Dr Stephen Harper
Principal Research Fellow
School of Agriculture and Food Sustainability
Book Chapter
Cheah, Zhong Xiang, O’Hare, Tim, Harper, Stephen and Bell, Michael (2024). Genetic and Agronomic Biofortification of Zinc in Maize and Sweetcorn (Zea mays L.). Phytoremediation and Biofortification: Strategies for Sustainable Environmental and Health Management. (pp. 201-223) New York, NY United States: Apple Academic Press. doi: 10.1201/9781003402084-10
Journal Articles
Hong, Hung Trieu, Agarwal, Rimjhim, Takagi, Tatsuyoshi, Netzel, Michael E., Harper, Stephen M. and O'Hare, Tim J. (2025). A modified extraction and saponification method for the determination of carotenoids in the fruit of Capsicum annuum. Agriculture, 15 (6) 646, 646-6. doi: 10.3390/agriculture15060646
Nguyen, Binh Thi, Wehr, Johannes Bernhard, Kopittke, Peter Martin, O’Hare, Timothy James, Menzies, Neal William, Hong, Hung Trieu, McKenna, Brigid Ann, Klysubun, Wantana and Harper, Stephen Mark (2024). Benchmarking bulb yield, medicinal sulfur compounds, and mineral nutrition of garlic varieties. ACS Omega, 9 (45), 45240-45250. doi: 10.1021/acsomega.4c06678
Nurulita, Sari, Geering, Andrew D. W., Crew, Kathleen S., Harper, Stephen and Thomas, John E. (2024). First report of iris yellow spot virus infecting shallot (Allium cepa var. aggregatum) in Australia. Australasian Plant Pathology, 53 (6), 593-596. doi: 10.1007/s13313-024-00999-z
Harper, Stephen and Menzies, Neal (2023). Phytotoxic effects of Al on root growth are confounded in the presence of fulvic and humic acids. Soil Systems, 7 (3) 68, 1-15. doi: 10.3390/soilsystems7030068
Wibowo, Arif, Santika, Islaminati Anna, Syafitri, Luthfiana Mifta, Widiastuti, Ani, Subandiyah, Siti and Harper, Stephen (2023). Incidence of twisted disease and cultivation practice of shallot farmers in Bantul coastal area, Yogyakarta, Indonesia. Journal of Tropical Plant Pests and Diseases, 23 (1), 23-30. doi: 10.23960/jhptt.12323-30
Pangestuti, Retno, Sulistyaningsih, Endang, Kurniasih, Budiastuti, Murti, Rudi Hari, Harper, Stephen and Subandiyah, Siti (2023). Phenological growth stage of tropical shallot (Allium cepa L. Aggregatum group) planted from seed in lowland area based on the BBCH scale. Annals of Applied Biology, 182 (2), 257-266. doi: 10.1111/aab.12799
Syafitri, Luthfiana M., Wibowo, Arif, Widiastuti, Ani, Subandiyah, Siti and Harper, Stephen (2023). Short Communication: Molecular identification of Colletotrichum gloeosporioides causing anthracnose on shallot in Bantul, Yogyakarta, Indonesia. Biodiversitas, 24 (8), 4530-4534. doi: 10.13057/biodiv/d240855
Nguyen, Binh Thi, Harper, Stephen M., O'Hare, Tim J., Menzies, Neal W. and Wehr, Bernhard (2022). Sulfur nutrition affects garlic bulb yield and allicin concentration. Plants, 11 (19) 2571, 2571. doi: 10.3390/plants11192571
Nurulita, Sari, Geering, Andrew D. W., Crew, Kathleen S., Harper, Stephen M. and Thomas, John E. (2022). Detection of two poleroviruses infecting garlic (Allium sativum) in Australia. Australasian Plant Pathology, 51 (4), 461-465. doi: 10.1007/s13313-022-00870-z
Cheah, Zhong Xiang, Harper, Stephen M., Hare, Tim J. O’, Kopittke, Peter M. and Bell, Michael J. (2022). Improved agronomic biofortification of sweetcorn achieved using foliar rather than soil Zn applications. Cereal Chemistry, 99 (4), 819-829. doi: 10.1002/cche.10539
Nguyen, B.T., Hong, H.T., O’Hare, T.J., Wehr, J.B., Menzies, N.W. and Harper, S.M. (2021). A rapid and simplified methodology for the extraction and quantification of allicin in garlic. Journal of Food Composition and Analysis, 104 104114, 1-7. doi: 10.1016/j.jfca.2021.104114
Cremer, Julia, Campbell, Paul, Steele, Visnja, Persley, Denis, Thomas, John, Harper, Stephen and Gambley, Cherie (2021). Detection and distribution of viruses infecting garlic crops in Australia. Plants, 10 (5) 1013, 1-14. doi: 10.3390/plants10051013
Nurulita, Sari, Geering, Andrew D. W., Crew, Kathleen S., Harper, Stephen and Thomas, John E. (2020). First report of garlic virus E in Australia. Australasian Plant Disease Notes, 15 (1) 32. doi: 10.1007/s13314-020-00400-0
Cheah, Zhong Xiang, O’Hare, Tim J., Harper, Stephen M., Kochanek, Jitka and Bell, Michael J. (2020). Zinc biofortification of immature maize and sweetcorn (Zea mays L.) kernels for human health. Scientia Horticulturae, 272 109559. doi: 10.1016/j.scienta.2020.109559
Cheah, Zhong Xiang, O'Hare, Tim J., Harper, Stephen M. and Bell, Michael J. (2020). Variation in sweetcorn kernel Zn concentration a reflection of source-sink dynamics influenced by kernel number. Journal of Experimental Botany, 71 (16), 4985-4992. doi: 10.1093/jxb/eraa244
Salas, Rosario A., Godoy, Reyda Mae R., Salas, Felix M., Menzies, Neal, Harper, Stephen and Asio, Victor B. (2020). Yield and postharvest qualities of two genotypes of eggplant (Solanum melongena l.) applied with different levels of chicken dung. EnvironmentAsia, 13 (Special Issue 1), 81-86. doi: 10.14456/ea.2020.25
Cheah, Zhong Xiang, Kopittke, Peter M., Harper, Stephen M., Meyer, Gregor, O'Hare, Tim J. and Bell, Michael J. (2019). Speciation and accumulation of Zn in sweetcorn kernels for genetic and agronomic biofortification programs. Planta, 250 (1), 219-227. doi: 10.1007/s00425-019-03162-x
Cheah, Zhong Xiang, Kopittke, Peter M., Harper, Stephen M., O’Hare, Tim J., Wang, Peng, Paterson, David J., de Jonge, Martin D. and Bell, Michael J. (2019). In situ analyses of inorganic nutrient distribution in sweetcorn and maize kernels using synchrotron-based X-ray fluorescence microscopy. Annals of Botany, 123 (3), 543-556. doi: 10.1093/aob/mcy189
Hahuly, Mayavira V., Sumardiyono, Christanti, Wibowo, Arif, Subandiyah, Siti and Harper, Stephen (2018). Identification of purple blotch pathogen of shallot by PCR using specific primer for Alternaria genus. Archives of Phytopathology and Plant Protection, 51 (3-4), 103-121. doi: 10.1080/03235408.2017.1384196
Bich, Luong Bui, My, Hanh Phung Thi, Dinh, Rinh Pham, Minh, Trang Pham, Trong, Thang Do, Harper, Stephen, Wuhrer, Richard, Huang, Qingtao, George, Laurel, Holford, Paul, Zhao, Chen Chen, Mitchell, Christopher and Milham, Paul (2018). Trace metal contamination during grinding of plant samples. Communications in Soil Science and Plant Analysis, 50 (1), 102-107. doi: 10.1080/00103624.2018.1554671
Taranet, Prapa, Harper, Stephen, Kirchhof, Gunnar, Fujinuma, Ryosuke and Menzies, Neal (2017). Growth and yield response of glasshouse- and field-grown sweetpotato to nitrogen supply. Nutrient Cycling in Agroecosystems, 108 (3), 309-321. doi: 10.1007/s10705-017-9858-6
Vaughan, Sarah M., Dalal, Ram C., Harper, Stephen M. and Menzies, Neal W. (2011). Effect of fresh green waste and green waste compost on mineral nitrogen, nitrous oxide and carbon dioxide from a Vertisol. Waste Management, 31 (8), 1720-1728. doi: 10.1016/j.wasman.2011.03.019
Harper, S. M. and Blamey, F. P. C. (2008). A digital imaging technique to quantify the incidence of internal browning in potato (Solanum tuberosum) tubers. Experimental Agriculture, 44 (2), 157-166. doi: 10.1017/S0014479708006315
Harper, S., Kerven, G. L., Edwards, D. G. and Ostatek-Boczynski, Z. (2000). Characterisation of fulvic and humic acids from leaves of Eucalyptus camaldulensis and from decomposed hay. Soil Biology and Biochemistry, 32 (10), 1331-1336. doi: 10.1016/S0038-0717(00)00021-3
Diatloff, E., Harper, S. M., Asher, C. J. and Smith, F. W. (1998). Effects of humic and fulvic acids on the rhizotoxicity of lanthanum and aluminium to corn. Australian Journal of Soil Research, 36 (6), 913-919. doi: 10.1071/S98018
Harper, S.M., Edwards, D.G., Kerven, G.L. and Asher, C.J. (1995). Effects of organic acid fractions extracted from Eucalyptus camaldulensis leaves on root elongation of maize (Zea mays) in the presence and absence of aluminium. Plant and Soil, 171 (1), 189-192. doi: 10.1007/BF00009586
Conference Papers
Agarwal, R., Hong, H.T., Hayward, A., Harper, S. and O’Hare, T.J. (2024). Elevated zeaxanthin accumulation in fruit and leaf tissues of orange capsicum: can the leaf be used as a phenotypic marker for selection of high-zeaxanthin fruit?. XXXI International Horticultural Congress (IHC2022): IX International Symposium on Human Health Effects of Fruits and Vegetables - FAVHEALTH2022, Angers, France, 14-20 August 2022. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2024.1407.7
Gunadi, Nikardi, Harper, Stephen and Adiyoga, Witono (2024). Response of shallots to different rates of nitrogen grown in the lowland tropics of Cirebon Regency, West Java. 5th International Conference on Agricultural Engineering for Sustainable Agriculture Production (AESAP 2023), Bogor, Indonesia, 14-15 November 2023. Bristol, United Kingdom: Institute of Physics Publishing. doi: 10.1088/1755-1315/1386/1/012041
Nguyen, P. T., Bell, M. J. and Harper, S. M. (2023). Sensitivity of capsicum germplasm to magnesium deficiency growing in the solution culture. XXXI International Horticultural Congress (IHC2022): International Symposium on Plant Nutrition, Fertilization, Soil Management, Angers, France, 14- 20 August 2022. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2023.1375.18
Nguyen, B., Chu, M., Dang, H., Pham, P., Nguyen, D., Phan, H. and Harper, S. (2023). Effect of nitrogen rates on root yield of the medicinal plant Achyranthes bidentata. International Symposium on Medicinal and Aromatic Plants: Domestication, Breeding, Cultivation and New Perspectives, Angers, France, 14-20 August 2022. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/ActaHortic.2023.1358.18
Nguyen, Binh , Wehr, Bernhard , O'Hare, Timothy , Menzies, Neal , Hong, Hung and Harper, Stephen (2022). Benchmarking mineral concentration, bulb yield and quality across garlic genotypes. TropAg International Agriculture Conference, Brisbane, Australia, 31 October - 2 November 2022.
Agarwal, R., Hayward, A., Hong, H., Harper, S. and O'Hare, T. (2022). Designing high zeaxanthin capsicums. Brain and Ocular Nutrition Conference 2022, Cambridge, United Kingdom, 27-29 July 2022. Amsterdam, Netherlands: IOS Press. doi: 10.3233/JAD-229008
Nguyen, Binh, Dang, Ha, Pham, Phuong, Chu, My, Nguyen, Duyen, Phan, Hien, Wehr, Bernhard and Harper, Stephen (2021). Excess nitrogen application reduces root yield of Achyranthes bidentata. The Soil Science Australia and the New Zealand Society of Soil Science Joint Conference, Cairns, QLD Australia, 27 June - 2 July 2021.
Gonzaga, A.B., Gonzaga, N.R., Pepito, S.L.A., Octavio, R.I. and Harper, S.M. (2021). Growth, yield, and postharvest quality of cabbage (Brassica oleracea L.) in response to different levels of nitrogen fertilizer. III Asian Horticultural Congress - AHC2020, Bangkok, Thailand, 15-17 December 2020. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2021.1312.57
Gonzaga, N.R., Gonzaga, A.B., Pepito, S.L.A., Octavio, R.I. and Harper, S.M. (2021). Growth, yield and postharvest quality of tomato (Solanum lycopersicum Mill.) as influenced by different rates of nitrogen fertilizer. III Asian Horticultural Congress - AHC2020, Bangkok, Thailand, 15-17 December 2020. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2021.1312.48
Agarwal, Rimjhim, Hong, Hung T., Hayward, Alice, Harper, Stephen, Mitter, Neena and O’Hare, Tim J. (2020). Carotenoid profiling of orange-coloured capsicums: In search of high-zeaxanthin varieties for eye health. 1st International Electronic Conference on Food Science and Functional Foods, Online, 10–25 November, 2020. Basel, Switzerland: MDPI. doi: 10.3390/foods_2020-07717
Cheah, Z. X., Harper, S. M., O’Hare, T. J. and Bell, M. J. (2020). Elevated zinc concentration in zeaxanthin-biofortified sweetcorn kernels compared with a commercial hybrid. XXX International Horticultural Congress IHC2018: International Symposium on Fruit and Vegetables for Processing, International Symposium on Quality and Safety of Horticultural Products and VII International Symposium on Human Health Effects of Fruits and Vegetables, Istanbul, Turkey, 12-16 August 2020. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2020.1292.53
Agarwal, Rimjhim, Trieu, Hung Hong, Cave, Robyn, Harper, Stephen and O’Hare, Tim (2020). Orange capsicums and chillies as a potential source of dietary zeaxanthin, an important macular carotenoid for eye health. Third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, QLD Australia, 11-13 November 2019. Basel, Switzerland: MDPI AG. doi: 10.3390/proceedings2019036161
Djanie, Alina, Harper, Stephen and Cave, Robyn (2020). The effect of heat treatments and drip line placements on the yield and quality of garlic. Third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, QLD, Australia, 11 - 13 November 2019. Basel Switzerland: MDPI. doi: 10.3390/proceedings2019036120
Nguyen, Binh, Wehr, Bernhard, O’Hare, Timothy, Hong, Hung, Menzies, Neal and Harper, Stephen (2019). The relationship between bulb yield and allicin concentration in garlic varieties. Third International Tropical Agriculture Conference (TROPAG 2019), Brisbane, QLD, Australia, 11 - 13 November 2019. Basel, Switzerland: M D P I AG. doi: 10.3390/proceedings2019036028
Nguyen, Binh, Wehr, Bernhard, O'Hare, Timothy, Hong, Hung Trieu, Menzies, Neal and Harper, Stephen (2019). Allicin and yield: are they friends or enemies?. TropAg2019, Brisbane, QLD, Australia, 11-13 November 2019.
Mohd Nor, N.H., Fujinuma, R., Menzies, N.W., Harper, S. and McGrath, D. (2016). Selection for root morphological traits improves the growth of grafted bell pepper. XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): International Symposium on Plant Breeding in Horticulture, Brisbane, QLD, Australia, August 17, 2014. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/ActaHortic.2016.1127.33
Cave, Robyn, Hall, Zara, Qin, Malin and Harper, Stephen (2016). Influence of rootstock on photosynthetic activity and yield of Capsicum annuum 'Warlock'. International Symposium on Tropical and Temperate Horticulture, Cairns, Australia, 20-25 November 2016.
Somala, M. U. A., Wibowo, A., Subandiyah, S. and Harper, S. (2016). Nutrient budgeting of shallot (Allium cepa L. Aggregatum group) in Central and East Java, Indonesia. VII International Symposium on Edible Alliaceae, Nigde, Turkey , 21 - 25 May 2015. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/ActaHortic.2016.1143.45
Wibowo, A., Kaeni, E., Toekidjo, T., Subandiyah, S., Sulistyaningsih, E. and Harper, S. (2016). Responses of four shallot (Allium cepa L. Aggregatum Group) cultivars to moler disease (Fusarium spp.) after bulb treatment. VII International Symposium on Edible Alliaceae, Nigde, Turkey, 21 - 25 May 2015. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/ActaHortic.2016.1143.11
Roach, R., McTaggart, A., Gambley, C., Harper, S., Carey, D. and Duff, J.D. (2015). Pseudomonas syringae pv.porri: a new pathogen of Australian onions. XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): International Symposia on Innovative Plant Protection in Horticulture, Biosecurity, Quarantine Pests, and Market Access, Brisbane, QLD, Australia, 17-22 August 2014. International Society for Horticultural Science (ISHS). doi: 10.17660/actahortic.2015.1105.21
Vaughan, S. M., Harper, S. M., Dalal, R. C. and Menzies, N. W. (2014). To evaluate the effect of green waste compost on nitrous oxide emissions from horticulture. Ist international symposium on organic matter management and compost use in horticulture, Adelaide, Australia, 4-7 April 2011. Leuven, Belgium: International Society for Horticultural Science. doi: 10.17660/actahortic.2014.1018.6
Vaughan, Sarah M., Dalal, Ram, Harper, Stephen and Menzies, Neal (2010). Reduction of soil nitrogen losses from a Vertisol with organic waste amendments under subtropical conditions. 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Brisbane, Australia: International Union of Soil Sciences.