Determination of tolerance level of watermelon genetic resources to salinity and drought

In this study, salinity and drought responses of 65 watermelon genotypes have been investigated under the early growth phase. The goal of the work was tolerance levels of the watermelon genotypes. The plants have been grown in vermiculite. The watermelon genotypes have been grown with 200 mM NaCl for salinity stress and irrigation was stopped gradually for drought stress. Control plants without stress have also been grown. Young plant stage (24 days old plant) was used for screening studies and plants were not been grown until fruit stage. In order to identified tolerance and susceptible watermelon genotypes some morphological and physiological measurements and analysis have been realized; 0-5 scale evaluation for the symptomatic appearance of the plants, shoot fresh and dry weights, root fresh and dry weights, leaf number per plant, leaf area, SPAD-Chlorophyll meter reading, membrane injury index, leaf relative water content, leaf water potential, leaf osmotic potential, stomata conductance, leaf temperature, Na, K, Ca, and Cl concentrations of the shoot and root samples. All these parameters? differences in salinity and drought stresses via control have been calculated. Also the relationships among the parameters have been investigated.At the end of the study, large variations have been determined in watermelon genotypes for their salinity and drought responses. Sixty five watermelon genotypes have been classified; tolerant, mild tolerant and susceptible.