Hybrid rye (Secale cereale L.) as a good crop component to enhance yield stability in a winter cereal mixture

The knowledge on yield stability and variability of hybrid cultivars cultivated in a mixture with triticale over the years is limited. Therefore, a two-factorial experiment with the cropping system (pure vs. mixture) and the cultivar type (hybrid vs. open pollinated) as factors was conducted on chernozem soil in continental conditions (47 degrees 24 ' N, 7 degrees 19 ' E, 300 m a.s.l.) in three seasons to assess the effect of yield and yield stability of two cereal mixtures. Four approaches to yield stability calculations were used. Lower stability was noted for mixtures with open-pollinated rye cultivars compared with hybrid cultivars. The adjusted coefficients of variation (aCV) indicated that the yield was more stable in mixtures with the hybrid variety. The yield Stability Index Delta (SIDelta), which provides information about yield stability across the years, depends on the mixture components and weather fluctuation. The highest value of SIDelta was obtained for the hybrid cultivar in the mixture (SIDelta = 2.95), compared to the open-pollinated rye cultivar in the mixture (SIDelta = 0.47). The yield stability analyzed using linear regression (Yexp against Yobs for each crop mixture) indicated slope values less than one for the hybrid rye, suggesting higher mean grain yields in intercrops (observed yield) compared to the corresponding two sole crops (expected yield) across the three study years. The cultivation of the Palazzo hybrid rye in a mixture with triticale (cv. Borowik or Borwo) showed higher yield stability compared with that of the open-pollinated Amber cultivar. The study confirms that the inclusion of hybrid cultivars of winter cereals in mixed crops is justified by increased yield stability in comparison with open-pollinated cultivars. The use of hybrid rye as a component of mixed crops should be considered, as it shows higher productivity and greater yield stability than open-pollinated cultivars.