Two field experiments were carried out on Nubian watermelon (Citrullus lanatus var.
Colocynthoide) during the summer season of 2009 and 2010 in the farm of Sakha Research
Station in Kafr El-Sheikh Governorate. The main objective of the study was to compare between
the four rootstocks: bottle gourd (Lagenaria siceraria), pumpkin (Cucurbita moschata), luffa
(Luffa cylindrical) and fig leaf gourd (Cucurbita ficifolia) with non-grafted plants. The study
included measurement of biochemical analysis of leaves and seeds, anatomical structure of the
grafting union and successful grafting percentage. In general, grafting plants onto bottle gourd
had higher nitrogen, phosphorus and potassium percentage, while the lowest values were
obtained from grafting plants onto fig leaf gourd. Grafting onto different rootstocks significantly
decreased oil content compared with non-grafted plants. On contrast, carbohydrate content was
increased by grafting. Nubian watermelon grafted onto luffa had the highest protein content,
while the lowest protein contents were obtained from grafting plants onto bottle gourd and from
non-grafted plants. Grafting onto different rootstocks significantly increased area of both xylem
and phloem compared with non-grafted plants. Also, grafting Nubian watermelon onto fig leaf
gourd and bottle gourd had the highest successful grafting percentage.