Cultivars mixture of two components in the management of multiple wheat diseases

Abstract

Wheat (Triticum aestivum L.) is affected by several diseases that reduce significantly the yield. In this study, carried out in 2012 and 2014, the mixtures of cultivars with different resistance level to disease were evaluated as a strategy to the management of leaf and ear diseases. The mixtures (treatments) were in the proportion of 100, 75, 66, 50, 34, 25 e 0% of the susceptible cultivar. Fusarium head blight (FHB) (Fusarium graminearum complex species) evaluation was performed in 400 ears per treatment. Severities of wheat leaf rust (Puccinia triticina), tan spot (Pyrenophora tritici-repentis) and powdery mildew (Blumeria graminis f. sp. tritici) were quantified on all leaf and considering only the flag one. FHB, tan spot and powdery mildew occurred in both crop seasons, while leaf rust occurred only in 2014. The reduction in the diseases intensities followed the reduction in the number of susceptible plants in the population, however, the mean severity of treatments was lower than the simple dilution of the susceptible population. The higher severity reduction, up to 41%, for leaf diseases occurred with up to 50% of the susceptible cultivar in the population. In conclusion, the cultivar mixture of two components is effective for reduction in the intensities of multiple wheat diseases, but additional measures will be necessary depending on diseases and climatic conditions prevailing during the crop season.