Troyer and Carrizo citrange
Hybrids of sweet orange and trifoliate orange are referred to as citranges. These two citranges are virtually indistinguishable and are hybrids of Washington navel and P. trifoliata. Troyer citrange is the most widely used rootstock in Western Australia.
Both rootstocks are cold hardy, produce vigorous trees and perform well on most soil types. They will not grow well in calcareous soils or under saline conditions. Trees on these rootstocks can be prone to micronutrient deficiencies, especially on calcareous soils.
They are tolerant of the citrus tristeza virus, citrus nematode (Tylenchulus semipenetrans) and phytophthora root rot but are susceptible to severe strains of the citrus exocortis viroid. Both are responsive to viroid dwarfing and are suitable for use in replant sites.
Troyer and Carrizo citrange are compatible with most common citrus varieties except Eureka lemon. There is a long-term problem with Imperial mandarins that may be related to overgrowth at the bud union. Compatibility with some minor varieties is unknown.
Troyer and Carrizo are grown under a range of conditions in WA. They are commonly known as ‘best bet’ rootstocks throughout the state and have performed well on the deep sands at West Gingin and heavier clay loams at Harvey.