STUDIES ON FUSARIUM WILT OF BANANAS: VI. VARIABILITY AND THE CULTIVAR CONCEPT IN FUSARIUM OXYSPORUM f. CUBENSE

Abstract

The range in cultural variability of Fusarium oxysporum f. cubense on potato dextrose agar was studied. Several hundred isolates obtained from diseased varieties of Musa were categorized into four morphological groupings or cultivars. These were termed 'Sporodochial', 'Ropy', 'Cottony Alba', and 'Slimy Pionnotal'. The morphological cultivar 'Sporodochial' was further divided physiologically into 'Odoratum' and 'Inodoratum' cultivars. Clones producing sporodochia were the parental forms from which all other cultural types could arise by mutation. Mutants did not revert to their parental types. A system is proposed for cataloguing clones of plant pathogenic Fusarium species. Based on morphological characters, the catalog is intended to serve as a collection of data which provides also for the categorizing of cultivars.