Vol. 10, Issue 6 (2021)

Author(s):
Padma Angadi, Aswathanarayana DS, Amaresh YS, Ramesh G, Savitha AS and Ajithkumar K

Abstract:
Onion (Allium cepa L.), rightly called as “queen of kitchen” is being cultivated extensively throughout the country under a wide range of climatic conditions. Onion purple blotch is the major disease caused by Alternaria porri (Ellis) Cif., causing economic yield loss. The pathogen meant to produce several toxic metabolites both in culture media and in the infected tissues, which were involved in the pathogenesis and symptom expressions. The toxin was extracted from the pure culture of A. porri in in-vitro The Liquid Chromatography Mass Spectrometry (LCMS) studies on detection of toxin produced from Alternaria porri, indicated the presence of tentoxin. The toxin was used for bioassay at various concentrations (50 to 2000 ppm) on seedlings of Arka Kalyan and Bellary Red and the results revelead the significant toxicity on the host tested. Toxin concentration at 2000 ppm inhibited the seed germination of 86.79 and 65.13 per cent in Bellary Red and Arka Kalyan, respectively and shoot and root inhibition of 26.67 and 52.98 per cent in Bellary Red and 28.15 and 42.19 per cent in Arka Kalyan, respectively. Foliar spray of toxin showed maximum Per cent disease index of 50.67 and 42.00 per cent in Bellary Red and Arka Kalyan, respectively at 2000 ppm toxin concentration.