Varietal mix

Scale level :
Definition :

The varietal mix is an agricultural practice which sows a heterogeneous mix of varietals of the same species in a farm plot. Applying this agricultural practice confers many advantages which have been mainly demonstrated on cereal grains such as wheat, barley and sorghum. One of the objectives of the varietal mix is to find an alternative to crop protection products to limit the appearance of diseases and collateral damage.

One of the levers to prevent the spread of diseases is to mix and diversify the varietal resistances by focusing on the compensatory effects. The compensation mitigates the varietal sensitivity to a disease, by associating this varietal to other varietals resistant to the same disease. The varietal mix can limit the economic loss by ensuring the existing crop yield stability. Moreover, the non-biological origin stresses (like hydric stress) would be less frequent, thanks to the synergistic capacity of water absorption and fertilizer elements.

Technically, the adoption of varietal mix is not easy to set up. Precautions in the choice of varietals have to be taken before completing the mix. For instance, the varietal mix earliness and height should be relatively close, so that they can ripen at the same time, that the competition phenomenon should be limited, and that the harvest should be simplified. Mills can prefer pure varietals to mix them themselves so as to optimize bread-making.

The varietal mix remains an attractive alternative lever to crop protection products. In a global warming context, the varietal mix, more resilient and more adaptable, presents interesting perspectives to explore.

Published on 15 April 2020

Bibliographic references :

Cox CM, Garrett KA, Bowden RL, Fritz AK, Dendy SP, Heer WF. 2004. Cultivar mixtures for the simultaneous management of multiple diseases: tan spot and leaf rust of wheat. Phytopathology.  Sep;94(9), pp 961-969. doi: 10.1094/PHYTO.2004.94.9.961. Accessed 01/04/20.

Dai, J. J. Wiersma, D. L. Holen Jr. 2012. Performance of Hard Red Spring Wheat Cultivar Mixtures. Agronomy journal, vol 104 (1), pp 17-21. doi.org/10.2134/agronj2011.0123. Accessed 01/04/20

Maria Finckh, Edward Gacek, Henriette Goyeau, Christian Lannou, Ueli Merz, Christopher Mundt, Lisa Munk, Jadwiga Nadziak, Adrian Newton, Claude de Vallavieille-Pope, et al. 2000. Cereal variety and species mixtures in practice, with emphasis on disease resistance. Agronomie, EDP Sciences,2000, 20 (7), pp.813-837. doi:10.1051/agro:2000177. hal-00886081. Accessed 01/04/20.

To quote this definition or part of it :
Lucie Anchordoquy, Alix Aymonier, Marie-Hélène Robin. 2020. Varietal mix : Definition. Dictionnaire d'Agroecologie, https://dicoagroecologie.fr/en/encyclopedia/varietal-mix/

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