Healthy seed for organic production of cereals and legumes.

Seed borne diseases can cause serious problems in production of cereals and legumes. In conventional agriculture these diseases are intensively controlled by seed treatment, but this is not an option in organic agriculture. Current practice in organic agriculture is to analyse the seed by seed health testing and to discard the seed lot if the infection by diseases exceed the threshold levels, where seed treatment are recommended in conventional agriculture. A huge number of propagated organic seed lots are discarded using this practice, in some crops and years almost all seed lots are discarded. Most years, the quantities of organic seed are insufficient to supply the market because seed lots are discarded for infections by seed borne diseases. In these cases it is allowed for the organic farmers to use conventional propagated seeds. However, after December 2003 this will no longer be accepted by certifying bodies, and only organic seeds can be used in the EU.

The threshold levels used are developed under the presumption that pesticides can be used in case of later disease development in the crop, and no experiments has been made to confirm if the same threshold levels apply under organic farming practice. The project will investigate these thresholds in field trials for all relevant diseases in peas and small grain cereals, and evaluate them for use under organic farming conditions.

Seed health analysis on seed are made by methods normally used for survey of seed health status in propagation of seeds. The methods are in general slow and depend in some cases on subjective evaluation of the expression of the diseases. Resent studies have shown that huge differences in results exist between the results from different laboratories. To improve the threshold levels, it is necessary with new and more precise methods for seed analysis. Especially in winter cereals in Northern Europe, where the time from harvest to sowing is very short, it is necessary with faster techniques, if the analysis shall be used as a basis for rejection seed lots. The project will develop and implement PCR techniques for seedling blight, glume blotch and leaf stripe, since the PCR technique is quick and unambiguous and the biggest problems are related to the investigation of these diseases.

The development of more correct threshold values based on improved analytical methods will minimise the development of seed borne diseases in organic farming which is relevant especially in the propagation phase, and it will minimise the number of seed lots unnecessarily discarded. To further minimise the development of seed borne diseases and the number of seed lots discarded, control methods will be developed and evaluated. Focus will be put on preventive methods for design of the cropping system which minimise the risk of seed infection, and on seed treatments which immediately apply in organic agriculture and with already existing multipurpose equipment. Focus in seed treatment will be on seed cleaning and seed drying equipment.

The initiatives taken in this project will within the project period of 5 years significantly contribute to development of a sustainable seed production system for organic agriculture. Most knowledge generated in the research can also be used by organic farmers in other countries and in conventional agriculture to reduce the use of seed treatments and other pesticides.

Publications

Project title
VI.1 Healthy seed for organic production of cereals and legumes (ORGSEED)

Project leader
Bent J. Nielsen, senior scientist
Research Centre Flakkebjerg, Department of Crop protection
Danish Institute of Agricultural Sciences (DIAS)

Project participants
Annemarie Fejer Justesen, scientist,
Lars Bødker, senior scientist,
Research Centre Flakkebjerg, Department of Crop protection, DIAS

Erik Fløjgaard Kristensen, scientist,
Research Centre Bygholm, Department of Agricultural Engineering, DIAS

Christiane Scheel, senior plant pathologist, Danish Plant Directorate

Anders Borgen, plant pathologist, Danagro

Ghita Cordsen Nielsen, senior advisor, Danish Agricultural Advisory Centre