Plant Science Leaders - Chieri Kubota, Ohio State University

Dr. Chieri Kubota completed her BS degree in Agricultural Science, her MS degree in Horticultural Science and her PhD in Horticultural Engineering at Chiba University in Japan. After working for six years as a faculty member at Chiba University, she spent 16 years as a professor in the department of plant sciences at the University of Arizona as part of the Controlled Environment Agriculture (CEA) program. In 2017 Dr. Kubota joined the faculty in the Department of Horticulture and Crop Science where she is a College of Food, Agriculture, and Environmental Sciences (CFAES) Distinguished Professor and the Director for the Ohio CEA Center (OHCEAC). Dr. Kubota was elected as a Fellow of the American Society for Horticultural Science (ASHS) for her significant contributions to CEA. She has published over 250 scientific peer-reviewed articles and is very active in training and educating professionals both online and in on-site courses. The unique aspect of her research, which includes greenhouse strawberry production, vertical farm leafy green production and vegetable grafting physiology, is integrating technology, physiology and horticulture resulting in applicable data-based recommendations for high quality crops and profitability for CEA producers.

Conviron sat down with Dr. Kubota to discuss her career, her research as well as learn more about her fascinating role at the Ohio Controlled Environment Agriculture Center.

How did you move from engineering to horticultural research?

Early on I was focused on technology and have always been interested in technological history, the people behind the technology, who contributed and how technology moves from one country to another. However, when I was an undergraduate student at Chiba University, I met a professor that was working on tissue culture in small, controlled environment vessels. This professor, who later became the leader of plant factory growth in Japan, talked about thermal properties, temperature profiles, CO₂ mass balance and why plantlets need to have sugar in the media. I was hooked. Growing plants in controlled environments appealed to me because integrating technology into plant production systems leads to discoveries that are needed and that can be applied. The availability and advancement of Light Emitting Diode (LED) systems added a new and interesting layer of complexity to CEA. The effect of lighting on plant responses has been interesting and has provided another way to improve crop production using technology.

What have you found interesting from your recent work on strawberry lighting?

Strawberries are an interesting crop because of their physiological complexity. Strawberries are considered a new crop in CEA and are now becoming a tangible crop for indoor production. The two most frequent types of strawberries grown commercially are short-day (SD) and long-day (LD) types. The LD type, often referred to as everbearing (or “day-neutral”), is most commonly grown commercially both in the field and CEA. They can produce over many months for a more continuous harvest and generally produce less runners - making them more manageable. You don’t need to control flowering and when grown in CEA the Photosynthetic Photon Flux Density (PPFD) can be decreased while maintaining the desired Daily Light Integral (DLI) which can lead to healthy plants and energy savings. The SD type of strawberry, also known as June-bearing, produce runners during long days but require short days to flower. In open-field conditions, SD strawberries produce one large crop each year after a SD flower induction in the previous year and are good for larger short-term harvests. A benefit of SD strawberry types is the large amount of available germplasm. Over 90% of the strawberry accessions at the USDA-ARS National Clonal Germplasm Repository in Corvallis, Oregon are SD which offers a lot of cultivars to test and choose from. A pitfall of growing SD types in CEA is that continuous cultivation under short days induces semidormancy symptoms which include a reduced growth rate, smaller, thicker and more brittle leaves with shorter petioles and peduncles making the plant stunted and compact.

A recent open access paper published by my colleagues and I examined the effects of different photoperiods and light strategies with or without supplemental far-red light (FR) on the productivity and quality of SD strawberry types in controlled indoor environments (Lin et. al. (2025). Two SD cultivars were selected and grown under continuous SD, alternating SD/LD every 5 weeks and continuous LD, after initiating flowers under SD. Plant structure was improved under continuous LD or alternating SD/LD treatments compared to continuous SD and did not affect yield or fruit quality. Supplemental far-red (FR) light reversed semidormancy morphological effects in only one cultivar, but it increased yield and sugar contents in both cultivars. So, different strawberries cultivars respond differently to spectra. We need to further explore how to optimize the amount and timing of FR light supplementation for further improvements to yield, quality and possible energy savings.

What are some strawberry grower challenges and questions?

It took us two years to learn enough about growing tomatoes in CEA to be able to help beginning growers through courses and publications. Strawberries are complicated and it took us 4-5 years before understanding the basics about this crop to a degree that we could teach others. The primary questions we get are about fertigation management, how plants behave under certain conditions, what cultivar to grow, how many kilos can be expected, what kind of transplants should be used and where to get them from. To answer these questions, we set up a strawberry information website that answers many of these and more to help growers so that during the Strawberry School Online series we can dig deeper and teach further advances strawberry production.

Reference to Dr. Kubota’s article on FR light and strawberries:

Lin, Y., Barker, D. J., & Kubota, C. (2025). Supplemental Far-red Light Prevents Semidormancy and Enhances Yield and Fruit Quality of Short-day Strawberry in Indoor Production. HortTechnology, 35(5), 663–670. https://doi.org/10.21273/HORTTECH05698-25