Rate of Change of Lodging Resistance, Yield, and Test Weight in Varietal Mixtures of Oats, Avena sativa L. 1

Two varieties of oats ( Arena sativa L.) ‘Simcoe’ and ‘Rodney’ were mixed in 10% incremeuts with ‘Garry’ and planted at two locations in Michigan. The resulting curves relate percentage mixture with percent lodging, yield, and test weight. On the basis of these curves both the slope and the shape of the curve relating percentage mixture to the response to stress are shown to be important factors in determining the success of a multi‐line variety. The slopes and the shapes of the curves for the three traits examined indicate that a 40:60 percent mixture of Rodney and Garry would be advantageous. Some mixtures are detrimental as witnessed by the curve for yield for the Simcoe mixture which dropped off rapidly in a nonlinear fashion when quite small amounts of Simcoe were added to Garry. In general, some mixtures may tend to inhibit pathogens and favorable mixtures can be found for lodging, test weight, and yield in oats. It is worth noting that the proportions of each line in a mixture may be quite important. In all probability, the success of a multi‐line variety will depend upon how carefully the varieties going into the mixture are chosen and how much consideration is given to the optimum proportions of each line. The random mixing of pure line varieties is likely to produce multi‐line varieties having expected values which are estimates of the mean values of the pure line varieties.