Occurrence of vascular wilt incidence in fibre crop of flax caused by F. oxysporum sp

Abstract

Flax (Linum usitatissimum L.) is an important bast fibre producing cash crop grown in temperate as well as tropical countries including India. Flax has been introduced as allied fiber crops at CRIJAF, Barrackpore for germplasm evaluation, conservation and varietal development during the year 2009-2010. So far, flax wilt (F. oxysporum f. sp. lini (Schlecht)) was rarely noticed at Research Farm of CRIJAF. But due to continuous monoculture of flax during last five years, localized outbreak of the disease was noticed at research plot during December 2012-January 2013. Three types of wilt symptoms were observed; early wilt averaged up to 90%, late wilt up to 80% and partial wilt up to 10%. Out of seven genotypes, JRF2 was the most susceptible (80%) by JRF-1 (60%) and JRF-3 (40%). However, wilt incidence was least on genotypes viz. JRF-4, FT-850, FT-896 and FT 897. The incidence was drastically increased with the age of the crop and varietal response to moisture as well as to temperature. The pathogen was isolated from the stem section of the infected plant but not from root, pure culture was established and the pathogen was identified as Fusarium oxysporum f. sp. lini. This documentation may play an important role aiming for detail investigation of the disease, breeding/developing resistance varieties and development of disease management strategies under field condition.