Effect of substrate on vegetative growth, quantitative and qualitative production of muskmelon (Cucumis melo) conducted in soilless culture

Greenhouses heated and irrigated by geothermic water, constitute a promoter sector in the South of Tunisia. However, simultaneous salinity of sand and water of irrigation limits amply, the development of this sector. To control salinity, it seems efficient to adopt interesting agricultural techniques like soilless culture. The selection of suitable media is the key that ensures the success of this technique, seeing that the adoption of not standardized one, limits the correct nutrient solution management so the development of plant. The substrate selection must consider technical and economical implications. In this framework, two ubiquitous substrates of the South of Tunisia, sand and compost of dry palms, were compared to the imported media, perlite, for soilless culture of muskmelon (Cucumis melo). This study was based on the vegetative growth, quantitative and qualitative production. Results have shown that local substrates have simulated, in relation to perlite, strong and deep roots that permit an effective absorption of nutrients. Subsequently, leaves were larger, their content in fresh and dry matter were higher and stems were taller. This superiority was sustained by superiority of index of growth, NAR. This behavior has reverberated on precocity and yield that were greater on these two media. As regard to external characteristics of fruits, firmness and diameter were higher particularly on compost. With exception of pH, gustative quality was not affected by type of substrate.   Key words: Greenhouse, muskmelon, substrate, vegetative growth, quantitative production, qualitative production.