Vegetative compatibility group in Phatogenic isolates of Fusarium oxysporum f.sp. cepae causing twisting disease in Shallot

Issue Date

6-2016

Abstract

Twisting disease caused by Fusarium oxysporum f.sp. cepae, showed the highest disease intensity average of 77.90% in shallot grown in the paddy fields of Nganjuk manifold Vertisol soil, without rotation with rice, during rainy season. The symptoms of twisting disease on shallot caused by Fusarium oxysporum f.sp, cepae in some shallot production centers vary widely. This raises the suspicion that there are differences in virulence caused by VCG differences in pathogen isolates. Thus, the aim of this study was to obtain isolates of Fusarium oxysporum f.sp, cepae from plant materials collected from several shallot production centers and determine if the isolates obtained are from the same VCG group or not. To obtain the isolates of Fusarium oxysporum f.sp. cepae from diseased plant tissue, selective media is used in the isolation method. The Vegetative Compatibility Group (VCG) test of Fusarium oxysporum f.sp. cepae isolates was conducted by pairing nitrate nonutilizing (nit) mutants that are generated on media containing 1.5-4.0% potasium chlorate. There were 8 isolates of Fusarium oxysporum f.sp. cepae taken from the symptomatic cultivar varieties in the central areas of shallot production. It was found that among the 8 isolates of Fusarium oxysporum f.sp. cepae, only 4 of them have different VCG. These four were characterized as the four of different Ras, isolates A, B, C and D and Ras 1, 2, 3 and 4.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

41

Issue

1

Page

36-40

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables, pictures

Language

English

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