Influence of Septoria tritici on Yield, Yield Components, and Test Weight of Wheat under Two Nitrogen Fertilization Conditions

Abstract

tion of the influence of N supply on the disease severity have been studied with contrasting results (Johnston et Nitrogen fertilization is required for achieving high yields in wheat al., 1979;Howard et al., 1994; Leitch and Jenkins, 1995; (Triticum aestivum L.), but N may enhance the development of leaf Lovell and Royle, 1999). Simó n et al. (1998) found that blotch (Septoria tritici Roberge in Desmaz., teleomorph Mycosphaerella graminicola (Fuckel) J. Schrö t. in Cohn). The present study in conducive conditions, N fertilization increases the was undertaken to investigate how Septoria leaf blotch affects yield, severity of Septoria leaf blotch and discussed the effect yield components, and test weight (TW) of different cultivars under of different factors affecting the influence of N supply. different N supplies. Field experiments with six cultivars were carried Most of previous papers studying the influence of N out in a split-split plot design during 1996 and 1997. Inoculation treaton the expression of disease concerned the expansion ments were the main plots, N fertilization levels were the subplots, of the necrotic area or pycnidial coverage on foliage. and cultivars were the sub-subplots. Thousand-kernel weight (TKW) Few studies include the incidence of this agronomic was higher and TW lower in 1996 than in 1997. Interaction year ϫ practice on yield and yield component losses. Leitch inoculation was not significant for any trait; year ϫ fertilization was and Jenkins (1995) observed that control of Septoria significant for yield and EPM 2 , and year ϫ cultivar was significant leaf blotch increased yield, with the magnitude of this for all traits except TKW. The separated analysis for each year indicated that additional N increased yield, EPM 2 , and KPE, but not effect greater at the higher rate of N applied. Johnston TKW or TW. Inoculation with S. tritici reduced yield and KPE, in et al. (1979) found a greater increase in yield in fertilized both years and TKW, TW, and EPM 2 in 1996. Differences between conditions compared with nonfertilized conditions when cultivars occurred for all traits except EPM 2 in 1996. The percentage fungicides were applied in only one of two years. reduction in yield, yield components, and TW due to the inoculation If the increase in the severity of the disease under N was similar in fertilized and nonfertilized conditions, despite the infertilization causes a reduction in yield and yield compocrease in the area under disease progress curve (AUDPC) values by nents, higher amounts of fungicides would be necessary N fertilization in 1996. Cultivar differences in tolerance is suggested.under high-N input systems. The aim of this work was to evaluate the influence of an early artificial infection of S. tritici on the yield, yield components, and TW 1974

Influence of Leaf Diseases on Grain Yield and Yield Components in Winter Wheat

“…We found that leaf spot diseases under conducive weather conditions can significantly reduce the number of productive tillers. This finding agrees with the results of Simón et al (2002). The researcher concluded that high severity of Septoria tritici could reduce the number of ears/m 2 .…”

Recent Advances on Integrated Foliar Disease Management with Special Emphasis in Argentina Wheat Production

“…However, Simón et al [82] reported that preventing early wheat infection by Septoria tritici could result in an increase of spikes.m -2 and grains.spike -1 .…”

“…Management practices such as N fertilization can also affect the expression of wheat foliar diseases [82,84] and the effectiveness of foliar fungicide application [72,82,84,85]. Increasing N rates may cause negative, positive or neutral effect on foliar disease severity, depending on the geographic location [86] and the type of disease.…”

“…The magnitude and direction of the influence of N supply on Septoria leaf blotch severity has been studied with contrasting results [85,87,88,89]. Simón et al [82,84,90] found that in conducive conditions, N fertilization increases the severity of Septoria leaf blotch and discussed the effect of different factors affecting the influence of N supply. Increasing N rates retarded tan spot development [66,69,73,91,92,93,94].…”

“…However, Bockus and Davis [95] suggested that N applications do not directly affect tan spot severity, but rather appear to reduce disease impact through delayed leaf senescence or that high N rates increase Septoria leaf blotch or tan spot severity due to an increase in crop biomass production, which creates a microenvironment conducive to fungal development in humid regions [82,84,85,96,97]. In addition, experiments carried out in Argentina indicated that yield increase and increase in yield components due to application of tebuconazole was similar in fertilized and non fertilized conditions, despite the increase in the area under disease progress curve under N fertilization [82].…”