One obvious symptom caused by Fusarium moniliforme is spindly growth of plant seedlings, which results from the secretion of gibberellic acid (GA 3) from the fungus. It is well known that rice lines carrying the semidwarf allele sd1 are sensitive to GA 3 at the
seedling and tillering stages (Kumar, 1984; Li et al.,2005), and this allele is present in most of the modern indica rice varieties, hybrid rice as well as half of the japonica varieties (Zhu and Li, 1984). Nonetheless, more than 60 dwarf genes and 12 semidwarf genes that are non-allelic to sd1 have been reported (Kinoshita,1995); some of which are insensitive to GA3. These germplasms may provide a valuable resource for the screening of materials showing resistance to bakanae disease. However, whether rice materials with different
dwarf or semidwarf genes are resistant to bakanae is unknown.