop, Hilton, Mexico City. 14-17 March. (Oral Presentation)

Tóth, B., Moloi, M.J., Steyn, C., van Biljon, A. & Labuschagne, M. 2018. The influence of nitrogen and phosphorous deficiency on protein quality and quantity in two bread wheat cultivars in South Africa. Paper delivered at the 4th Latin American Cereals Conference, Hilton, Mexico City. 11-14 March (Oral Presentation)

Rothmann, L.A., Bester, M.C., Steyn, C. & McLaren, N.W. 2019. A community of practice: modelled on Sclerotinia stem rot of soybean. Paper delivered at the 51st Congress of the Southern African Society for Plant Pathology, Club Mykonos, Langebaan. 20-24 January. (Oral Presentation)

Tóth, B., Moloi, J., van Biljon, A., Steyn, C. & Labuschagne, M. 2019. The effect of fertilization level on the quantity of high molecular weight glutenin subunits in two South African spring wheat cultivars. In: Proceedings of the 13th International Gluten Workshop. Mexico City, Mexico, 14-17 March. Guzman, C. (ed.). University of Cordoba Press pp81-83.

Steyn, C., McLaren, N.W., Flett, B. and Minnaar-Ontong, A. 2013.  Genetic variation of Sclerotinia sclerotiorum isolates in South Africa.  15th International Sclerotinia Workshop: August 2013, Wuhan, China. (Oral Presentation)

Steyn, C., McLaren, N.W., Flett, B. and Minnaar-Ontong, A. 2013. Genetic variation of Sclerotinia sclerotiorum isolates in South Africa and resistance of soybean (Oral Presentation). Soilborne Plant Diseases Symposium: September 2013, ARC, Stellenbosch.

Grain SA research workshop, Grain SA, Pretoria, South Africa. Steyn, C. and Minnaar-Ontong, A. 2021. Sclerotinia Sclerotiorum Population dynamics: A South African perspective (Oral Presentation).   Grain SA research workshop, Grain SA, Pretoria, South Africa.

Steyn, C. and Minnaar-Ontong, A. 2022. Improvement of South African soybean cultivars against Sclerotinia stem rot (Oral Presentation).   National Grain Research Programme Research Day, Pretoria, South Africa. 10 May.

Steyn, C. Meyer, C. Minnaar-Ontong, A.  Characterization of the Sclerotinia sclerotiorum population on soybean and sunflower in South Africa to improve resistance breeding strategies. 2023. (Oral Presentation). EUCARPIA International congress on Oil & Protein Crops. November 2023. Antalya, Turkey

M.P.A. Coetzee, L. Matodzi, A. Minnaar-Ontong, C. Steyn, N. Yilmaz and C.M. Visagie.  Fusarium species causing (or associated with) Sudden Death Syndrome like symptoms on soybean in South Africa Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa Department of Plant Sciences, Plant Breeding, University of the Free State, Bloemfontein, South Africa.  South African Society of Plant Pathology, 2024.  

Minnaar-Ontong, A & Steyn, C.  Evaluation of Essential Oils as Potential Bio-Fungicides Against Soybean Sudden Death Syndrome in South African Soybean Cultivars.  (Oral presentation).  12th International Conference on Agriculture – AGRICO 2025. 22nd–23rd September 2025. Bangkok, Thailand

Steyn, C, Rikhotso, E, & Minnaar-Ontong, A.  Greenhouse screening for Sclerotinia stem rot resistance in soybean: Evaluation of inoculation methods, pathogen isolates and genotypic response. (Oral Presentation). 12th International Conference on Agriculture – AGRICO 2025. 22nd–23rd September 2025. Bangkok, Thailand

Botma, W, Minnaar-Ontong, A, Henning, JS, R.van der Merwe, M. Bairu, & Steyn, C. Genetic Diversity Analysis of 276 Cowpea (Vigna unguiculata L. walp) Accessions Using SSR Markers.  (Oral presentation). 12th International Conference on Agriculture – AGRICO 2025. 22nd–23rd September 2025. Bangkok, Thailand

Steyn, C, Rikhotso, E, & Minnaar-Ontong, A.  Screening Soybean for Sclerotinia Stem Rot Resistance: Effects of Method, Isolate, and Genotype.   National Grain Research Programme Research Day, Pretoria, South Africa. March 2026.

Steyn, C, Rikhotso, E, & Minnaar-Ontong, A. Assessing soybean resistance to Sclerotinia stem rot under greenhouse conditions: Effects of inoculation methods, pathogen isolates, and genotype. (Poster presentation).  South African Plant Breeding Association symposium.  March 2026.

PUBLICATIONS
Botha, C., McLaren, N.W. & Swart, W.J. 2009. Evaluation of greenhouse inoculation techniques used to screen for Sclerotinia stem rot resistance in soybeans. South African Journal of Plant and Soil 26(1): 48-50.   10.1080/02571862.2009.10639932

Steyn, C., Mclaren, N.W. & Swart, W.J. 2011. The effect of temperature and period of high humidity on the development of Sclerotinia stem rot on soybeans in the greenhouse. South African Journal of Plant and Soil 28(3): 208-211.

Abdi, N., Van Biljon, A., Steyn, C. & Labuschagne, M.T. 2021. Bread Wheat (Triticum aestivum) Responses to Arbuscular Mycorrhizae Inoculation under Drought Stress Conditions. Plants 10(9), 1756; https://doi.org/10.3390/plants10091756

Neila Abdi, Angeline Van Biljon, Chrisna Steyn, and Maryke Tine Labuschagne. 2022. Salicylic Acid Improves Growth and Physiological Attributes and Salt Tolerance Differentially in Two Bread Wheat Cultivars.  Plants 11(14), 1853; https://doi.org/10.3390/plants11141853

Naila Abdi, Angeline Van Biljon, Chrisna Steyn, Maryke Labuschagne: 2023. Zn fertilizer and mycorrhizal inoculation effect on bread wheat cultivars grown under drought stress.  Life 2023, 13(5), 1078; https://doi.org/10.3390/life13051078

Abdi, N., Van Biljon, A., Steyn, C., & Labuschagne, M. (2024). Arbuscular mycorrhizal fungi impact on yield attributes, protein quantity and quality in bread wheat (Triticum aestivum L.) grown under drought stress. Arid Land Research and Management, 1–15. https://doi.org/10.1080/15324982.2024.2331125


POPULAR ARTICLES
Neal McLaren en Chrisna Botha. 2011. Is weerstand teen Sclerotinia stamvrot by sojabone moontlik.  SA Grain magazine.

Chrisna Steyn.  2019. Soya bean rust and Sclerotinia stem rot in the spotlight.  Oilseeds Focus Magazine.

Steyn, C. and Minnaar-Ontong, A. 2019. Sclerotinia population dynamics: A force to be reckoned with. Oilseed Focus Magazine

Steyn, C. and Minnaar-Ontong, A. 2022. Sclerotinia sclerotiorum: Light at the end of the tunnel? SA Grain Magazine

Mngomezulu, D., Rothman, L, Minnaar-Ontong, A & Steyn, C. 2025. Understanding FHB resistance: linking mycotoxins to disease management in wheat.  SA Grain Magazine.