How dynamic speed breeding programmes will bring back biodiversity
In our new series, we’re focussing on a variety of issues around agriculture and our current food systems to begin exploring how we might solve them. Our first two articles looked at the issues with ‘organic’ farming and questioned whether it really is better and the variety of issues around pesticide usage. We continue to believe that dynamic solutions for food production will be found by working collaboratively towards a more sustainable and food-secure future.
Today, we turn our attention to speed breeding, a food system which promises to develop new crop varieties faster, offering further hope for biodiversity and food security.
A fast-growing global population, a dramatic rise in extreme weather events as a result of climate change and a global pandemic have collided to usher in a much needed conversation around food security. There is a need to significantly increase the improvement rate of many important food crops to meet demand. However, traditional breeding is too slow and inadequate to meet this increasing demand.
Plant breeding combines a delicate blend of art and science to bring together desired genetics and plant characteristics in hopes of generating a superior product. In perennial crops like soft fruit, this process can take 10–15 years from the time of the initial cross to the release of a new and improved variety. This means that the traits and genetics we are striving for and screening for today will need to be robust enough to be grown in a climate 15 years from now.
What is speed breeding and how does it help us?
Speed breeding is the production of successive plant generations over a shorter period of time; the time to get from ‘seed to seed’ is considerably shorter than in traditional breeding programmes. Speed breeding would allow us to produce new crop varieties with improved traits such as pest and disease resistance/tolerance, drought tolerance and nutritional characteristics over a considerably shorter time period than traditional breeding methods. It allows us to produce several generations of a crop in a period of months compared to only one new generation per year.
For example, it can take up to 5 years to get a blueberry crop from a seed to a fully established plant that can be profitable for a grower. Speed breeding would enable the plants to potentially be ready in half the time. Economically, this would greatly benefit growers because they would have higher yields of healthier, hardier crops which are likely to incur fewer losses due to improved disease resistance and therefore greater profit. More profit would result in the reinvestment of further techniques to improve the quality, diversity and yield of crops. This also provides exciting possibilities for the long-term improvement of crop production and allows new scientific methods of improvement to be adopted.
Extending the duration of plant exposure to light within a daily cycle and combining this with an early seed harvest reduces the generation times in some ‘long day’ (LD) and day neutral crops. In ‘short day’ crops (SD), light extension can be used to encourage plant photosynthesis and vigorous vegetative growth before the light spectrum is used to target stem growth and flowering.
Speed breeding was first applied commercially in wheat and has traditionally been used for long-day and day-neutral crops such as barley, canola and chickpea. It is thought that speed-breeding could be applied to any species; it’s just a matter of adapting the protocol to suit the plant and the growth conditions that it requires. Adaptation of protocols for short-day crops would be particularly beneficial for crops such as sorghum and millet, which are grown predominantly in Africa and Asia. Being able to produce these plants with increased drought tolerance or increased yield and have them growing in the field within a couple of years would be incredibly beneficial for increasing the global food supplies.
Why is speed-breeding so important?
Speed breeding allows for greater sustainability of plant products. The techniques which it requires allow new and improved crop varieties to become available faster. As a large part of breeding aims to promote crop yield, this is vital for feeding an ever growing population.
Ultimately, it means that crop improvements happen quicker and therefore the benefits are also reaped much sooner. If we were to continue using solely traditional methods of breeding, there is a chance that losses due to pests and diseases could increase every single year. This is because pests and diseases may overcome host resistance or the pesticides used to control them may become banned (as many already have been). If either or both of these occur, the consequences on the amount of crop available as a food resource will be drastic.
How vertical farming can help
Currently, speed breeding largely takes place in glasshouses or growth cabinets. These are used to provide controlled environments for the plants to grow in and replicate their ideal growing conditions so they grow as quickly as possible. A problem with this method is that, often, large banks of high pressure sodium (HPS) lamps are used which produce too much heat and not enough light. Moving speed breeding to a Totally Controlled Environment Agriculture (TCEA), or vertical farming, system could be particularly important in future speed breeding programmes.
Vertical farms use energy efficient LED lighting, which produce considerably better quality of light for plant growth; the light spectra can often be tailored specifically to the crop of interest. Lights can be water cooled, reducing heat loss, so that plants are not subject to excess heat. Within vertical farms, all of the water, nutrients and lighting can be precisely controlled to give the plant the optimal conditions it needs for growth. Combining this with speed breeding could shorten the time between generations of crops even more.
At the moment, speed breeding is considered too expensive to scale up extensively for food production. Glasshouses incur large running costs (maintenance, lighting, air-conditioning), therefore, using them for speed breeding is not cost effective yet. Breeding programmes have been in decline because they are seeing decreases in funding and personnel according to a team of scientists led by Kate Evans, a Washington State University horticulture professor. This is potentially detrimental to biodiversity as speed breeding is able to help expand crop diversity by tracking genes, so that more robust and productive crops can be developed faster than traditional approaches allow.
However, moving speed breeding to vertical farms could see a reduction in cost. TCEA has the capacity to make important energy and waste reduction efficiencies with LED lighting systems and micro-climate control that can be optimised for the crop and the recycling of water and optimised nutrient delivery. This means they are perfectly positioned for facilitating the next generation of speed breeding programmes which will secure significant crop improvement and biodiversity. Furthermore, if we combine this with a reduction in costs for field trials by selecting more robust and resilient plants to establish and flower quicker than conventional selections, the argument for investing in TCEA-led speed breeding programmes becomes more compelling.
Combining food systems
Speed breeding has the potential to be a significant tool for scientists to produce a greater diversity of improved crops and to produce them quickly. Speed breeding alone isn’t going to the oncoming food crisis or even single-handedly deal with the biodiversity crisis but it certainly has the potential to be a significant part of the solution. We will need to combine speed breeding with traditional breeding strategies, modern analytical software and TCEA in order to respond to these oncoming crises and understand how we all have important parts to play.
A couple months ago, Liberty Produce collaborated with Susan McCallum from The James Hutton Institute for their Fruits of The Future event in a video explaining what speed breeding is, why it is important and how it can speed up germination time for blueberries! Check it out: Sowing the seeds for speed breeding in vertical farms
