Resistance of European winter wheat cultivars to spot blotch at juvenile growth stages

A total of 99 modern European winter wheat cultivars and breeding lines were studied for resistance to four Bipolaris sorokiniana isolates, obtained from wheat straw and grain, under laboratory conditions using a detached leaf technique. The resistance was evaluated on a 0 to 100% scale, where the lowest percent represents the highest resistance. Four checks with known resistance levels were employed as references. The screening technique used revealed low resistance of the tested material when compared for percent of disease severity (DS), but considerably higher variability of resistance when compared for area under the disease progress curve (AUDPC) index. The accessions showed the AUDPC index to vary from 0.11-0.84, 0.11-0.75, 0.10-0.84, and 0.09-0.68, respectively, for the four isolates. The correlation between DS and AUDPC index was strong (r = 0.82-0.92, P