2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Long-term work of breeders seeking to develop the most productive varieties has led to a decrease in the genetic diversity of wheat and its resistance to climate change, European scientists write in an article published in the journal Proceedings of the National Academy of Sciences.
Food security is largely determined by the yield of the main crops. Climate change leads to changes in the weather, and, as a result, inconsistent harvest and food prices, and hence their availability. Uncertainty that food will be affordable is causing waves of migration and political instability. Today, breeding methods can provide sufficient levels of wheat yield in the current climatic conditions, but the climate is changing and many popular varieties may become insufficiently productive.
Europe grows one-fifteenth of the world's wheat. Climate change explains 31-51 percent of the deviation from the average wheat yield in Western Europe and 23-66 percent in Eastern Europe. In southern Europe, climate change is responsible for 15 to 45 percent of yield fluctuations in Italy and Greece, and in southern Spain, more than 75 percent. However, the resistance of these crops to climate change in Europe has only now been studied.
Helena Kahiluoto of Lappeenranta University of Technology and colleagues from other European universities analyzed wheat yield data in nine countries - Finland, Denmark, Germany, Belgium, Czech Republic, France, Slovakia, Italy and Spain. The complete data set consisted of almost 11 thousand numbers - the amount of wheat harvested per hectare, which were compared with data on temperature, humidity, time and other parameters. Scientists used data on 991 varieties of winter and spring wheat, durum wheat that were grown between 1991 and 2014, in 636 locations in nine countries, as well as weather data in their areas of cultivation in eight countries. At the first stage of the study, the scientists selected the factors of climate change that have the greatest impact on the harvest (humidity, minimum temperatures at different times of the year, temperature drops). They then quantified the impact of climatic factors on yields.
Reducing the resistance of wheat to climate change in Europe. The green dashed line indicates the variety of crops, the red - the reaction to critical weather factors.
The scientists found that wheat's resistance to weather changes began to deteriorate in the early 2000s, with the effect most pronounced in the Czech Republic, where it has been visible since 2002. In Germany, the decline began in 2003, in Spain in 2005 or even earlier (no data available before this year), in Slovakia in 2006, and Denmark in 2009. Finland was the only country where wheat resilience to climate change was growing. although the diversity of cultures in this country was the smallest. The negative reaction of all crops in all countries to the increase in humidity was especially sharp. Wheat is very sensitive to high humidity, which is conducive to the spread of diseases.
The reason for the poor adaptability of plants to climatic changes, according to scientists, is a decrease in genetic diversity. Breeding in favor of several desirable characteristics of the culture impoverishes the gene pool by eliminating the eliminated alleles. Wheat genetic diversity began to decline after the 1990s. Researchers attribute this decline to an increase in the number of small wheat producers. Increased competition forced the production cycle to be shortened without wasting time on technological improvements. Scientists have discovered "deserts" of genetic diversity in the Czech Republic, Germany, Italy and Spain.
The authors of the study argue that current breeding methods are worth revising, as they are not suitable for increasingly less predictable climate changes. Therefore, according to scientists, governments need to make the regulation of the work of breeders more flexible and organize a constant exchange of data on crop yields and their resistance to climate change. Producers, the authors of the article believe, should pay more attention to the choice of crops they grow. However, further research is needed to understand the genetic basis for yield and weather tolerance.
Scientists have already reported similar cases of biodiversity loss due to artificial selection. For example, corn breeders in North America have developed a crop with high yields but poor adaptability to changing environmental conditions.
