Création de variétés de froment d’hiver adaptées à la réduction des intrants et répondant aux besoins de l’agriculture durable

Creation of winter wheat varieties suited to reduced input and meeting the needs of sustainable agriculture

Context

In the current context of cereal production and in particular in the wake of the successive falls in winter wheat prices, except for the 2002-2003 season, it now seems essential to manage cereal growing in economic terms, as a function of the gross profit margin generated rather than grain yield. It is hoped that this new approach will limit the drop in cereal growers’ incomes. The winter wheat variety breeding work carried on at CRA?W since 1991 has focussed on developing disease resistance. A further aim is to make varieties more efficient with respect to nitrogen fertilisation, in response to a recent EU priority. The aim of the project is to create winter wheat varieties that are suited to the pedoclimatic conditions of Belgium, Northern France and similar areas and which will also reduce production costs by cutting down on inputs. Such varieties also meet the need for more environmentally-friendly varieties. The development of polygenic resistance to diseases results in more stable varieties over time. This is essential for a sustainable input reduction policy, particularly as regards fungicides. The project thus contributes to the aim of reducing the use of plant protection products.

Objectives

Description of tasks

The breeding work conducted at CRA-W is based on conventional hybridisation techniques. Selection is achieved by evaluating segregating progenies. The breeding scheme uses different methods according to the traits to be selected. The lines or varieties initially identified as potential parents are characterised in low input conditions (no plant protection products and moderate fertilisation). Disease resistance is assessed under artificial inoculation in an experimental design. The bulk population method is used in the younger generations in order to maintain variability, while allowing selection of monogenic traits. Progeny populations are used in F4 as a transition to the pedigree selection carried out in F5, both for stabilizing lines and selecting low heritability traits. The set of traits (resistance, yield, quality, nitrogen efficiency) is looked for in each generation of the whole breeding material. This is thus global selection. Three types of cross are used: single, double and three-way. Bulk population selection is used in the first three years of breeding (F1, F2, F3). The populations are artificially inoculated with brown and yellow rusts (Puccinia striiformis and P. recondita), and wheat glume blotch (Septoria tritici). Artificial inoculation of the ears by wheat Fusarium head blight in F4 is an efficient way to assess resistance to this disease, the mycotoxins of which can cause contamination and have serious consequences. Managing nurseries in suboptimal nitrogen fertilisation conditions enables the most nitrogen-responsive lines to be identified. The lines selected are then tested in comparative yield trials with various nitrogen levels. Pedigree selection is used to fix the lines. Research into breadmaking quality is carried out from the fourth year of breeding, using indirect tests such as the Redman and Zeleny sedimentation test and, at a later stage, the Chopin alveograph. The lines are submitted for the registration tests in F9. Conservation breeding of lines and registered varieties involves creating 80 to 100 families of 10 lines (single-head progenies). The seeds thus produced enable the stability of the line or variety to be guaranteed in propagation.

Expected results

The aim of the winter wheat breeding project is to breed varieties sufficiently resistant to diseases, cold and lodging under low nitrogen fertilisation to maximise the gross profit margin for growers. To fulfil this aim, the lines produced are characterised by high tillering capacity, allowing the sowing density to be reduced. This latter trait is especially significant to enable these varieties to be used within the framework of implementation of agri-environmental measures (AEM), qualifying for a payment of € 100/ha. This type of method generates the best gross profit margin in current market conditions (price < € 90 /tonne), often even without taking account of the AEM payment.

Results obtained

Six varieties of winter wheat have been registered in the Belgian variety catalogue since 2000, marking a revival in breeding at Gembloux. Cactus: registered in the catalogue in 2000. This is characterised by partial resistance to brown rust, as may be seen from the difference in its behaviour between the seedling stage (susceptible) and the adult stage (resistant). This variety has not been distributed. Tourmalin: registered in the catalogue in 2000. This is a semi-late variety. It is characterised by high disease resistance (yellow and brown rust, wheat glume blotch, powdery mildew), and displays excellent behaviour in the presence of wheat Fusarium head blight. This variety offers very good yield potential, particularly under low inputs. It is fairly susceptible to lodging in conditions of high nitrogen fertilisation. Tourmalin has particularly high nitrogen fertilisation efficiency and is also characterised by high straw production. Fourmi: a sister line to Tourmalin, registered in the catalogue in 2001. This is a semi-late variety. Fourmi is a good breadmaking variety (W Chopin 150). It is characterised by a low viscosity value, which makes the variety useful for poultry feed. It has excellent yield potential under low inputs. It is resistant to wheat Fusarium head blight. Straw production from the Fourmi variety is among the highest of all the varieties in the Belgian catalogue. This variety is under European protection. Allié was registered in the catalogue in 2004. This is a moderately early heading and fairly early maturing variety. Allié has a mid-range breadmaking value (W Chopin 170). It is characterised by very high disease resistance, particularly to wheat glume blotch. Allié offers good yield potential under low inputs. The yield, calculated on the basis of two years of official testing, is 101.5% compared to the controls. Piastre was registered in the catalogue in 2005. Piastre has an excellent yield potential (103.5% of the controls) along with a good breadmaking value and a good specific weight. This variety is characterised by very good overall behaviour with respect to the parasite complex. Sombrero was registered in the catalogue in 2005. The Sombrero variety has very good yield potential and is characterised by disease and lodging resistance. Sombrero is a fodder variety.