Screening Techniques for Ascochyta Blight of Chickpea

Abstract

Blight caused by Ascochyta rabiei (Pass.) Lab. is the major disease of chickpea in North Africa, West Asia, and South and East Europe. The use of resistant cultivars is considered to be the best way of controlling the disease. Though considerable work has been done on the development of screening techniques, rating scales, and other related aspects, simple and reliable techniques for large-scale field screening were not available. The earlier methods of inoculation for field screening consisted of spraying with a pycnidiospore suspension from the pure culture of the fungus and covering the plants with "Sarkanda" screens or cloth tents, or spreading the diseased chickpea debris, or dried culture of the fungus over the plants, or mixing the diseased plant debris with the seed at the time of sowing and depending on natural rainfall for disease development (Luthra et at 1938; Grewal and Vir 1974; Bedi 1949). These methods were not adequate for large-scale field screening of germplasm lines and breeding materials. Similarly, greenhouse or pot culture screening techniques for large-scale screening were not available. The lack of reliable field-screening techniques for large-scale screening of germplasm lines and breeding materials hampered the progress of resistance breeding. A need for further standardization of both field and laboratory screening techniques as well as rating scales was felt. The results of the field and greenhouse screening techniques and the rating scales standardized for evaluating the materials are presented in this paper.