Sustainability of agriculture could be increased through implementing and improving intercropping that enriches biodiversity in the fields. However, targeted breeding programmes on suitable varieties for crop mixtures are seldom found. To define specific selection traits, a trial has been started in organic and conventional fields on wheat-pea crop mixture in 2018 using 9 winter wheat genotypes having different types and diversity levels drilled with two different densities with and without a winter pea cultivar intercropped.

After assessing several agronomic, phenotypic and resistance traits, we have found that in most cases the entries responded negatively to the presence of pea, unlike grain yield of a landrace in conventional field. Most of the varieties and variety mixtures headed later in mixed plots, and they developed significantly less ears in the presence of pea. Comparing the pure and the mixed stand in both management systems, only a landrace and a population developed similar number of ears. However, significantly different ear-numbers were found between the entries only in the organic pure stands. Few significant differences were observed for the effect of pea on resistance of wheat to the main leaf diseases: in the presence of pea, only a robust, an extensive variety and a 2-way variety mixture showed significantly higher susceptibility to yellow rust in organic field with low sowing density. No significant effect of sowing density was found for disease susceptibility.

In general, a dwarf (intensive) wheat cultivar was the most sensitive to intercropping, while an extensive (relatively tall) modern cultivar and a variety mixture composed of it had the highest grain yield in conventional field, harvested both from pure and mixed stand. The landrace had the lowest yield in conventional field, while no significant difference between the entries was found for grain yield in organic field. Grain yield was negatively affected also by weeds regarding the dwarf intensive variety, while only the extensive variety drilled with high density responded with significantly higher plant stand to the presence of weeds. A targeted breeding program has been started, where selection of lines occurs in crop mixture taking into account specific selection criteria highlighted above.

Acknowledgement. This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 727217 (REMIX). The information contained in this communication only reflects the author’s view. The Research Executive Agency is not responsible for any use that may be made of the information provided.