  We show how to calculate the one-loop scattering amplitude with all gluons of
negative helicity in non-supersymmetric Yang-Mills theory using MHV diagrams.
We argue that the amplitude with all positive helicity gluons arises from a
Jacobian which occurs when one performs a Backlund-type holomorphic change of
variables in the lightcone Yang-Mills Lagrangian. This also results in
contributions to scattering amplitudes from violations of the equivalence
theorem. Furthermore, we discuss how the one-loop amplitudes with a single
positive or negative helicity gluon arise in this formalism. Perturbation
theory in the new variables leads to a hybrid of MHV diagrams and lightcone
Yang-Mills theory.
