Physiological Characterisation of Ascochyta rabiei (Pass.) Lab. Isolated from Diseased Chickpea Fields in Six Regions of Northwestern Algeria

Abstract

The ascochyta blight fungus Ascochyta rabiei (Pass.) Lab. is considered the most damaging pathogen of chickpea (Cicer arietinum L.). Sixteen isolates of the pathogen were collected from six regions in north-western Algeria and were studied for cultural diversity, morphology, pathogenicity and mating type. These isolates showed variation in colony colour as mouse gray, light green, olive green, brown and dark brown, when grown on chickpea seed meal dextrose agar. The produced Conidia had a length ranging from 5.2 to 17.2 μm and a width between 2.4 and 6.7μm. Their number varied from 0.13 x 107/ml to 2.52 x 107/ml. The aggressiveness of isolates was evaluated on 11 chickpea lines. Disease rating on a 1-9 scale indicated a large variability among them and revealed occurrence of the highly aggressive pathotype III in two regions. Both mating types 1-1 and 1-2 were detected. Results from this study show that local strains may overcome resistance in commonly used chickpea cultivars. Some of the described isolates will be useful for breeding Ascochyta blight-resistant chickpea cultivars adapted to geographical regions and for developing necessary control measures.