Sowing / transplanting mixtures of varieties of the same species
1. Presentation
Characterization of the technique
Description of the technique:
| Jacques Girard | Chambre d'agriculture of Calvados | j.girard(at)calvados.chambagri.fr | Caen (14) |
|---|---|---|---|
| Julien Halska | INRA | julien.halska(at)grignon.inra.fr | Dijon (21) |
| Jean-Michel Hillaireau | INRA | jean-michel.hillaireau(at)stlaurent.lusignan.inra.fr | Saint Laurent de la Prée (17) |
| Lionel Jouy | Arvalis plant institute | L.JOUY(at)arvalisinstitutduvegetal.fr | Boigneville (91) |
| Sébastien Minette | Regional Chamber of Agriculture Poitou-Charentes | Sebastien.MINETTE(at)poitou-charentes.chambagri.fr | Lusignan (86) |
| Patrick Saulas | INRA | patrick.saulas(at)grignon.inra.fr | Grignon (78) |
| Muriel Valentin-Morison | INRA | Muriel.Morison(at)grignon.inra.fr | Grignon (78) |
Spam protection: To use these addresses, replace (at) with @
Cereals: mainly to reduce fungicide use, an intraplot genetic diversity is created by associating several varieties (3 to 4 preferably, in equal parts or not, or possibly proportional to the TGW) having complementary resistances to diseases. In this mixture, the susceptibility of one variety to a disease is compensated by a higher resistance of the other varieties to that disease. The choice of varieties is also based on earliness, height, ... to be able to harvest the mixture under good conditions. Seeds of the different varieties must be mixed before sowing. Rapeseed: to limit damage caused by pollen beetles, it is possible to sow in mixture or border, 4 to 10% of an earlier variety (or of navette)
Example of implementation: Examples of varietal associations tested in organic farming by the Chambers of Agriculture of Pays de la Loire (and compared to the same varieties in pure culture): Attlass / Renan / Saturnus or Caphorn / Renan / Attlass. Another example from an INRA experiment aiming to reduce fungicide treatments, especially against rust brown and septoria: a binary association, Soissons + Delfi, and a ternary association, Soissons + Delfi + Pactole. (For more information on these examples, see in the bibliography Varietal associations and fungicide interventions against septoria and brown rust of winter wheat and Mixing cereal varieties to enhance the qualities of each, 9 years of trials.)
Details on the technique:
General observations:
Different trials: 1. Long-term trial of La Cage "sustainable and integrated cropping system" (INRA Grignon). 2. "Rustic Wheat" network (Arvalis - INRA - CA) => summaries available from these organizations.
Implementation period On established crop
But the mixture can be designed to best resist expected diseases depending on the previous crop, for example favoring resistance to fusarium if the previous crop was maize.
Spatial scale of implementation Plot
Application of the technique to...
All crops: Sometimes difficult to generalize
'Lack of reference for many arable crops species, mainly tested for soft wheat. Varieties evolve very rapidly, making it difficult to retain sufficiently generic criteria to design varietal mixtures.'
Soft wheat winter: Association criteria: 1) same market outlet 2) synchronous cycles (no earliness differences) 3) same stem height 4) high proportion of resistant varieties and complementary resistances to different diseases.
Barley winter - Barley spring: practiced abroad. Association criteria little or not studied, but likely close to those of soft wheat.
Oat winter - Oat spring - Durum wheat winter - Durum wheat spring - spring soft wheat - Einkorn, Emmer - Spelt - Rye winter - Rye spring - Triticale winter - Triticale spring: association criteria little or not studied, but likely close to those of soft wheat.
Rice: practiced in China
Potato: In a given territory, late blight epidemics progress more slowly if sensitive and resistant varieties are associated in the same plots rather than grown separately (according to simulations).
All soil types: Easily generalizable
All climatic contexts: Easily generalizable
The reduction of disease impact depends on the climatic year => the stronger the disease pressure, the more interesting the mixture and the more it values differences in sensitivity between varieties
Regulation
POSITIVE influence
The use of mixtures of varieties, resistant to pathogens in wheat or with varied flowering dates in rapeseed, is the subject of CEPP sheets:
- Action n°11: Avoid insecticide treatment against pollen beetles by associating a very early flowering rapeseed variety with the main variety
- Action n°49: Reduce treatments by means of mixtures of fairly resistant soft wheat varieties
2. Services provided by the technique
3. Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality: Variable
Phytosanitary emissions: DECREASE
GHG emissions: VARIABLE
Effect on water quality: Increasing
Pesticides: DECREASE
Effect on fossil resource consumption: Decreasing
Fossil energy consumption: DECREASE
Phosphorus consumption: DECREASE
Other: No effect (neutral)
Pollutant transfer to water (N, P, phyto ...): 'variable
Reduction in fungicide and insecticide use, but molecules rarely found in waters.
Pollutant transfer to air (N, P, phyto ...): Decrease
Reduction in fungicide use.
Fossil energy consumption: Decrease
Reduction in number of passes.
GHG emissions: no knowledge on impact
Reduction of CO2 emissions by reducing number of passes. No effect on N2O.
"Agronomic" criteria
Productivity: Increasing
Effect on cropping system productivity: not applicable Cereals: yield of the mixture generally increased compared to the average of the pure varieties composing the mixture. E.g. for soft wheat: increase of 3% (thesis M. Belhag). Yields are also more stable for varietal associations, including under suboptimal conditions (water or nitrogen stress for example).
Soil fertility: No knowledge on impact
Water stress: No effect (neutral)
Functional Biodiversity: Increasing
Increase in intra-plot diversity, even if the species is identical.
Other agronomic criteria: Variable
Use of inputs: Decrease
- Varietal mixtures are commonly used in low-input systems, combined with other agronomic levers (sowing date, sowing density, no growth regulator, reduced fungicide insecticide, nitrogen) ; they help reduce input use. Nitrogen needs may vary depending on varieties.
Durability of varietal resistances: Increase
Varietal associations help preserve varietal resistances. It is important to associate varieties with different resistances and to vary varieties from year to year.
Pest resistance to insecticides: Decrease
In the case of rapeseed, lower insecticide pressure on pollen beetles can reduce resistance development (to pyrethroids).
"Economic" criteria
Operating costs: Decreasing
Fungicide and other costs if managed in an integrated system. Insecticide costs.
Mechanization costs: Decreasing
Reduction in number of mechanical passes (e.g. 1 sprayer pass on soft wheat).
Margin: Increasing
Variable depending on the climatic conditions of the year and crop selling prices, but the mixture leads to a reduction in phytosanitary costs and maintenance or improvement of yield. Hence an increase in crop margins.
Other economic criteria: Variable
Fuel consumption: Decrease
Reduction in number of mechanical passes (e.g. 1 sprayer pass on soft wheat).
Market outlets: Variable
Varietal mixtures are not currently well accepted by storage organizations due to mixture composition at harvest and traceability. They can sometimes be downgraded. However, some trials conducted with superior bread-making soft wheat varieties have achieved baking scores equivalent to those of monovarietal crops. For rapeseed, this does not seem to be a problem.
"Social" criteria
Working time: Decreasing
Slight decrease due to fewer mechanical passes (e.g. 1 sprayer pass on soft wheat).
Peak period: Decreasing
Slight decrease due to fewer mechanical passes (e.g. 1 sprayer pass on soft wheat).
Effect on farmer health: Increasing
Risks for applicator related to pesticide use: Decrease
Reduced risk of pesticide exposure for applicators.
Observation time: Variable
Diseases being delayed and slowed, the risk of a "major fungal accident" is significantly reduced. This leads to a reduced "need for monitoring" and may allow a lighter fungicide program triggered at a well-chosen stage.
4. Organisms favored or disfavored
Favored Bioagressors
| Organism | Impact of the technique | Type | Details |
|---|
Disfavored bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| late blight | MEDIUM | pathogen (bioagressor) | In a given territory, epidemics progress more slowly if sensitive and resistant varieties are associated in the same plots rather than grown separately (according to simulations). |
| pollen beetle | LOW | pest, predator or parasite | |
| cereal powdery mildew | MEDIUM | pathogen (bioagressor) | |
| take-all | MEDIUM | pathogen (bioagressor) | |
| rhynchosporium | MEDIUM | pathogen (bioagressor) | |
| brown rust | MEDIUM | pathogen (bioagressor) | |
| yellow rust | MEDIUM | pathogen (bioagressor) | |
| barley leaf rust | MEDIUM | pathogen (bioagressor) | |
| septoria leaf blotch | MEDIUM | pathogen (bioagressor) |
Favored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Disfavored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Favored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
Disfavored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
5. For further information
- Assessment of bread wheat cultivar mixtures feasibility and stability in on-farm conditions: application to crop production in northern France
- -Belhaj Makram (INRA)
Peer-reviewed journal article, 2003
- Varietal associations: how to create field diversity?
- -Thomas F. (INRA); Saulas P. (INRA); de Vallavieille-Pope C. (INRA)
TCS n°50, Press article, 2008
- Varietal associations and fungicide interventions against septoria and rust brown of winter wheat
- -Mille Bruno (INRA); De Valavieille-pope Claude (INRA)
Cahiers Agricultures. Volume 10, Number 2, 125-9, March - April 2001, Research notes, Peer-reviewed article, 2001
- Evaluation of the stability and feasibility of wheat varietal associations
- -Belhaj Makram (INRA)
INRA, University works
Thesis
- Manage straw positively, secure structure and change previous crop
- -Mille Bruno (INRA); De Valavieille-pope Claude (INRA)
Cahiers Agricultures. Volume 10, Number 2, 125-9, March - April 2001, Research notes, Press article, 2001
- Invasion of Phytophthora infestans at the landscape level: how do spatial and weather modulate the consequences of spatial heterogeneity in host resistance?
- -Skelsey P.; Rossing W. A. H.; Kessel G. J. T.; Van der Werf W. (Wageningen university)
Ecology and epidemiology volume 100, N° 11, pp 1146-1161, Peer-reviewed article, 2010
- Screening and mixing varieties to reduce pesticide use - case of cereal straw
- -Innocent Pambou (CA 49)
Agro-phytos day 2018, Thursday 4 February 2010, La Pommeraye, Multimedia, 2010
- Varietal associations: increase biodiversity to better control diseases
- -de Vallavieille-Pope Claude (INRA); Belhaj Makram (INRA), Mille Bruno (INRA); Meynard Jean-Marc (INRA)
INRA Environment file n° 30, Peer-reviewed article, 2006
- Wheat varietal associations: performance and disease control
- -Jeuffroy M. H. (INRA); Meynard J. M. (INRA); de Valavieille-Pope C. (INRA); Belhaj Fraj M. (National Agronomic Institute of Tunisia); Saulas P. (INRA)
French Breeder, 61, 75-84; French Breeders Association Days, February 2010, Conference proceedings, 2010
- Mixing cereal varieties to enhance the qualities of each, 9 years of trials
- -Maurice Renan (Chamber of Agriculture of Pays de la Loire)
Organic network of Chambers of Agriculture of Pays de la Loire, Technical brochure, 2011
- Varietal mixtures of wheats or barleys: theory, practice and examples
- -Wolf S. M. (Wakelyns Agroforestry); De Valavieille-pope C. (INRA); Lannou C. (INRA); Goyeau H. (INRA); Finckh M. R. (Institute of Plant Sciences, Swiss Federal Institute of Technology); Munk L. (Royal Veterinary and Agricultural University); Merz U. (Institute of Plant Sciences, Swiss Federal Institute of Technology); Valenghi D. (FAL Reckenholz); Gacek E. COBORU Research Centre for Cultivar Testing
Phytoma Plant Protection, n°497, pp 28-31, Press article, 1997
6. Keywords
Bioagressor control method: Genetic control
Mode of action: Attenuation
Type of strategy regarding pesticide use: Substitution
Annexes
S'applique aux cultures suivantes
Défavorise les bioagresseurs suivants
