SURVEY OF FUSARIUM SPECIES IN AN ARID ENVIRONMENT OF BAHRAIN .4. PREVALENCE OF FUSARIUM SPECIES IN VARIOUS SOIL GROUPS USING SEVERAL ISOLATION TECHNIQUES

Three isolation techniques, namely soil dilution, soil plating and soi l baiting were used to recover six Fusarium species from various soil groups in the arid environment of Bahrain. A total of 428 isolates wer e recovered using the above techniques. Soil samples analyzed were gen erally poor in organic matter, slightly alkaline, highly saline and lo w in total soluble salts. Maximum isolate recovery and species spectru m were mainly recorded from soils of regosols, characterized by low sa linity levels (660 mu S cm(-1)). Of species encountered, Fusarium sola ni, F. equiseti and F. compactum were dominant and frequent in all soi l groups. Species prevalence, distribution and total isolate s were gr eatly influenced by soil salinity, which counteracted other soil param eters. The soil dilution plate yielded the highest population level an d species diversity from regosol soils. Significant interaction occurr ed between the applied technique and species recovery, as determined b y chi-square analysis. Results obtained are in favour of the use of mu lti-isolation techniques and media approach for comparing survey studi es of soil-borne Fusarin from noncultivated desert environment.