Application of grafting technique in watermelon cv. sugar baby (Citrullus lanatus cv. Sugar Baby ) under Salinity conditions

Salinity is a major environmental stress that causes severe damage to crop and horticultural products and also reduce plant biodiversity. Today with using grafting method overcome problem of soil salinity and ultimately, higher-quality products are yield of. In this study, water melon (cv. Sugar baby) was grafted on to the hybrid rootstocks of shintozwa (Cucurbita maxima×Cucurbita moschata), pepo (Cucurbita pepo), Buttle gourd (Lagenaria siceraria var gilan), Bitter cucumber (Citrullus colocynthis var kerman), Kermansha and Hamedan water melon (Citrullus lanatus var Kermanshah and hamedan), with using the hole insertion grafting method to the greenhouse.Grafted  and un-grafted plants that exposed to to 0, 30 and 60 mM NaCl, in greenhouse and field conditions were studied. The results of this study showed that the content of sodium and chlorine elements in the leave of grafted plants onto shintozwa and pepo rootstocks in both salinity treatments was lower than of un-grafted plants. Relative variations (percentage increase) of relative water content of leave of grafted plants onto shintozwa rootstock as compared to those of un-grafted plants were 21.16%. Also, the highest (430 g) and lowest (285 g) fresh weight of the shoot was related to sugar baby grafted onto shintozwa and un-grafted sugar baby respectively. The highest (8.76) and lowest (5.84%) of the TSS were related to the salinity level of 60 mM sodium chloride and control treatment (0 mM sodium chloride), respectively. There was no difference between the rootstocks in regarding to TSS, therefore, the studied rootstocks did not have a negative effect on the fruit quality of the watermelon of sugar baby cultivar. Grafted plants onto shintozwa and pepo rootstock showed the highest (18781 kg / ha) and the lowest yield (10154 kg / ha) respectively. Therefore, according to the results of this study, the shintozwa rootstock could be considered as a suitable rootstock for the watermelon transplant of watermelon of sugar baby cultivar. under conditions of salinity stress.