RELATIONSHIPS BETWEEN SEED-GERMINATION, FUMONISIN CONTENT, AND FUSARIUM VERTICILLIOIDES INFECTION IN SELECTED MAIZE SAMPLES FROM DIFFERENT REGIONS OF COSTA-RICA

Thirty-five maize seed samples from three geographic regions of Costs Rica were analysed for fumonisin content, germinability, and Fusarium verticillioides infection with and without surface disinfection. The c oncentration of fumonisins in the maize samples varied from 4 ng g(-1) to 16 000 ng g(-1) with an all over-all average of 2500 ng g(-1). The re was a significant difference in fumonisin content between samples f rom Alajuela and Guanacaste. Germination of the seed samples ranged fr om 12% to 98% with significant differences between regions. F. vertici llioides infection was 12-98% and 13-97% for surface-disinfected and n ondisinfected seeds, respectively. There was a significant negative co rrelation (r=-0.52) between fumonisin content and seed germination, bu t no significant correlation was found between fumonisin content and F . verticillioides infection, or between F. verticillioides infection a nd seed germination. Most of the high fumonisin seed samples had some mechanical or insect damage. Whether or not the fumonisins had a direc t effect on germination was not further established. It is concluded t hat the large differences in fumonisin content of maize seeds within a nd between regions are primarily caused by differences in seed quality , genetic diversity of F. verticillioides strains in natural populatio ns, climatic differences between regions, and varietal differences. So me of the fumonisin levels found in this study coincide with levels as sociated with risks to humans and animals in other countries.