Soils from Ãuble's and BiobÃo's Andean foot-hills dryland areas were used to study the incidence of the take-all disease on wheat, caused by Gaeumannomyces graminis var. tritici, in different crop sequences. The highest incidence was measured under wheat monoculture. In field trials, sequences including rape (Brassica napus L.) and lupine (Lupinus albus L.) showed lower numbers of severely affected roots and higher grain yields of the cereal, in relation to the other crop sequences studied (wheat after oats, natural pasture, burned wheat stubble, undisturbed wheat stubble, and plowed wheat stubble). Nevetheless, in pot trials, no differences among the crop sequences were observed. |