Plant Growth Chambers for Wheat Research

Wheat (Triticum aestivum)

Wheat belongs to the grass family (Poaceae) and is composed of wild and domesticated grasses many of which have spread across the globe. The two primary types of wheat consumed today are Triticum aestivum (common/bread) and Triticum turgidum (durum/pasta) ⁽¹⁾. T. aestivum is further subdivided between spring and winter wheats, the latter requiring a cold treatment (vernalization) and thus are sown in the fall ⁽²⁾. Wheat is described as a “mid-tall annual or winter annual grass with flat leaf blades and a terminal flower” ^(2,3). However, domesticated wheats can now be described as a “short-mid” tall plant due to the green revolution whose goal was to feed the world. During the mid-20^th century Norman Borlaug, Nobel Prize winner and father of the Green Revolution, introduced the newly bred wheat lines that were semi-dwarf and disease resistant which helped reduce global starvation ⁽⁴⁾.

Wheat’s Importance & Challenges

Wheat is the most widely grown crop globally in terms of area and provides 20% of the world’s food calories and protein. To keep pace with population growth wheat production needs to double by 2050 ⁽⁵⁾. Continued genetic improvement of wheat is critical. In parallel with population growth, climate change is an added pressure for field crops. It is predicted to significantly reduce yields of the ‘big three’ (rice, maize and wheat) however wheat seems to be the most resilient ^(6,7). Periods of extreme heat, drought and waterlogging are problematic for wheat production as are new pests and diseases associated with local climate disturbances ⁽⁸⁾.

Wheat Research

The possibility of growing and breeding wheat in controlled environments was investigated by NASA at the University of Utah in the early 80s and their efforts resulted in a dwarf and tip-burn resistant wheat line (USU-Apogee) that can flower within 25 days when grown at 23°C under continuous light, PPFDs 510-930 μmol/m-2/s and 1000-1200 ppm CO₂ ^(9,10). While there isn’t consensus yet with respect to intensity and spectrum, wheat does best when grown at 21-23°C day and 18-20°C night and high CO₂ concentrations.

Breeding new lines of wheat in the field is a long process that can take over 12 years ⁽¹¹⁾. In greenhouses 1-3 generations per year are typical, however in controlled environments breeding protocols continue to improve. The term speed breeding (SB) was coined in 2003 at the University of Queensland where SB techniques were developed that included spectrum optimization, light intensity, photoperiod and temperature to accelerate photosynthesis and time to flower even further ⁽¹²⁾. Speed breeding of wheat resulted in 4-6 generations per year when practiced in controlled environmental conditions that are conducive to rapid growth and early flowering, and this can be accelerated by combining SB with genetic selection (SpeedGS) where new lines were released in 7.5 years ⁽¹¹⁾.

One SB Spring wheat protocol used an extended photoperiod of 22h (under HID or LED lights), PPFDs of 450-500 mmol/m²/s, day and night temperatures of 22°C and 17°C night, respectively and humidity levels of 60-70% to substantially reduce generation times ⁽¹³⁾. Winter wheat has a longer generation time than spring wheat due to the need for vernalization. Speed breeding protocols specific for winter wheat have been developed by combining vernalization duration, light intensity and photoperiod. Full generation times were on average under 100 days, compared to 128 days ⁽¹⁴⁾.

Common Research Topics

There are a variety of wheat research topics that are crucial for ensuring food security and advancing agricultural practices:

• Genetics and Breeding: Developing new wheat varieties with improved yield, disease resistance, and stress tolerance ⁽¹⁵⁾.
• Disease and Pest Management: Studying wheat diseases and pests and developing integrated management strategies ⁽¹⁶⁾.
• Abiotic Stress Tolerance: Researching how wheat can better withstand environmental stresses like drought, heat, and salinity ⁽¹⁷⁾.
• Crop Improvement: Enhancing wheat quality traits for better end-use applications, such as milling, baking and higher nutrient density ⁽¹⁸⁾.
• Sustainable Agriculture: Exploring practices that improve wheat production sustainability, including soil health and water use efficiency ⁽¹⁹⁾.
• Biotechnology: Utilizing gene editing and other biotechnological tools to improve wheat traits ⁽²⁰⁾.

Recommended Plant Growth Chambers

Medium sized reach in chambers to large walk-in plant growth rooms are suitable for wheat research. Medium to large controlled environments can accommodate larger plant populations and more complex experiments. Two tier rooms are ideal for mass screening and sizeable plant propagation programs as they enable researchers to effectively grow twice as much wheat as compared to a single tier model of the same size. Mature wheat can range in height from 2’ to 4’ (60 cm to 120 cm). Typical growth chamber and room alternatives include:

• BDW
• Conviron Growth House^TM
• EVO
• GR
• MTPS - 1 Tier
• MTPS Flex – 1 Tier
• MTPS Flex – 2 Tier & MTPS – 2 tier provides adequate growth height for shorter wheat plants
• PGC
• PGR
• PGW

Select Clients & Research

Suitable plant growth chamber models for wheat research have been used at the following universities and research institutes:

References

1. Vergauwen, D. and De Smet, I. (2017) From early farmers to Norman Borlaug – the making of modern wheat. Current Biology. 27: R853-R909.
2. USDA Economic Research Service.
3. Lersten, N.R. 1987. Morphology and Anatomy of the Wheat Plant. In: Heyne, E.G. (ed). Wheat and Wheat Improvement. American Society of Agronomy, Madison, WI pp. 33-75.
4. Somberg, J., Keeney, D. and B. Demspsey. (2012) Public agronomy: Norman Borlaug as ‘brand hero’ for the green revolution. The Journal of Developmental Studies. 48:11, 1587-1600.
5. Erenstein, O., Jaleta, M., Mottaleb, K.A., Sonder, K., Donovan, J. and H-J. Braun. et al (2022) Global Trends in Pheat production, Consumption and Trade. In: M.P. Reynolds and H-J. Braun (eds). Wheat Improvement. Food Security in a Changing Climate. Springer Nature Switzerland pp.47-68.
6. Jagermeyr et al. (2021) Climate impacts on global agriculture emerge earlier on new generations of climate and crop models. Nature Food. 2: 873-885.
7. Rezaei, E.E., Webber, H., Asseng, A., Boote, K., Durand, J.L., Ewert, F., Martre, P. and D.S. MaCarthy. (2023) Climate change impacts on crop yields. Nature Reviews Earth & Environment. 4:831-846.
8. Miedaner, T. and P. Juroszek. (2021) Climate change will influence disease resistance breeding in wheat in Northwestern Europe. Theoretical and Applied Genetics. 134:1171-1785.
9. Bugbee, B. and G. Koerner. (1997) Yield comparisons and unique characteristics of the dwarf wheat cultivar ‘USU-APOGEE’. Advanced Space Research. 20(10):1891-1894
10. Wheeler, R.M. (2014) NASA’s controlled environment agriculture testing for space habitats. Conference paper, International Conference on Plant Factory, Kyoto, Japan. Nov 10-12, 2014.
11. Alahmad, S., Rambla, C., Voss-Fels, K.P. and L.T. Hickey (2012) Accelerating Breeding Cycles. In: M.P. Reynolds and H-J. Braun (eds). Wheat Improvement. Food Security in a Changing Climate. Springer Nature Switzerland pp. 557-572.
12. Hickey, L.T. et al. (2019) Breeding crops t feed 10 million. Nature Biotechnology. 37: 744-754.
13. Ghosh, S. et al. (2018) Speed breeding in growth chambers and glasshouses for crop breeding and model plant research. Nature Protocols. 13: 2944-2963.
14. Schoen, A. et al. (2022) Reducing the generation time in winter wheat cultivars using speed breeding. Crop Science. 63: 2079-2090.
15. USDA Agricultural Research Service.
16. Ansari, M. et al. (2022) Current Trends in Wheat Research. IntechOpen.
17. Ibid.
18. USDA Agricultural Research Service.
19. Ansari, M. et al. (2022) Current Trends in Wheat Research. IntechOpen.
20. Langridge, P. et al. (2022), Meeting the Challenges Facing Wheat Production: The Strategic Research Agenda of the Global Wheat Initiative. Agronomy.