The Australian Centre for International Agricultural Research (ACIAR) funded Graeme Sanderson (NSW Department of Primary Industries) to travel to Brazil to participate in the 13th International Citrus Congress (ICC). More than 1000 delegates attended the conference from 25 countries. The conference provided an opportunity for Graeme to learn about the latest varieties and breeding programs from around the world.
Huanglongbing (HLB) control and management strategies dominated the congress program. HLB is the most significant global issue for the citrus industries of most countries. Citrus breeding and genomics holds promise that tolerance can be imparted to both scions and rootstocks, but it is a genetic modification process that has yet to be developed for the commercial world.
Consumer perception of genetically modified (GMO) citrus will be an issue that will need consideration in future years.
There has been significant process down the genetic modification pathway for HLB management since the previous congress in Valencia, Spain four years ago. Australia and its biosecurity preparedness directly benefits from having access to all the research and on-going developments in understanding, controlling and managing HLB in major citrus producing countries.
In parallel, there has been significant progress on understanding the origins of citrus and the hybrid mix of modern commercial cultivars. This has become more important as different citrus species have varying tolerances to HLB infection. A common parent in many citrus cultivars is the citron, which has some tolerance to HLB. Sour orange has also been shown to have some tolerance to HLB and a NSW DPI citrus rootstock breeding program at Gosford in the early 1960s created and screened a number of Trifoliata orange × sour orange hybrids for their suitability as rootstocks. There is now the potential to test them outside Australia for their tolerance to HLB. The mother trees of these hybrids are held in the Dareton arboretum collection. There is also a new collaboration between the Queensland Department of Agriculture and Fisheries and the University of Florida examining HLB tolerance in Australian native citrus.
Citrus breeding programs in South Korea and Uruguay are developing new mandarin hybrids that are worthy of assessment in Australia. These might come into Australia under cultivar management and evaluation agreements in the future. Several public access varieties were also identified and recommended to Auscitrus for introduction to Australia after discussions with an Italian citrus breeder and Chilean industry representatives.