Considering that (i) one of the most serious problems facing the Mediterranean Region is related with water due to the limited amount of natural water resources and the fact that neither the increase in population of this region nor the foreseen climatic c hanges are going to contribute favourably to improve the regional situation as far as water is concerned and (ii) improving the water consumption by users and uses and plant breeding for efficient water and nutrient use is one of the areas addressed in the Call (INCO-2002-B. 1.2) together with water treatment (INCO-2002-B. 1.3) the objectives of this Proposal are: (i) The development of selective polymeric materials (cheap to produce) for desalination of seawater, post-irrigation water and soil with the aim of developing a most effective technological approach than the existing ones. (ii) The use of biotechnological modes and means for promoting efficient and nutrient use of water by plants, improving their immunity and resistance towards diseases and droughts. To achieve these objectives the following steps are to be undertaken. Step 1. Selection of main strategic cultures of three Mediterranean Countries as Pilot sources for vegetation experiments based on socio-economic importance, crops quality and structure, agronomical, agrochemical and climatic conditions of their cultivation. Step 2. Synthesis, characterisation of calixchitin polymers for desalination of seawater, post-irrigation water and soil, followed by their application at Laboratory and Pil ot Plant scale. Step 3. Qualitative and quantitative assessment of the industrial potential de-sorption solutions resulting from sea, post-irrigation waters and soil. Step 4. Design of material phenylpropanoid polymeric derivatives with the capability to f unction as a plant growth regulatory, fertilizers, quality enhancers for the protection of crop quality and productivity under drought conditions. Step 5. Combinati