Less rain and rising temperatures: climate change also affects grain crops. After maize and rice, wheat ranks third in international grain production. To date, older varieties were considered more profitable and particularly resistant to stress. However, findings of the research project "BRIWECS" indicate that with a reduced amount of agrochemicals, new wheat varieties enhanced through breeding achieve higher yields than old ones. The project is led by Professor Hartmut Stützel from the Institute of Horticultural Production Systems at Leibniz University Hannover. Over a period of five years, "BRIWECS" received approximately four million euros of funding from the Federal Ministry of Education and Research (BMBF).
High-yielding wheat crops in Europe are crucial to ensure global food security. But how can the necessary output of high-quality food crops such as wheat be achieved while using significantly less agrochemicals such as fertilizer and pesticides? This question is particularly important when it comes to promoting sustainability in agriculture.
In the public debate, critics often argue that due to the focus on yield increase, modern plant varieties are only profitable in intensive farming. Older varieties are said to be more adaptable and profitable in cropping systems with reduced input. To date, researchers lacked the empirical data necessary to support decision making with regard to breeding specific varieties for more sustainable crops. In order to fill this knowledge gap, agricultural scientists in various locations have examined the influence of progress in breeding on the potential yield in sustainable crop scenarios.
In one of the largest studies to date and over a period of several years, researchers cultivated almost 200 major Western European varieties of wheat covering the last 50 years of national listing. The study was carried out in various locations such as Ruthe, a research station of Leibniz University Hannover. What make the study unusual is that the yield of each variety in each location was tested not only in ideal, intensive farming conditions, but also in direct comparison to scenarios with substantially reduced nitrogen fertiliser or without pest control treatments. Thus, researchers were able to directly compare the yields of the varieties in different crop intensities and establish a direct connection between long-term breeding progress, resource efficiency, and pest control requirements.
Some findings of the study are consistent with the expected results. In intensive farming, agricultural scientists observed an average yield increase in newer varieties amounting to approximately 32 kg/ha per year of national listing. This accounts for a large proportion of the continuing increase in production over the last 50 years, which is also reflected in the requirements for admission to the national list. In order to be admitted to the national list, regulatory authorities require new varieties to be a clear improvement over existing varieties.
However, yield data from crops where a reduced amount of agrochemicals was used, came as a surprise. Contrary to all expectations, the increase in yield achieved through breeding was not smaller, but just as large or even larger compared to intensive farming. Without exception, not the older but the newest varieties achieved the highest yields - irrespective of whether fungicides were used or whether fertilisation was reduced. Overall, newer wheat varieties demonstrated an improved resistance to diseases, a more efficient use of nutrients, as well as the highest yields under drought stress. According to researchers, intensive yield-oriented breeding indirectly improved the overall productivity of the varieties in the event of stress or shortages. In addition, newer varieties produced crops with higher yield stability.
Through an in-depth analysis of the varieties' genotypes, researchers were able to reveal the genetic background of this phenomenon. Apparently, through long-term yield-oriented selection in extremely different growing conditions, a constant accumulation of beneficial genetic variants occurred over time. The individual effects were rather insignificant; however, the overall increase had a positive effect on sustainability characteristics such as water or nutrient efficiency. Furthermore, researchers found that the gene pool of modern varieties has enormous potential for further improvements.
Other project partners include Kiel University (CAU), Giessen University (JLU), Julius Kühn Institute (JKI), Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), and University of Bonn.
Note to editors:
For further information, please contact Professor Hartmut Stützel, Institute of Horticultural Production Systems at Leibniz University Hannover (Tel. +49 511 762 2635, Email stuetzel@gem.uni-hannover.de).
