Genetics, breeding and selection of rootstocks for Solanaceae and Cucurbitaceae

Abstract

In many parts of the world, grafting is a routine technique used in continuous cropping systems. It was first commonly used in Asia during the late 1920s by grafting watermelon ( Citrullus lanatus (Thunb.) Matsum. and Nakai) onto pumpkin [ Cucurbita moschata Duchesne ex. Poir] rootstocks. Use of rootstocks can enhance whole plant biotic stress responses by improving plant vigor through vigorous attainment of soil nutrients, avoidance of soil pathogens and tolerance of low soil temperatures, salinity, and wet-soil conditions. The type of rootstock affects scion growth, yield, and fruit quality. Grafting is rare in the United States, due in part to cost and availability of facilities, but with continued loss of quality disease-free farmland along with the phase-out of methyl bromide, vegetable grafting is an attractive option. However, grafting cost, limited grafting facilities, methyl bromide exclusions, shipping costs, and legal issues associated with contracting for grafted plant delivery have caused slow acceptance of this option. This review discusses recent literature on vegetable grafting with a focus on the genetics and breeding of the rootstock, and delves into current issues affecting the grafting industry. Issues affecting acceptance of grafting in the United States and Canada are highlighted.