The paper presents a way of constructing quasimonotone nonautonomous
systems ensuring x-stability of the nonautonomous system. There are
described extensions quasimonotone with respect to an arbitrary cone,
Perron condition and invariant surface stability under perturbations U-stability on the set of non wandering points is proved to imply u-stability
of quasimonotone nonlinear system and exponential u-stability on
minimal attraction center provides u-stability of the total systems
Examples are available.