Protecting organic seeds: Research on seed treatments for organic farming

Summary

Seeds represent the fundamental basis of agricultural production, accounting forapproximately 90% of the world’s food crops. However, seeds can also serve as a vehicle forthe transmission of plant pathogens that pose a threat to food production. Seedbornepathogens infect seedlings after seed germination, causing diseases that affect both yieldsand crop quality, and therefore have a significant impact on farmers’ incomes and foodsecurity. Furthermore, seedborne pathogens can disseminate within agricultural fields,infecting other plants, and they can often survive in the soil for long time periods until theyencounter new hosts and initiate further infections. Despite the implementation of preventivemeasures to avert the transmission of diseases, the presence of pathogens on seeds and insoil can be inevitable.
In conventional agriculture seeds are treated with chemical fungicides to protect against bothseed-borne and soil-borne diseases. However, organic agriculture demands alternativeapproaches avoiding the use of artificial inputs and that should adhere to European organicregulations. These treatments primarily involve the use of natural compounds (e.g., plantextracts, plant oils, chitosan), physical treatments (e.g., mechanical, thermal), or theapplication of beneficial microorganisms. While these treatments can be highly effectiveagainst certain diseases in specific crops, some crops or crop-pathogen systems still needsolutions suitable for an organic production. Furthermore, treatments that are effectiveeradicating seed pathogens can sometimes have unintended negative effects on seedhealth, such as reducing seed vigor, or negatively impacting the natural seed microbiome,which can also have beneficial roles in seeds. Consequently, further research is necessary toidentify novel seed treatments against specific diseases affecting organic crop production.
At the Research Institute of Organic Farming (FiBL) we are investigating new organic seedtreatments. Our two primary areas of focus are protecting seeds against soil-bornepathogens, and disinfecting seeds infected by seedborne pathogens. In the SeednSoilproject, which is funded by Fenaco, the focus is on investigating seed treatments that protect wheat seeds from soil-borne infections, such as common bunt disease (caused by Tilletiacaries ) and snow mold disease (caused by Microdochium nivale ). These diseases have thepotential to cause considerable yield losses in organic farming. In the EU-funded projectLiveSeeding, the objective is to investigate novel seed treatments to sanitize seeds of variousvegetables, and thereby, provide protection against seedborne diseases. These treatmentsare developed to be compatible with the facilities of seed companies, by working togetherwith seed companies in Switzerland (Sativa Rheinau AG), Germany (Bingenheimer SaatgutAG) and Greece (Oikos seeds). Seed treatments with protective potential against plantpathogens have been identified in both projects. These results will be presented.