**Appraisal of Salt Tolerance under Greenhouse Conditions of a** *Cucurbitaceae* **Genetic Repository of Potential Rootstocks and Scions**

**Giuseppe Carlo Modarelli 1, Youssef Rouphael 1, Stefania De Pascale 1, Gölgen Bahar Öztekin 2, Yüksel Tüzel 2, Francesco Orsini 3,\* and Giorgio Gianquinto <sup>3</sup>**


Received: 7 June 2020; Accepted: 3 July 2020; Published: 5 July 2020

**Abstract:** Soil salinization due to climate change and intensive use of water and soil is increasing exponentially. *Cucurbitaceae* species are cultivated worldwide and the identification of salinity tolerant genotypes to be used as rootstock or scion for securing yield stability in salt affected agricultural areas is a research priority. In the present greenhouse study, we assessed the response to salinity (0 mM a non-salt control and 150 mM NaCl dissolved in the nutrient solution) in the seedlings of 30 genotypes of cucurbits grown in a floating hydroponic system. The species tested included 16 genotypes of *Cucumis melo* L. (CM1-16), 6 *Citrullus vulgaris* Schrad. (CV1-6), 2 interspecific hybrids of *Cucurbita maxima* Duch. × *Cucurbita moschata* Duch. (CMM-R1 and 2), 4 bottle gourd (*Lagenaria siceraria* (Molina) Standl. (LS1-4)), 1 *Cucurbita moschata* Duch. (CMO51-17), and 1 luffa *(Lu*ff*a cylindrica* Mill. (LC1)) species. Results highlighted different morphological and physiological traits between the species and genotypes and a different response to salt stress. We identified *C. maxima* × *C.moscata* interspecific hybrid CMM-R2, melon genotypes CM6, CM7, CM10, and CM16 together with watermelon genotypes CV2 and CV6 and bottle gourd LS4 as salt tolerant genotypes and possible candidates as salt resistant rootstock to be introduced in grafting programs.

**Keywords:** NaCl; *Citrullus vulgaris* Schrad; *Lu*ff*a cylindrica* Mill; *C. maxima* Duch. × *C. moschata* Duch.; seedlings; morpho-physiological traits; grafting
