Leaf Water Potential and Crop Water Stress Index variation for full and deficit irrigated cotton in Mediterranean conditions

Deficit irrigation is a common practice to cope with limited water availability. A two-year field experiment was conducted in order to determine the water status of cotton crop (Gossypium hirsutum L.) under full and deficit irrigation conditions. The experiment was set up as a split plot design with four replicates, two main plots (irrigation treatments) and two sub plots (cotton cultivars). The lower (non-stressed) and upper (fully stressed) base lines for the determination of Crop Water Stress Index (CWSI) of cotton crop were estimated. Plant water status, expressed in terms of the water potential index (WPI) and CWSI, was measured throughout the growing seasons. The adopted irrigation schemes produced a clear differentiation among cultivars concerning their plant water status. Water shortage resulted in more negative leaf water potential and WPI and greater CWSI values. Leaf water potential, WPI and CWSI values, variation throughout both growing seasons, indicated greater adaptability for "Julia" in water stress conditions, while "Zoi" showed a significant water stress behavior during the phases of yield formation and ripening, even for the full irrigated treatment. In general, use of limited drip irrigation regime with 50% of water requirement had significant benefits in terms of saved irrigation water. (C) 2015 Published by Elsevier B.V.