COMPARISON OF VISUAL HEAD BLIGHT RATINGS, SEED INFECTION LEVELS, AND DEOXYNIVALENOL PRODUCTION FOR ASSESSMENT OF RESISTANCE IN CEREALS INOCULATED WITH FUSARIUM-CULMORUM

Seven spring wheat, 13 barley, 14 oats and 20 winter wheat genotypes w ere inoculated at flowering in 1993 and 1994 with mixed conidial suspe nsions of 8 isolates of Fusarium culmorum. Four weeks after inoculatio n, head blight was recorded in the field. After harvest, seed infectio n was assessed by a Freezing Blotter Test in the laboratory. Seed samp les were also analyzed for deoxynivalenol (DON) content. Differences w ere found in head blight rating, the levels of infected seeds and the DON content between wheat, barley, and oats and between cultivars. Hig hly significant correlations were found between the percentage of heav ily infected seed and the DON content. The weighted mean value of infe cted seeds and DON content were also significantly correlated. No sign ificant correlation was found between head blight rating in the field and DON content. The level of infected seeds, as determined by the Fre ezing Blotter Test, was a better indication of the DON content in the seeds than the head blight rating. This visual assessment of levels of infected seeds gives a reliable estimate of resistance to Fusarium.