AGGRESSIVENESS AND DON PRODUCTION OF FUSARIUM GRAMINEARUM 3ADON AND 15 ADON POPULATIONS AS AFFECTED BY WHEAT CULTIVAR RESISTANCE AND FUNGICIDE TREATMENT, UNDER ND FIELD CONDITIONS, 2009

摘要

Fusarium head blight (FHB) is primarily caused by Fusarium graminearum in North America. The disease affects yield, by reducing harvestable kernel numbers and weight, and affects quality, by contaminating grains with mycotoxins produced by the fungalpathogens. FHB management is mainly through use of wheat cultivars with moderate FHB resistance and through use of fungicides, when warranted. Population studies indicate that F. graminearum isolates can be identified having one of three chemotypes (15 ADON, 3 ADON and NIV) and isolates of 15ADON chemotype were predominant in the population of North America (Ward et al. 2002; Gale et al. 2007). However, several recent studies have shown that the frequency of 3ADON isolates have increased dramatically inrecent years (Burlakoti et al. 2008; Gale et al. 2007; Ward et al. 2008). The newly emerging 3 ADON population appears to be more aggressive than the 15-ADON population based on growth rate, virulence and DON production in culture (Ward et al. 2008). Characterization of the F. graminearum isolates collected from 1980 to 2000 (old collection) and those collected in 2008 (new collection) in North Dakota showed that 3 ADON isolates accounted for only 3% of the old collection, while 45% of the isolates inthe new collection was of 3 ADON chemotype (Puri and Zhong et al., unpublished results). Greenhouse inoculation studies in North Dakota also indicated that most of the 3ADON isolates were more aggressive and produced higher DON than the 15 ADON isolateson susceptible and resistant cultivars (Puri and Zhong et al., unpublished results). However, littleinformation is available on aggressiveness and DON production of F. graminearum 3ADON and 15 ADON populations under field conditions. The objective of this study was to compare the 3-ADON and 15-ADON populations for FHB development and DON production inspring wheat under North Dakota field conditions, as affected by cultivar susceptibility to FHB and as affected by fungicide treatment.