Endophytic Fungi in Four Winter Wheat Cultivars (Triticum aestivum L.) Differing in Resistance Against Stagonospora nodorum (Berk.) Cast. & Germ. =Septoria nodorum (Berk.) Berk.

Abstract

AbstractFour winter wheat cultivars with different levels of resistance to Septoria nodorum were investigated at four locations during two vegetation periods. Forty plants per cultivar and site were collected at random at seven defined growth stages from crop emergence to harvest. Samples from roots, culms, leaves, glumes and kernels were examined for the occurrence of endophytic fungi after surface sterilization. 83% of the 26944 isolates sporulated and were assigned to 213 species. The most frequent were: Septoria nodorum (20.1%), Alternaria tenuissima (9.8%), Epicoccum purpurascens (9.1%), Idriella bolleyi (6.9%), Fusarium graminearum (5.3%), Fusarium culmorum (4.0%), Cladosporium oxysporum (3.7%), Didymella exitialis (3.1%), Fusarium nivale (2.8%) and Rhizoctonia solani (2.1%). Each species occurred preferentially in one or more plant organs. A factorial analysis of variance showed that plant organ, sampling site, vegetation, period and cultivar in decreasing order of importance influenced the quantitative and qualitative composition of the fungal populations. No relationship between endophytic fungi was found to be constantly antagonistic or mutualistic. Septoria nodorum was isolated mainly from culms. The number of S. nodorum isolates differed significantly between cultivars in culms and glumes but not in flag leaves. The results are discussed in relation to resistance breeding and the effect endophytic fungi, might have on yield.