The development of vegetation cover in depleted rangelands of Mangla Watershed through introduction of suitable grass species is important for the production of good quality water and for increasing effective life if the Mangla reservoir by retarding its siltation rate. To find out suitable species for introduction in the Mangla watershed project area (dry sub-tropical) grass introduction trials with 39 cotypes of 14 species are being carried out in collaboration with Watershed Management Project of WAPDA in Missa Research Plot of Rawalpindi district since February,1973. On the basis of 1-1/2 years' observations on establishment, vigour, longevity and forage yield of these introductions, seven ecotypes of Bothriochloa pertusa, Cenchrus ciliaris, Chrysopogon aucheri, Dicanthium annulatum and Panicum antidotale have been considered successful. The study is still in progress.