Breeding faba bean for resistance to Ascochyta blight

Abstract

Ascochyta blight (Didymella fabae Jellis and Punithalingam) is one of the most important foliar diseases that affect the quality and seed yield of faba bean (Vicia faba L.) worldwide. Breeding for resistance to Ascochyta blight is a major objective in many faba bean breeding programs. At ICARDA, systematic screening of germplasm accessions and elite breeding lines for resistance to Ascochyta blight is carried out at Tel Hadya Aleppo and Lattakia under artificial field inoculation with mixtures of aggressive isolates of the pathogen, since 1977. This has resulted in the identification of 120 resistance sources with origins mainly from Ecuador, Egypt, Ethiopia, Canada China, Greece, Italy, Lebanon, Morocco, Peru, Spain, Syria and Tunisia. The resistance sources were inter-crossed with landraces adapted to diverse environments. More than 2000 breeding lines (F4 to F7 generations) emanating from the crosses involving resistant donors with landraces are screened for their reaction to Ascochyta blight on yearly basis. Only the identified resistant lines in advanced generations are tested under natural infestation in different locations under platform of international nurseries. From 2008 to 2011, 65 lines were tested in different locations in North Africa and west Asia. 28 lines maintained their resistance to ascochyta blight in all locations.