The objectif of this communication is to present a general view of a rubber bredding programme beginning with a description of the genetic resources management, then showing the main limits to genetic gain imposed by the biology of the plant. We present with more details some aspects related to the central question of the estimation of the genetic worth. Then we present the project of "Markers Assisted Selection" which is implemented by CIRAD with partners and discuss how it can help to overcome some difficulties. Much of the ideas developed are issued from the CIRAD-IDEFOR cooperation and exeperience gained in Ivory Coast.