Wheat is the most widely cultivated crop in the world. The high yields produced in intensive European wheat cultivation are crucial to global food security. Yet how can the required production volumes of high-quality food crops like wheat be achieved despite a significant reduction in the input of agrochemical products such as fertilisers and plant protection products? This question is becoming increasingly important in terms of more sustainable farming.
New findings of the research project “Briwecs” show that new wheat varieties that have been improved through breeding produce higher yields than old varieties with reduced use of agrochemicals. New wheat varieties stand out for their improved disease resistance, increased nutrient use efficiency and even the highest yields under drought stress. Experimental Farm Hohenschulen of the Faculty of Agricultural and Nutritional Sciences at Kiel University (CAU) is also involved in the research project “Briwecs”. The results were published in the journal “Nature Plants” on 17 June under the title “Breeding improves wheat productivity under contrasting agrochemical input levels”.
The criticism that modern crop varieties are only productive in intensive farming because of the strong focus on increasing yields is often heard in public discussion. Older varieties, by contrast, are attributed with better adaptability and efficiency in cultivation systems with reduced input of fertilisers or plant protection. In one of the world’s largest such studies to date, around 220 major Western European wheat varieties from the last 50 registration years were grown at various locations for several years. Unusual features of the study: the yield of each variety was checked not only under optimal growing conditions but also with significantly reduced input of nitrogen fertilisers and without treatments with plant protection products. In this way, the research teams were able to directly compare the yields of the varieties under different farming intensities and produce a direct link between many years of breeding progress with efficient use of resources and plant protection requirements.
Led by Professor Henning Kage from the Institute of Crop Science and Plant Breeding at Kiel University, around 220 wheat varieties were grown on more than 2,000 plots at Hohenschulen. “We were able to clearly demonstrate that new wheat varieties produce better yields than old varieties under extensive conditions, i.e. with less fertiliser and without plant protection. It can also be assumed, therefore, that organic farming does not require specially bred wheat varieties,” said Professor Kage. Doctoral researcher Till Rose regularly had a drone fly over the 2,000 plots for the studies. “With the drone, it was possible to measure the light reflections of four different wavelengths and the temperature of the wheat. Though the best way of calculating the corn yield is still with the combine harvester, using the drone, we also discovered a few things about how the varieties produce the different yields. In this way, farmers can select parents for new hybrids that complement their positive features,” explained Rose.
The results correspond with the expectations
In intensive farming, the agricultural researchers demonstrated an average yield increase for new varieties of around 32 kg/ha per registration year. This explains a large proportion of sustained production increases over the last 50 years and is also reflected in the conditions of variety registration. In order to register new varieties, the official approval authorities require an improvement on previous varieties.
The yield data from the varieties with reduced inputs of agrochemicals, however, revealed a great surprise.
Here, contrary to expectation, the breeding-based yield increase was not lower, but rather just as high as or even higher than in intensive farming. What was noticeable was that it was by no means the older varieties but always the newest ones that demonstrated the highest yield – and they achieved this without fungicide treatment or with less fertiliser. Obviously – according to the researchers’ explanation – intensive breeding for yield has also indirectly improved the overall performance of the varieties under various situations of stress or shortage. Newer varieties also stood out for their better yield stability.
Those involved in the project were able to use their expertise to provide a clear recommendation for the cultivation of European wheat against the backdrop of climate change and agricultural policy change: sustainable and resource-efficient farming with a reduced input of agrochemicals only works when using the newest, best-performing varieties.