THE USE OF THE AREA UNDER THE DISEASE PROGRESS CURVE (AUDPC) TO ASSESS THE EPIDEMICS OF SEPTORIA TRITICI IN WINTER WHEAT PUBLISHEDMirela PARASCHIVU, Otilia COTUNA, M. PARASCHIVU
Septoria tritici blotch (STB) caused by the ascomycete fungus Mycosphaerella graminicola(anamorph S. tritici) is currently one of the most serious foliar disease of wheat in Europe and otherworld regions characterized by temperate and wet environment during growing season. Twenty-fivewheat genotypes with different resistance levels were evaluated in natural conditions for their reaction toS. tritici attack during 2009-2010 year. The experimental design was a randomized block design withthree replications. Disease rating was visually recorded by using the double-digit scale (00-99) in twodifferent times and crop stages (Z53-1/4 head out and Z70-milk development). There were also calculatedthe Septoria Progress Coefficient (SPC) and Area under Disease Progress Curve (AUDPC) for eachwheat genotype evaluated. SPC was low for the higher genotypes comparatively with the shortest onesleading to the conclusion that disease progress is higher as plant height is low (r=-0,8584***). The sameaspect was also emphasized by the negative correlation between plants height and disease progressheight (r=-0,7241**).The shortest genotypes showed higher necrosis percentage and AUDPC values.There was also a correspondence between genotype susceptibility and AUDPC showing that the mostsusceptible wheat cultivars recorded higher AUDPC values. Thus, Renan (295), Esential (231),Renesansa (234), Autan (186) recorded the highest AUDPC values while Aztec (45), Meunier (41) andCapo (20) had the best resistance reaction to S. tritici attack. Comparatively with the control Brianacultivar (AUDPC = 153), created to ARDS Simnic, the differences recorded by Renan, RenesansaEsential, Ciprian, Exotic, Cezanne, Aztec, Capo and Meunier were statistically significant. There wasalso a negative correlation between AUDPC and yield (r=-0,5140). The Area under the Disease ProgressCurve (AUDPC) can be an efficient instrument to evaluate the epidemic development of foliar pathogenS. tritici considering each genotype susceptibility and specific architecture.
AUDPC, disease, SPC, S.tritici blotch, wheat