EFFECT OF CULTIVAR AND STRAIN INTERACTIONS IN THE SCREENING OF RESISTANCE AGAINST WHEAT SCAB CAUSED BY FUSARIUM-GRAMINEARUM

Factorial experiments were carried out in the field at the campus of U niversite Laval in 1991 and 1992, and Saint-Louis-de-Pintendre station in 1992 and 1993. The objective was to specify if wheat scab developm ent caused by Fusarium graminearum is significantly affected by cultiv ar x strain interactions. Eleven wheat (Triticum aestivum) cultivars a nd one triticale (x Triticosecale) cultivar representing the range of sensitivity to this disease in Quebec were inoculated with nine strain s of F. graminearum, Significant interactions between cultivars, strai ns and environments were shown by the results of a combined analysis o f variance. Cultivar x strain and cultivar x environment interactions explained a small proportion of the total sum of squares and did not h ave a strong impact on cultivar average ranking by environment or stra in. However, the examination of cultivar x strain interactions reveale d that the rank of cultivars such as Casavant and Concorde changed whe n different strains were compared. This research shows for the first t ime that all interactions involving cultivars, strains and environment s have a similar impact on wheat scab resistance screening.