Citrus trees are propagated by budding the variety/scion onto specially grown and suitable-compatible rootstocks. All the listed varieties are generally available on a range of rootstocks i.e. P. trifoliata, Swingle citrumelo, Cox hybrid, and Troyer or Carrizo citrange.
Different rootstocks will help adapt citrus to varying climatic (cold) and soil conditions i.e. light-sandy, heavy-clay, alkaline, phytophthora root rot-replant or nematode sites.