Abstract: Supported Ziegler-Natta catalyst component adapted for the polymerization of ethylene is provided. More specifically, certain organomagnesium compounds (e.g., dibutylmagnesium) which do not contain an oxygen linkage between the organo moiety and the magnesium are impregnated into a porous inorganic oxide support (e.g., agglomerated silica particles) to form a first reaction product. The first reaction product is halogenated, e.g., with HCl, to convert the organomagnesium derived component to MgCl2 thereby forming a second reaction product. The second reaction product is then treated with a transition metal compound (e.g., TiCl4), a particular type of electron donor (e.g., 2,6-dimethyl pyridine) and optionally at least one Group 2 or 13 organo metal compound (e.g., diethylaluminum chloride). The combination of the particular organomagnesium compounds and electron donor impart a low melt flow ratio and enhanced activity to resulting catalyst component.