Evaluation of salt tolerance in rootstocks of Cucurbitaceae

Research was carried out at the Experimental Farm of University of Tuscia to investigate the salt tolerance of different commercial rootstocks for watermelon in a closed soilless system (NFT). A split-plot design with three replicates was used to compare six concentrations of NaCl (main plot) x five genotypes (sub-plot) which included four commercial rootstocks widely used for watermelon crop and a watermelon cultivar. The salinity treatments were: 0, 20, 40, 60, 80 and 100 mM of NaCl. Genotypes were four commercial rootstocks of Lagenaria spp. ['Emphasis' (S&G) and 'Macis' (Nunhems)] and Cucurhita spp. ['P360' (SAIS) and 'Polifemo' (Esasem)] and a cultivar of watermelon [(Citrullus lanatus (thumb.)Mansf.- cv 'Star' (Petoseed)]. Cucurhita rootstocks produced higher dry weight biomass of shoots and roots than those observed on Lagenaria spp. and watermelon cultivar. Moreover, increasing NaCl concentration decreased shoot dry weight of all genotypes and especially on watermelon cultivar. Finally, the higher salt tolerance observed in Cucurhita spp. and Lagenaria spp. compared to watermelon cultivar was associated to a lower Na uptake.