The study of the Inga sort it represents an important contribution for the knowledge of the flora of the plain of flooding of the high river Paran. The knowledge of the genetic differentiation of populations of this sort will contribute in the attainment of information concerning the distribution of these species in different environments of this area, having disclosed its preferential habitat, beyond supplying to ecological subsidies and information revegetao. Thus, it was objectified to verify if three populations of the Inga sort (Mimosaceae) in ripria area in the plain of flooding of the high river Paran, in Porto Rico (PR), are genetically isoladas.FUNDAMENTAO TERICAA alagvel plain of the high river Paran constitute the last stretch of this river, free of barrages, in Brazilian territory (AUGUSTIN et al., 1995), presenting flooding pulses that they confer a particular dynamics to the ecosystem, with annual fluctuations of the water level that oscillate between phases terrestrial and aquatic, where the primary production depends on the composition of the water and the fertility of the sediments during the aquatic phase, and of the humidity of the ground during the terrestrial phase (AUGUSTIN et al., 1995; JUNK, 1997; UEM.NUPLIA/PELD, 2000). The Plain of Flooding of Alto Rio Paran (PIARP) presents diverse antrpicos uses as mining, agriculture, cattle, fish and tourism. The state of conservation of the plain is space heterogeneous, obeying a gradient that goes of bigger alteration in next areas to the lesser cities and each time in the measure where it increases its distance of the urban centers (AUGUSTIN and ZAHWSKI, 1996). These riprias areas are recognized for the Ambient Legislation of Brazil as Areas of Permanent Preservation for Law 4,771, of 15 of September of 1965 e, in the stretch of the high river Paran called alagvel plain, these understand 500 bands of m of width and present the vegetal covering in varied disturbance degrees (SOUZA et al., 1997).