Untested: Citrus macrophylla
This rootstock is untested in Western Australia but has been used in some orchards in eastern Australia. It is understood that commercial interest is based on its precocious fruiting habit. Trees are reputedly very vigorous in the early years and then slow quickly once fruiting commences.
Although fruit is large, fruit quality is reported to be poor with low sugar and juice content. It is very susceptible to tristeza virus, xyloporosis viroid and cold damage, however is resistant to phytophthora root rot and is salt-tolerant.
Fruit quality issues, particularly in sandy soils, mean that fruit may struggle to meet local and national standards. There is no strong recommendation for its use in Australia.
New rootstock evaluation
A number of new rootstock evaluation trials have commenced in Western Australia in recent years and these include some that were selected for tolerance to saline conditions and others which are hybrids of mandarin and trifoliata. It is anticipated that some results from these trials will be available in a few years time although it should be noted that rootstocks trials take many years to mature and provide conclusive results.
Six new Chineese rootstocks (Zao Yang, Tanghe, Ghana, Donghai, Anjiang hongju and Caoshi xiangju) were released in 2017 and seed of these is now available through Auscitrus. These rootstocks have not yet been extensively tested in Australia, however further information about their performance in different Australian regions will become available over time.
Acknowledgements
Mark Skewes from the South Australian Research and Development Institute provided information on C35 citrange incompatibility with Navelina.
Graeme Sanderson from New South Wales Department of Primary Industry provided information on C35 incompatibility with Eureka lemons.
This page updates Farmnote 16/2004 Citrus rootstocks for Western Australia by Kevin Lacey.