Eyespot resistance in wheat ×Aegilops kotschyi backcross lines.

In wheat, eyespot caused by Pseudocercosporella herpotrichoides , is one of the main foot-rot diseases. Yield losses up to 40% occur in some years. Plant protection by fungicide application is possible, but a better way is through resistance breeding. Two resistance sources are currently used: Aegilops ventricosa and the old French variety `Cappelle Desprez'. A new source of resistance has been found in the accession AE120 of Ae. kotschyi from the Gatersleben gene bank with the genome constitution UUSvSv. This accession has been crossed and backcrossed twice to susceptible wheat varieties, and in each generation, plants with a relatively high level of resistance have been selected. From this material, lines have been developed and tested in F6 to F8 . Finally, several lines could be classified as moderately resistant, such as the French variety `Cappelle Desprez' after resistance determination during milk ripeness (DC75). No line reached the high resistance level achieved with Pch-1 from Ae. ventricosa . The yield of these lines under infection conditions was higher compared with `Cappelle Desprez'. The line 6018-96-3 showed a high yield of 64.3 dt/ha compared with 59.6 dt/ha, on the average, in combination with the best expression of eyespot resistance in the adult growth stage over 3 years. [ABSTRACT FROM AUTHOR]