Characteristics of spring barley varieties for organic farming

Modern spring barley varieties have been developed with the aim of combining high productivity and standardised product quality under high-input conditions using pesticides for control of weeds, diseases and insects as well as heavy application of nutrient-rich and water-soluble inorganic fertilizers. The organic growing system, as defined by EU-directive 2092/91, is a system where pesticides and artificial fertilizers are generally not allowed. Hence, biotic and abiotic stresses have to be overcome by growing the appropriate varieties and by practicing good farm management. The important spring barley traits to be considered in organic farming are related to the inherited viability and adaptation of plants to survive biotic and abiotic stresses and includes competitive ability (morphology, weed tolerance, growth rate, allelopathy), disease resistance (morphology, specific and non-specific resistance proporties, disease tolerance) and nutrient acquisition ability (root morphology, nutrient uptake and use efficiencies, low-nutrient tolerance, symbioses). An important question is whether modern spring barley varieties possess the right combinations of these characteristics to ensure a stable and acceptable yield of good quality when grown under different organic growing conditions. We know that varieties often perform and yield differently in different environments due to genotype-environment interactions, so it may be important to evaluate characteristics of varieties in organic as well as in conventional farming systems. However, it remains unclear to date whether the differences between the conventional and the organic growing systems are large enough to justify breeding and testing of varieties in both environments. Extensive field experiments and refined statistical methods are needed to clarify this. Characterisation of varieties as part of the official variety testing is at present done under conventional farming conditions in Denmark.

In contrast to the conventional farming systems, the variation between different organic growing systems is very large. In some organic crop rotations with weed problems, a highly competitive variety is the most suitable while this variety might not be very useful if used with undersown crops. In situations with high soil fertility, e.g. after grass-clover leys, a high yielding variety with certain disease resistance genes would be the most optimal while in situations with low fertility a variety with high nutrient uptake or use efficiencies would be preferred and susceptibility to diseases may not be a great problem. Further, at some locations and years one type of disease may be prevailing requiring specific resistance genes or morphology of the plant, in other cases other disease complexes demand another type of plant phenotype. Therefore, it is not possible to obtain a single best variety for organic farming in general and in many cases the best choice might be to grow a mixture of varieties, which combines many desirable characteristics. Using mixtures of appropriate varieties in organic farming might, therefore, be a way of obtaining stable and acceptable yields. Variety mixtures have so far been studied especially in relation to effect of single diseases and under conventional farming conditions. Experimental as well as modelling studies are needed to investigate whether these results can be transferred to the organic farming systems, where complicated interactions between crop, weeds and diseases under the influence of nutrient availability exist. The potential use of variety mixtures adapted to local growing conditions ("farm varieties") needs also to be studied in more details. For choosing the appropriate varieties for variety mixtures, it is important to have detailed information on the characteristics of the varieties available.

In the near future, modern breeding might produce an increasingly number of varieties using artificial genetical modifications (GMOs). Genetically modified crops are not allowed according to organic principles as defined by the International Federation of Organic Agriculture Movement (IFOAM). Breeding related to organic farming may, however, take advantage of modern biotechnology by using DNA-markers to enhance the breeding process. More such markers for traits of importance to organic farming are needed.

In conclusion, the aims of this project are to provide experimental data, statistical analyses and modelling to fulfil the objectives mentioned under item 8. This work is organised into 6 scientific Work Packages focusing on:

Variety testing (WP1), Crop-weed interactions (WP2), Disease complexes (WP3), Nutrient acquistition and crop performance (WP4), Genetic markers (WP5) and Data analysis and modelling (WP6).

The project takes advantage of the unique growing facilities in the organic workshop areas in Flakkebjerg, Jyndevad og Foulum, where variety trials with about 120 modern varieties, lines and variety mixtures as well as detailed field trials investigating specific environmental factors will be conducted. Corresponding trials will to some extend take place under conventional growing conditions. A strong management accomplishes the interaction and coordination between the different Work Packages and discussions and plannings for shared plant material, experimental designs and data analyses will take place regularily. Project results will to a large extent be available on the internet as supplement to scientific publications.

Main objectives:

• Identify combinations of plant characteristics required for a barley crop to be successful in organic growing systems and develop methodologies for measuring these characteristics.
• Evaluate, by investigating genotype-environment interactions, the need for specific variety trials for organic farming, and if necessary implement such trials.
• Improve yield and yield stability in different organic farming systems by strategic use of the appropriate varieties and variety mixtures.
• Investigate the potential of different variety mixtures for reducing diseases and weeds and increasing nutrient uptake efficiency.
• Obtain new knowledge on plant competition, disease complexes, epidemiological models, nutrient acquisition and associations between molecular markers and agronomical traits.

Publications

Project title
VI.2 Characteristics of spring barley varieties for organic farming (BAR_OF)


Project participants

Department of Plant Research, Risø National Laboratory
Senior research specialist Hanne Østergård, (Head of Project)
Scientist Gunter Backes
PhD student Jeanette Vollmer

Department of Variety testing, DIAS
Head of Department Gerhard Deneken,
Scientist Jacob Willas

Department of Crop Protection - Weed Ecology, DIAS
Scientist Preben Klarskov Hansen ,
Scientist Ilse Ankjær Rasmussen

Department of Crop Protection - Plant Pathology, DIAS
Senior scientist Hans Pinnschmidt
Senior scientist Mogens Hovmøller,

Department of Crop Physiology and Soil Science, DIAS
Senior scientist Jørgen E. Olesen
Scientist Jørgen Berntsen
Scientist Ingrid K. Thomsen

Department of Agricultural Systems, DIAS
Senior scientist Kristian Kristensen

Department of Plant Biology, KVL
Associate professor Lisa Munk,

Department of Agricultural Sciences, KVL
Professor Niels Erik Nielsen