R. Cohen,
M. Elkabez,
M. Edelstein

Vegetable grafting has been used in Israel for the last 20 years. The original and main purpose of this practice is reducing the occurrence of soil-borne diseases and pest damage. Nevertheless, the use of grafted plants has additional benefits and disadvantages compared to non-grafted plants; thus, evaluating these factors in addition to economic considerations has led to the common practices applied today. Melon grafting is used mainly for the spring planting in light of the long growing season. Grafted plants may cope better with low soil temperatures prevailing at the time of planting; they commonly produce higher yields and help to prevent soil-borne diseases that occur following fruit maturity. In the summer and fall seasons, the grafted transplants' high price and relatively low yield do not justify grafting, whereas managing soil-borne diseases effectively is accomplished using inexpensive chemical alternatives. Similarly, grafted cucumbers are used mainly for the long winter growing season. These plants can manage better with low soil and air temperatures, and may offer good protection against crown rot caused by Fusarium oxysporum f. sp. radices-cucumerinum. In certain cases, tolerant rootstocks provide partial protection from infection by soil-borne virus Cucumber green mottle mosaic virus (CGMMV). Most of the watermelons grown in Israel are grafted. The main reason for this approach is to reduce the impact of damage caused by soil-borne pathogens such as Macrophomina phaseolina or to avoid soil fatigue, which is very common in watermelon production if crop rotation is not properly used. Grafted watermelons produce higher yields but their fruit quality is often diminished. To overcome this obstacle, field trials are being carried out in order to find the best rootstock-scion combination. In certain cases, watermelon rootstocks can be used. The challenges involved with Cucurbita and watermelon rootstock breeding and its effects on fruit quality and on plant performance is discussed.