Dwarfing Rootstocks for High-Density Citrus Orchards

There is a worldwide trend regarding high density of fruit planting. In the last four decades, the Brazilian citriculture had increased the average planting density by more than 80%. The main reasons for this increase are the fast return on invested capital, the easiest management of cultural practices, and the control of strategies epidemics-associated (e.g., Huanglongbing). In that regard, the use and development of dwarf and semi-dwarf rootstocks are essential. The main dwarf rootstock known in citriculture is the Flying Dragon trifoliate orange [Poncirus trifoliata (L.) Raf. var. monstrosa (T. Itô) Swing.] which greatly reduces the canopies volume allowing the design of dense and ultra-dense orchards. Currently, several citrus breeding programs are producing new cultivars of dwarf and semi-dwarf rootstocks. In this chapter, citrus rootstocks with dwarfing potential were approached including physiological aspects, horticultural performance, and behavior to phytosanitary problems. In addition to Flying Dragon, there are other dwarfing rootstocks which are hybrids of trifoliate oranges, like citrandarins, citrangedarins, citrumelandarins, and citrimonianandarins. Dwarfing rootstocks are one of the leading alternatives for citrus orchards in high-density planting systems.