Grafting vegetable crops to manage plant-parasitic nematodes: a review

Vegetables constitute 12% of world agricultural produce. Solanaceous and cucurbitaceous crops constitute the major share of vegetable production, but their productivity is greatly impaired by plant-parasitic nematodes, among which root-knot nematodes pose the greatest threat. Due to climate change, water scarcity, shrinking of arable land, and ill effect of pesticides, a major shift in world agriculture is taking place toward sustainability, including organic and protected farming of high-value vegetable crops year-round. Grafting offers a sustainable alternative to conventional and transgenic breeding for nematode resistance. The technique can potentially reduce the phytonematode damage relying on several factors. These include R gene-mediated plant responses, efficient cross talk of defensive genes, alteration of plant metabolism and nutrient mobility, changes in plant vigor and physiological attributes, and modification of rhizosphere microbial community. Additionally, epigenetic factors also determine the success of graft union between the scion and rootstock. Grafting should also be included as a tool in integrated nematode management practices. Studies on identifying potential rootstocks and using grafted vegetable crops to manage nematode incidence are exhaustive but scattered. Here, we review the current status of vegetable grafting for nematode management using resistant rootstocks in both open-field condition and greenhouses. This is the first review, which compiles and summarizes the information on managing nematodes using grafted vegetables. We conclude the review with futuristic research perspectives of grafting that may aid in improving vegetable productivity in a sustainable manner.