A blade for a rotor of a wind turbine having a substantially horizontal rotor shaft, the rotor comprising a hub, from which the blade extends substantially in a radial direction when mounted to the hub, the blade comprising: - a profiled contour comprising a pressure side (52, 452, 552) and a suction side (54, 454, 554) as well as a leading edge (18, 56) and a trailing edge (20, 58) with a chord extending between the leading edge (18, 56) and the trailing edge (20, 58), the profiled contour generating a lift when being impacted by an incident airflow, - the profiled contour in the radial direction being divided into a root region (30, 130, 230, 330, 430) with a substantially circular or elliptical profile closest to the hub, an airfoil region (34, 134, 234, 334, 434) with a lift generating profile furthest away from the hub, and a transition region (32, 132, 232, 332, 432) between the root region (30, 130, 230, 330, 430) and the airfoil region (34, 134, 234, 334, 434), the transition region (32, 132, 232, 332, 432) having a profile gradually changing in the radial direction from the circular or elliptical profile of the root region (30, 130, 230, 330, 430) to the lift generating profile of the airfoil region (34, 134, 234, 334, 434), wherein - the airfoil region (34, 134, 234, 334, 434) comprises a plurality of segments comprising at least a first longitudinal segment (140, 240, 340) extending along at least 20% of a longitudinal extent of the airfoil region (34, 134, 234, 334, 434), the first longitudinal segment (140, 240, 340) comprising a first base part (141, 241, 341, 441) having a leading edge (18, 56) and a trailing edge (20, 58) with a chord extending between the leading edge (18, 56) and the trailing edge (20, 58), characterised in that - the first base part(141, 241, 341, 441) has an inherent non-ideal twist, so that an axial induction factor of the first base part (141, 241, 341, 441) without flow altering devices (80, 180-182, 280, 380, 480) at a design point deviates from a target axial induction factor, and wherein - the first longitudinal segment is provided with a number of first flow altering devices (80, 180-182, 280, 380, 480) arranged so as to adjust the aerodynamic properties of the first longitudinal segment such that this deviation is compensated for by using the first flow altering devices (80, 180-182, 280, 380, 480) in order to adjust the design lift and inflow properties to appropriate near-optimum axial induction factor as a function of the blade radius and obtain correct lift and drag coefficients at a given angle of attack to substantially meet the target axial induction factor at the design point, wherein the target axial induction factor is close to the aerodynamic optimum target axial induction factor, the target axial induction factor lies in the interval between 0.25 and 0.4. - a profiled contour comprising a pressure side (52, 452, 552) and a suction side (54, 454, 554) as well as a leading edge (18, 56) and a trailing edge (20, 58) with a chord extending between the leading edge (18, 56) and the trailing edge (20, 58), the profiled contour generating a lift when being impacted by an incident airflow, - the profiled contour in the radial direction being divided into a root region (30, 130, 230, 330, 430) with a substantially circular or elliptical profile closest to the hub, an airfoil region (34, 134, 234, 334, 434) with a lift generating profile furthest away from the hub, and a transition region (32, 132, 232, 332, 432) between the root region (30, 130, 230, 330, 430) and the airfoil region (34, 134, 234, 334, 434), the transition region (32, 132, 232, 332, 432) having a profile gradually changing in the radial direction from the circular or elliptical profile of the root region (30, 130, 230, 330, 430) to the lift generating profile of the airfoil region (34, 134, 234, 334, 434), wherein - the airfoil region (34, 134, 234, 334, 434) comprises a plurality of segments comprising at least a first longitudinal segment (140, 240, 340) extending along at least 20% of a longitudinal extent of the airfoil region (34, 134, 234, 334, 434), the first longitudinal segment (140, 240, 340) comprising a first base part (141, 241, 341, 441) having a leading edge (18, 56) and a trailing edge (20, 58) with a chord extending between the leading edge (18, 56) and the trailing edge (20, 58), characterised in that - the first base part(141, 241, 341, 441) has an inherent non-ideal twist, so that an axial induction factor of the first base part (141, 241, 341, 441) without flow altering devices (80, 180-182, 280, 380, 480) at a design point deviates from a target axial induction factor, and wherein - the first longitudinal segment is provided with a number of first flow altering devices (80, 180-182, 280, 380, 480) arranged so as to adjust the aerodynamic properties of the first longitudinal segment such that this deviation is compensated for by using the first flow altering devices (80, 180-182, 280, 380, 480) in order to adjust the design lift and inflow properties to appropriate near-optimum axial induction factor as a function of the blade radius and obtain correct lift and drag coefficients at a given angle of attack to substantially meet the target axial induction factor at the design point, wherein the target axial induction factor is close to the aerodynamic optimum target axial induction factor, the target axial induction factor lies in the interval between 0.25 and 0.4.