DNA POLYMORPHISM AMONG FUSARIUM-OXYSPORUM F-SP ELAEIDIS POPULATIONS FROM OIL PALM, USING A REPEATED AND DISPERSED SEQUENCE PALM

A worldwide collection, of 76 F. oxysporum f.sp. elaeidis isolates (Fo e), and of 21 F. oxysporum isolates from the soil of several palm grov e was analysed by RFLP. As a probe; we used a random DNA fragment (pro be 46) from a genomic library of a Foe isolate. This probe contains tw o different types of sequence, one being repeated and dispersed in the genome ''Palm'', the other being a single-copy sequence. All F. oxysp orum isolates from the palm-grove soils were non-pathogenic to oil pal m. They all had a simple restriction pattern with one band homologous to the single-copy sequence of probe 46. All Foe isolates were pathoge nic to oil palm and they all had complex patterns due to hybridization with ''Palm''. This repetitive sequence reveals that Foe isolates are distinct from the other F. oxysporum palm-grove soils isolates. The s equence can reliably discriminate pathogenic from nonpathogenic oil pa lm isolates, Based on DNA fingerprint similarities, Foe populations we re divided into ten groups consisting of isolates with the same geogra phic origin. Isolates from Brazil and Ecuador were an exception To tha t. rule as they had the same restriction pattern as a few isolates fro m the ivory Coast, suggesting they may originated from Africa.