Screening of onion (Allium cepa L.) germplasm against purple blotch disease

Abstract

Purple blotch disease, caused by Alternaria porri is the most common devastating disease of onion under field conditions throughout the globe. In the present study, 23 genotypes of onion were screened against purple blotch disease where none of the genotypes were found to be immune. Based on the results, the genotypes were grouped into five categories. Five genotypes viz., Akola Safed, Arka Niketan, Punjab Naroya, Arka Lalima, Arka Kirtiman exhibited resistance to this disease. Eight genotypes viz., Bhima Subhra, Arka Bheem, PRO-6, Bhima Raj, Kalyanpur Red Round, L-28, Bhima Dark Red, Bhima Shakti were found to be moderately resistant with 11-20% leaf area infected. A total of ten genotypes were grouped under moderate susceptible category (21-40% leaf area infected). The identified resistant genotypes can further be used for commercial cultivation or may be used as parents in future onion improvement programmes.