European
seed companies neglect the resistance to climate change when breeding wheat
varieties. Especially in Germany, but also in other European countries, the
cultivated varieties are susceptible to weather extremes such as heat, drought
or heavy rain, reports an international team of researchers in the
"Proceedings" of the US National Academy of Sciences
("PNAS"). The background is the rather one-sided breeding for
characteristics such as high yield, stalk stability or disease resistance.
Helena
Kahiluoto's team at the Technical University of Lappeenranta in southern
Finland (LUT) writes that food security also depends on field crops being able
to withstand extreme weather conditions. Climatic factors can explain about a
third to a half of yield fluctuations in Western Europe. Ultimately, this has
an influence on prices and thus on the food safety of the population.
The
research team, including members of the Leibniz-Centre for Agricultural
Landscape Research (ZALF) in Muencheberg near Berlin, evaluated systematic
field trials with soft and durum wheat varieties from 1991 to 2014 for their
resistance to weather extremes for nine countries - including Belgium, Denmark,
France and Slovakia. The evaluation included data from 140 fields in Germany
alone.
According
to the data, this weather-related resistance declined from the beginning of the
millennium in almost all the countries studied. The only exception was Finland.
The authors certify in particular that the Czech Republic, Germany, Spain and
Italy use varieties that are one-sidedly oriented towards yield and disease
resistance. They speak of a "diversity desert"..
„The
worrying decline in the ability to buffer the increasing weather variability
with the current portfolio of wheat varieties in Europe and to keep yields
stable even under extreme weather events is apparently an expression of too
one-sided a breeding," the authors write. Seed farms have set their
breeding targets to increase yield and disease resistance, not tolerance to
drought or high temperatures. They may have underestimated the increasing
climatic uncertainty.
The
resistance of wheat to climate-induced weather caprioles was simply
underestimated, emphasizes co-author Claas Nendel from ZALF. "It is very
difficult to breed a wheat variety that is resistant to all climatic influences
and at the same time offers high yields. This can only be achieved through a
large genetic diversity in the varieties and a high range of tolerances." Given
the predicted climatic changes, the current portfolio is not sufficient to
distribute the risk of weather-related yield losses well.
This
is not only true for the investigated parts of Europe. "We are constantly
observing large-scale weather-related crop failures worldwide that affect world
market prices," explains Nendel. However, the researcher assumes that seed
farms will react and adapt their varieties more strongly to climate
fluctuations if years with such extreme weather conditions as in the summer of
2018 become more frequent.
