Vol. 11, Special Issue 8 (2022)

Author(s):
Muthukumar G, Udhayakumar R, Muthukumar A, Muthukumaran N and Ayyandurai M

Abstract:
Onion (Allium cepa L. var. aggregatum Don.) is the world's most important commercial vegetable crop. Fusarium basal rot (FBR) is an economically significant onion disease that causes yield losses of up to 50 per cent in the field and 30 to 40 per cent during post-harvest storage of bulbs. Survey was conducted in onion growing areas of Tiruchirappalli, Perambalur, Salem, Karur and Madurai districts of Tamil Nadu during 2021-2022 and collected the infected diseased samples, from this ten isolates of Fusarium were isolated under in-vitro. FOC pathogens multiplied with different substrates, among them sand maize medium is a best source for production of inoculum of pathogens. During the pathogenicity among the ten isolates, FOC₆ isolated from Thogaimalai village was identified as a virulent isolate which recorded 56% disease incidence. The isolates were confirmed by both morphological and cultural characters. The conidial and resting structure also seen under SEM Molecular confirmation was done by using fungal universal primer ITS1 and ITS4 and we obtained approximately 550-600 bp common fragments in FOC₆ isolate of Fusarium. Different solid media was used for evaluate the growth of the FOC isolates, among them potato dextrose agar medium shows vigorous mycelial growth under in vitro condition.