A first-of-its-kind analysis of the untapped genetic potential of wheat
shows global yields are only half of what they could be.
The team of international experts, led from the UK‚??s Rothamsted
Research, says this ‚??genetic yield gap‚?? could be closed by developing
wheat varieties tailored to each region - by utilizing the vast genetic
variation available in global and historical wheat gene banks with
modern techniques such as speed breeding and gene editing.
Dr Mikhail Semenov and Dr Nimai Senapati, who co-led this study, define
a crop‚??s ‚??genetic yield potential‚?? as the highest yield achievable by an
idealised variety ‚?? in other words, a plant with an optimal genome that
allows it to capture water, sunlight and nutrients more efficiently than
Dr Semenov said: ‚??Current wheat cultivars are, on average, only at the
half-way point with respect to the yields they could produce given the
mismatches between their genetics and local wheat growing conditions.
‚??Global wheat production could be doubled by the genetic improvement of
local wheat cultivars - without increasing global wheat area.‚?Ě
Using existing data on the contribution of different genes to individual
plant traits such as size, shape, metabolism and growth, the researchers
ranmillions of computer simulations to design ‚??perfect‚?? wheat plants
] were tailored
to their local environments.
When compared to the performance of locally adapted cultivars, in all
cases they found current wheat varieties were underperforming for grain
yield, with an obvious ‚??genetic yield gap‚?? between reality and possibility.
According to Dr Senapati, closing the genetic yield gap would go a long
way to feeding the growing world population and would reduce pressure to
convert wild habitats to farmland.
Wheat is the world‚??s most widely grown crop, and in terms of human
consumption, is the second most important crop after rice, with global
harvests in the region of 750 million tons.
Since the 1960s ‚??Green Revolution‚?? yield have, on average, tripled ‚?? but
this study suggests there is a lot more to come.
It is the first time this type of analysis has been done globally with
the study, published in/Nature Food/, looking at a total of 53 wheat
growing regions across 33 countries and covering all global wheat
Using a state-of-the-art wheat model, called Sirius, the team first
calculated the potential yield from a total of 28 commonly used wheat
varieties grown at these sites, assuming the best possible cultivation
conditions for each one.
This gave harvests of less than four tons in Australia and Kazakhstan -
compared with 14 tons of wheat produced per hectare in New Zealand.
Next, they designed ‚??idealized‚?? local varieties within their model,
which optimised several plant traits that contribute to yield and whose
underlying genetics will allow them to be improved by plant breeders.
Simulations were based on extensive data on the natural genetic
variation underpinning the traits. These included tolerance and response
to drought and heat stresses, the size and orientation of the
light-capturing upper leaves, and the timing of key life cycle events.
The results showed that by optimizing these key traits, genetic yield
gaps could be anywhere from 30-70% across different countries, with a
global average genetic yield gap of 51%. Therefore, global wheat
production could be doubled by exploiting this existing genetic yield
gap towards achieving global food security in a sustainable way.
‚??Not unsurprisingly, the countries with the lowest current yields could
gain the most from closing their genetic yield gaps,‚?Ě said Dr Senapati.
‚??That said, even improvements in those countries with a medium genetic
yield gap of 40 to 50%, but with a large proportion of global wheat
harvest area - such as the leading producers India, Russia, China, USA,
Canada, and Pakistan - would have a substantial effect on global wheat
production due to the larger wheat cultivation areas involved.‚?Ě
Before this study, the size of these genetic yield gaps at country and
global scales were unknown.
The genetic yield gap idea contrasts with the longer-understood concept
of traditional yield gap due to sub-optimal management where harvests
are smaller than the best-case scenario as a result of factors such as
pest or diseases, lack of nutrients, or sowing or harvesting at the
‚??Our analysis suggests that such genetic yield gaps due to sub-optimal
genetic adaptation could, in relative terms, be as large as the
traditional yield gap due to imperfect crop and soil management,‚?Ě said
‚??Wheat was first domesticated about 11,000 years ago, but despite this ‚??
and not to mention the sequencing of its entire genome in 2018 ‚?? the
crop is still some way from being at its ‚??genetic best‚??,‚?Ě he added.
Also involved in the study were leading wheat experts from Australia,
Denmark, France, Germany, The Netherlands and Mexico.