Choosing a Winter Soft Wheat Variety Based on Its Management Strategy
1. Presentation
Characterization of the technique
Description of the technique:
A synthesis based on the results of 85 trials, conducted between 2011 and 2015 in the central and western quarter of France, made it possible to define the profile of varieties to be favored a priori according to the risks of diseases and lodging observed in five regions of production with two types of technical itineraries.
The data used to establish this varietal profiling come from the Varieties and Crop Management network, called the "rustic wheats network" established by Inra, Arvalis, the Chambers of Agriculture and the Centers for Initiatives to Promote Agriculture and Rural Environment (CIVAM) of the concerned regions. The technique is described for five major French regions:
- Normandy and North
- Brittany
- Paris Basin and Ile de France
- South Paris Basin and North Burgundy
- Poitou-Charentes and Pays de la Loire
The five years of trials were marked by strong disease pressure (2013 and 2015) or very strong (2012 and 2014), and increasing aggressiveness of yellow rust.
In this network, reasoned management corresponds to the usual regional recommendations to achieve the yield potential of the plot six years out of ten. Integrated management (or low input) combines strategies to reduce the need for plant protection with growth regulators and fungicides (lower seeding density, reduction and delay of nitrogen inputs). The table below shows the main decision rules retained to define these managements with their regional adaptations.
Varieties were chosen a priori to have earliness compatible with the regional climate.
Analysis of the trial network results made it possible, for each region and each itinerary (reasoned or low input), to identify the best performing varieties in terms of yield, within a varietal list of an earliness range adapted to the concerned region. Based on a series of multivariate analyses, the characteristics differentiating the varieties of each varietal performance group were identified.
In almost all regions, the most recent varieties are the best performing, especially under integrated management. Genetic progress includes both an evolution of yield potentials and an improvement of varietal profiles in terms of their adaptation to low input management.
Varietal profiles by technical itinerary for each region
Supported by disease observations made in the network, this work allows proposing a recommendation grid for varietal choice according to technical itineraries (Table 2).
This grid, which only concerns the resistance of varieties to diseases and lodging, can serve as support to choose potentially interesting varieties for a given technical itinerary. In the current state of knowledge, it still needs to be complemented by field evaluation of varietal performance regarding climate hazards and nitrogen feeding paths to better adapt to the nitrogen dose reduction strategy introduced in low input itineraries.
The number of available observations does not allow integrating the resistance profile to take-all.
Implementation period On established crop
It is recommended to anticipate varietal choices before harvest to ensure seed availability.
Spatial scale of implementation Plot
Farm
As soon as the wheat surfaces on the farm are large, it is always recommended to grow several wheat varieties, especially to maintain the durability of varietal resistances by avoiding rapid resistance breakdown by pathogens.
Application of the technique to...
All crops: Not applicable
All soil types: Not applicable
All climatic contexts: Not applicable
Regulation
POSITIVE influence
The use of winter soft wheat varieties fairly resistant to lodging and pests is the subject of a CEPP sheet (action n°29: Reduce the number of treatments by means of winter soft wheat varieties fairly resistant to pests and lodging).
2. Services provided by the technique
Disease management
Genetic resistance to lodging and diseases of varieties is used to respond to the different risk profiles observed for region x technical itinerary pairs.
Disease and lodging risks are mainly determined by climate and regional crop rotations. Choices made at sowing and early in the cycle (seeding density, nitrogen dose) mitigate or accentuate these risks. The proposed varietal range is therefore different depending on whether the farmer opts for a "reasoned" or "integrated" (low input) technical itinerary.
Effect level: MEDIUM if technique used alone, to be combined
Confidence index: HIGH
COMPLEMENTARY TECHNIQUE(S)
INCOMPATIBLE TECHNIQUE(S)
3. Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality: Variable
Effect on water quality: Variable
Effect on fossil resource consumption: Variable
Fossil energy consumption is mainly determined by the mineral nitrogen dose applied.
Other: No effect (neutral)
These criteria depend on the previously chosen technical itinerary. A low input technical itinerary:
- reduces the use of plant protection products: in the trial network, the average IFT goes from 4 to 2.5. It consequently reduces the risks of volatilization of plant protection products.
- reduces nitrogen applied on soft wheat by about thirty units. The gap between nitrogen applied and nitrogen exported is reduced by 13 kg N/ha.
"Agronomic" criteria
Productivity: Increasing
The proposed grid guides towards the most consistently performing varieties for a given technical itinerary (in a given region). It can therefore be stated that making the varietal choice grid available allows each farmer, whatever their strategic choices, to regularize their yields.
Note that integrated itineraries generally show yield decreases of 8% compared to conventional itineraries.
Production quality: No effect (neutral)
"Economic" criteria
Operating costs: Variable
Depends on the previously chosen technical itinerary. Cost differences between itineraries, calculated taking into account the cost of certified seeds and sprayer and spreader passes, vary from €50 to €250/ha.
Mechanization costs: No effect (neutral)
Marginal effect of the choice of technical itinerary on the number of sprayer passes
Margin: Increasing
Thanks to savings made (seeds, nitrogen, plant protection products, number of sprayer passes) and despite yield decreases observed, the semi-net margins of low cost (low input) itineraries are equal or superior to those of conventional itineraries, all varieties combined, when the wheat price is below €145/t. They are lower beyond that.
By choosing, for each itinerary, a variety matching the respective profiles described in table 2 (cf. Presentation of the technique), the performance domain of integrated itineraries expands: the iso-margin threshold between managements rises to €160/t.
"Social" criteria
Working time: Decreasing
Depends on the previously chosen technical itinerary. The reduction of disease and lodging risks allows reducing the number of treatments and the corresponding working time.
Effect on farmer health: Increasing
Exposure to plant protection products depends on the previously chosen technical itinerary. The reduction of disease and lodging risks allows reducing the number of treatments and the applicator's exposure resulting from it.
4. Favored or disadvantaged organisms
Favored Pests
| Organism | Impact of the technique | Type | Details |
|---|
Disadvantaged pests
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| fusarium head blight | pathogen (pest) | Varietal choice is predominant | |
| brown rust | STRONG | pathogen (pest) | Varietal choice is strong. The combination of varietal choice x management accentuates the intensity of the practice |
| yellow rust | STRONG | pathogen (pest) | Varietal choice is predominant |
| septoria tritici blotch | MEDIUM | pathogen (pest) | Combination of varietal choice and management |
Favored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Disadvantaged Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Favored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
Disadvantaged climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|---|---|
| Lodging | STRONG | Management is predominant. Varietal choice reduces the risk in high risk managements (so-called reasoned management) |
5. For further information
- Decision support and varietal selection: a first step towards regionalized wheat profiles
- -Félix I., Rolland B., Omon B., Piaud S., Chevalier B., Lallier S.
Perspectives Agricoles, n°444 pp 40-43, Non-peer-reviewed journal article, 2017
- Comparisons of crop managements: 13 years of multi-criteria results on winter soft wheat
- -Félix I., Rolland B., Omon B., Piaud S., Chevalier B., Lallier S.
RMT Innovative crops systems, 2016
- ITK Network – rustic wheat and barley
- -Piaud S., Omon B., Chevalier B., Guérin O., Lallier S., Félix I., Rolland B.
RMT Innovative cropping systems, 2016
6. Keywords
Pest control method: Genetic control
Mode of action: Mitigation
Type of strategy regarding pesticide use: Redesign
Annexes
Contribue à
S'applique aux cultures suivantes
Défavorise les bioagresseurs suivants
Défavorise les accidents climatiques
