  It was proposed in hep-th/0403047 that all tree amplitudes in pure Yang-Mills
theory can be constructed from known MHV amplitudes. We apply this approach for
calculating tree amplitudes of gauge fields and fermions and find agreement
with known results.The formalism amounts to an effective scalar perturbation
theory which offers a much simpler alternative to the usual Feynman diagrams in
gauge theory and can be used for deriving new simple expressions for tree
amplitudes. At tree level the formalism works in a generic gauge theory, with
or without supersymmetry, and for a finite number of colours.
