In MANETs (Mobile Adhoc Network) judgment in optimal reliable routing path between source and destination is a challenging task because of the mobility nature of nodes and is deficient in the infrastructure of the network which is so dynamic. So the objective of this paper is to identify an optimal reliable ordered routing paths between source and destination nodes in MANET.To meet the above challenging task the paper focus on an new novel approach in Genetic Algorithm called Parametric fitness based Genetic Algorithm.Proposed algorithm hybridized with classification model rough sets as one key sub component which offers better accuracy results.