Relationship of Seminal Roots Angle and Grain Yield of Winter Wheat Cultivars under the Continental Climate of Romania

Root system traits are important for accessing water from different soil depths, for nutrient capture from the soil profile and for plant anchorage influence on lodging resistance. All these can have complex and sometimes contradictory effects on grain yield. Wheat root system architecture is closely related to seminal roots axis angle in the seedlings stage. Our research is an attempt to define the most desirable seminal root angle for the continental climate of Romania, by studying its correlation with grain yield of several winter wheat cultivars tested in a representative sample of 108 yield trials, covering a wide range of environmental conditions. Correlation coefficients varied from -0.46 to +0.77, with an average of +0.17. In most yield trials correlations were positive, but low and mostly not significant. This suggests that for most of Romania and for regions with similar conditions, winter wheat breeding should aim at creating mainly cultivars with large seminal roots angle that could better use rainfall falling during the vegetation season, but also cultivars with a small seminal roots angle that can improve the access to water in the soil depth profile during severe drought conditions.