Fungal communities and health status of roots of winter wheat cultivated after oats and oats mixed with other crops

Abstract

Health status of winter wheat roots and thecomposition of wheat root fungi were studiedover 1996-1999 following the cultivation ofoats in a pure stand and mixed with otherplants as forecrops. The infection of wheatroots by >Gaeumannomyces graminis wasobserved to be largely dependent on the kind offorecrop; the best being oats in a pure stand,and then oats with pea or lupin mixtures. Inthe emergence and shooting phases, saprophyticfungi were dominant, while in the stage of harddough stage mainly pathogenic fungi, especially>G. graminis were common. The pathogenicfungi were mostly represented by >G.graminis and >Fusarium spp., while >Rhizoctonia spp. were much less frequent.The composition of the fungal communitydepended considerably on the forecrop anddevelopment phase of the plant. The kind offorecrop significantly affected the frequencyof infection by >G. graminis. The highestnumber of isolates was obtained from wheat rootsof crops grown after a mixture of oats andbarley.