Agroscope Changins-Wädenswil (ACW), Nyon

Winter wheat cultivars in organic or extensive conditions

For the varietal study of winter wheat, two experimental networks were carried out between 2002 and 2004, one according to the requirements of organic farming and the other in extensive conditions. The purpose of the comparison of the networks was not to explain the differences between crop management in organic farming or extensive conditions, but to highlight possible interactions between crop management and varieties. In spite of important differences on the level of farming techniques, the concordance of results in the two networks was excellent. Except for precocity, the analysis of variance did not show any interaction between variety X crop management, for the other parameters.The average yield in the organic network corresponded to 71% of the yield obtained in extensive condition, the coefficients of correlation (r) between the two crop managements varied between 0,76 and 0,88. The stems are on average 7% shorter and lodging occurred 22% less frequently in organic conditions. The varieties are on average half a day earlier in ear appearance in organic farming conditions (r from approximately 0,97). The hectolitre weight and the thousand-kernel weight are practically identical in the two ways of cultivation (r from 0,90 to 0,99). A simulation shows that the test of the agronomic and technological value (VAT) is more selective in organic farming conditions than in extensive ones, for all the types of varieties, i.e. organic or extensive varieties. Based on these data, one can conclude that the varieties of winter wheat behave in a very similar way in organic farming and in extensive conditions.

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