Just how much does enhancing photosynthesis improve crop yield?

Just how much does enhancing photosynthesis improve crop yield?
Dr. Alex Wu conducting research in a wheat field. Credit: ARC Centre of Excellence for Translational Photosynthesis

In the next two decades, crop yields need to increase dramatically to feed the growing global population. Wouldn't it be incredibly useful if we had a crystal ball to show us what are the best strategies available to increase crop yields?

A team of scientists have just developed exactly that: a that predicts which photosynthetic manipulations to plants will boost the yields of wheat and sorghum .

"We have developed a reliable, biologically rigorous prediction tool that can quantify the yield gains associated with manipulating photosynthesis in realistic crop environments," said Dr. Alex Wu, from the ARC Centre of Excellence for Translational Photosynthesis (CoETP) and The University of Queensland (UQ).

Plants convert sunlight, carbon dioxide and water into food through photosynthesis and several studies have shown that this vital process can be engineered to be more efficient.

"Until now, it has been difficult to assess the impacts of these manipulations on crop yield. This prediction tool will help us to find new ways to improve the yields of food crops around the world."

Dr. Wu, the lead author of the paper published this week in the journal Nature Plants, said that this modelling tool has the capacity to link across biological scales from biochemistry in the leaf to the whole field crop over a growing season, by integrating photosynthesis and crop models.

"It is a powerful tool to assess and guide photosynthetic manipulations and unravel effects that confound the relationship between photosynthetic efficiency and crop performance, "he said.

Centre Deputy Director Professor Susanne von Caemmerer said one of the study's most innovative aspects was using a cross-scale modelling approach to look at the interactions between photosynthesis and the pores of the leaf that allow the exchange of CO2 and .

"We know that it is not as simple as saying that improving photosynthesis will increase yield. The answer depends on the situation," said Professor von Caemmerer, a researcher at The Australian National University (ANU) who is a co-author of the study.

Just how much does enhancing photosynthesis improve crop yield?
Dr. Alex Wu researching in the field. Credit: ARC Centre of Excellence for Translational Photosynthesis

"For example, we found that in crops like sorghum, more photosynthesis can actually decrease yield in water-limited cropping situations. The modelling predicts that we can manage this yield penalty if we can also maintain a stable rate of carbon dioxide entering, or water vapour exiting, the pores of a leaf."

Co-author and Centre Chief Investigator Professor Graeme Hammer from UQ said this study fosters the type of transdisciplinary research needed for future crop improvement.

"It links research across the whole Centre, which has a main focus to increase the yield of major staple crops such as wheat, rice, sorghum and maize by enhancing photosynthesis."

"Now that we have developed and tested this predictive model, our next step is to work closely with collaborators at the CoETP to design simulation scenarios that test the effects of other bioengineering and breeding trait targets," Professor Hammer said.

One of those collaborators is ANU Professor Graham Farquhar, who co-authored the study.

"In this study we are scaling up to the whole crop growth season and incorporating the feedback effects on photosynthesis of resources for the crop, such as water, which is critical in predicting consequences on crop productivity in future Australian crop environments", said Centre Chief Investigator Professor Farquhar from the ANU Research School of Biology.

The team investigated three main manipulation targets—enhancing the activity of the main photosynthetic enzyme, Rubisco; improving the capacity of the leaves to transport electrons; and improving the flow of (CO2) through the internal layers of the leaf.

"This study permits us to quantify the consequences on crop yield for these three targets and their combinations for wheat and sorghum crops for irrigated or dryland cropping environments," said Dr. Wu.

The team found crop yield changes ranged from a reduction of one per cent to a 12 per cent increase, depending on the combination of photosynthetic targets, the crop and environmental conditions such as water availability.

Explore further

Designing a more productive corn able to cope with future climates

More information: Quantifying impacts of enhancing photosynthesis on crop yield, Nature Plants (2019). DOI: 10.1038/s41477-019-0398-8 , https://www.nature.com/articles/s41477-019-0398-8
Journal information: Nature Plants

Citation: Just how much does enhancing photosynthesis improve crop yield? (2019, April 8) retrieved 20 August 2019 from https://phys.org/news/2019-04-photosynthesis-crop-yield.html
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Apr 08, 2019
This is not what is needed. Successful farmers owning thousands of acres of lands and using the most modern Equipment instead of importing arms & ammunition for wars is preferred. Once jobs are lost for the illiterates because of this practice, they should be sent to schools to study up to Doctorate degrees in Scitech fields. All these years, farmers in developing countries have been owning 5-50 acres of land each and cultivating using abundant manual labor unlike in developed countries. Machines can do better.

Apr 08, 2019
Why would you think the only way to improve yields is mechanization? We can certainly persue more than one strategy at a time to increase yields. Increased photosynthesis efficiency looks to be a very good thing to tap, once we understand the where it is and isn't useful.

Apr 09, 2019
The biggest issue is not increasing food, but decreasing population density. All these 7+ BILLION people are causing all the problems, and they want to find more ways to increase their numbers.

What is wrong with this picture?

Apr 09, 2019
In simple terms, the more humans you feed, the more humans you breed. There seems no end to the skyrocketing population.

Sooner or later nature will intercede and dump billions of people through starvation, disease and lack of potable water, and all the violent strife that will result from this. Due to the ignorance of the world's leaders in neglecting this most significant issue of all, there is nothing to do but watch and/or take part in the pending calamity.


Apr 09, 2019
Why would you think the only way to improve yields is mechanization?

I guess this is a response to the blocked comment, but precision farming with high mechanization and GMO are the best methods to decrease farming environmental footprint (higher yields, minimized pesticides, less area, less nutrient leakage). Of course we would like to see electric vehicles soon!

The biggest issue is not increasing food, but decreasing population density.

That process has been in progress for a long time, so the article - and you - is somewhat alarmist. The birth (and child death) rates have been decreasing steadily with education, and societies like Japan and Germany has an inverted population demographics.

China, which caps the global demographics, is set to get decreasing population 2030ish, despite removing the "one child" law [ https://www.abc.n...10687996 ].

Apr 10, 2019
@torbjorn_b_g_larsson , Germany and Japan, with Italy and a few others, reduced the population of the planet by about 60 million back in the early-to-mid 1940s. In 1940, the global population was ca. 2.5 billion. Despite the deaths of WWII, it hardly put a dent in the number of people.

That they are trying again in a different way is not going to be particularly useful since they only represent a fraction of the global population, and are also highly educated. The mass of humanity exists in very poorly educated populations, and most raise large families.

China's experiment with one child only helped to some extent - it produced a lot of male children (girls were not wanted). These males cannot find Chinese women to breed with. But that too is a drop in the bucket. Unlikely they will make further progress.

People believe it is a right to have kids. Go ye forth and multiply yourself into extinction seems to be the faith. Sadly, nature's course is the most likely.

May 20, 2019
The rate of population growth is decreasing as nations like China and India reach equilibrium and decline. Its really now up to Africa and the Middle East to cease growth and we are there, the OECD is in negative growth. Give power to women and decrease the child mortality rate and grow stabilizes or declines. As Simple as that.
Do that and in thirty years time we will be complaining about where did all the people go.

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