Variation in leaf infection of winter wheat cultivars by fungi of genus Septoria in relation to environmental conditions

Abstract

The study, covering analysis of the variation in the intensity of septoria leaf spot, made use of the results obtained in Post-registration Variety Testing experiments carried out in Lower Silesia. Of these experiments, eight locations characterized by diverse soil conditions were selected. The analysis regarded a three-year period of cultivation, spanning 2004–2006, of eleven winter wheat cultivars. The experiments were conducted in the standard variant (a 1 ) and the intensive (a 2 ), the latter differing in nitrogen fertilization higher by 40 kg ha–1, full chemical protection against fungal diseases, use of a growth regulator and foliar feeding of the plants with multi-nutrient preparation. The analysis performed has revealed significant interaction of the cultivars with the environment, which points out to varied reaction of the wheat genotypes to atmospheric and edaphic conditions in particular years of the study. The high values of the genotype-environment interaction obtained for the locations of Kobierzyce, Tarnow, Pawlowice and Krościna indicate that in the area of Lower Silesia these experimental sites are distinguishable by increased danger that the plants may be highly infected by populations of fungi representing the genus Septoria. The fact that the number of cultivars analyzed in Post-registration Variety Testing trials each year is different, the evaluations of the interaction between the genotypes and the environments may not be absolutely reliable. Therefore, the number of experimental sites of variable edaphic-climatic conditions which is taken under analysis should be large enough. The significant differences in the level of infection of particular genotypes obtained for some locations indicate the necessity to evaluate of new cultivars in numerous environments considering the genotype-environment interaction and the danger of occurrence of new races of fungi characterized by increased aggressiveness.