3.4.42
BREEDING WHEAT FOR RESISTANCE TO FUSARIUM HEAD BLIGHT AND LEAF DISEASES WITH SPECIAL REFERENCE TO TOXIN CONTAMINATION

A MESTERHAZY and T BARTOK

Cereal Research Institute, Szeged, Hungary

Background and objectives
Fusarium head blight (FHB) resistance is one of the most important goals of recent breeding in wheat, as devastating epidemics have focused attention on the problem. However, FHB resistance alone does not help when plants are also susceptible to leaf diseases. Therefore our aim 28 years ago was to develop new lines with high levels of resistance against FHB, powdery mildew, stem rust and leaf rust. In the past we have evaluated methods for resistance testing and breeding.

Materials and methods
As resistance sources, Sumey-3, Nobeoka Bozu and Ringo Star were used and crossed with genotypes having resistance to leaf diseases. For stem rust resistance Sr36 was applied, originating from Arthur 71 (Mini Mano), and Sr31 from SAgvAri. Mini Mano had an excellent powdery mildew resistance with unknown gene(s). Resistance was controlled by artificial inoculation for FHB, leaf rust and stem rust. Powdery mildew ratings based on natural epidemics were present every year. For scientific and methodical background, see [1, 2].

Results and conclusions
Some of the progenies had the same level of resistance as the resistance sources against FHB on a much better agronomic form. The many years of testing showed that DON contamination was in these lines 0 or very low compared with the susceptible cultivars. In these the FHB susceptibility was very high, scabby grains reaching 90%. DON contamination rose up to 100 ppm or higher. Even the most aggressive isolates of F. graminearum or F. culmorum did not cause disease, or its extent was very low. In some lines we found a high level of resistance to all the other diseases. In some cases also the baking quality was good or excellent. As they did not reach the control cultivars in yielding ability, they can serve as crossing partners for commercial breeding.

The FHB resistance of spring wheat resistance sources has been incorporated into winter wheat. We have resistance in these lines also against DON contamination. This could be combined with the resistance to powdery mildew, stem rust and leaf rust. These lines serve as outstanding breeding material for commercial breeding.

The authors thank for financial support OTKA (grant No. 585) and OMFB (grant No. 6315).

References
1. Mesterhazy A, 1995. Plant Breeding 114, 377-386.
2. Mesterhazy A, 1997. Cereal Res. Comm. 25, 631-637.