By Lamiaa Mahmoud and Manjul Dutt Utilizing tolerant rootstocks to combat HLB is a long-term management strategy that can help sustain productivity and enhance tree survival, especially when implemented alongside other HLB management approaches. Australian limes are tolerant to HLB, and their DNA can be incorporated into HLB-susceptible citrus using conventional breeding methods to enhance tolerance to HLB. Over the …
Top Florida Citrus Varieties and Rootstocks
Sour orange jumped six spots from the prior year to become the most-budded rootstock in Florida citrus nurseries in 2023–24. Rootstock US-942 had held the top spot for at least the last three years. Valencia SPB-1-14-19 easily maintained its spot as the most-budded variety clone. It has held the top spot for at least four straight years. The number of …
Survey Shows Popular Scions and Rootstocks
The Florida Citrus State of the Industry Survey seeks input from growers on key issues affecting their groves. The survey has been conducted for many years, has tracked the trajectory of HLB and reported on production practices. While not a scientific survey, it has reflected general trends over the years. Last month, we published results on trunk-injection therapy and the …
Rootstocks Show Drought Tolerance in Brazil
The drop in Brazil’s 2024 citrus harvest is due, among other factors, to the long period of drought observed in the Citrus Belt, according to Fundecitrus. Mitigating problems related to periods of drought is the objective of several studies being conducted by Fundecitrus, Embrapa Cassava and Fruits, Coopercitrus Credicitrus Foundation and the Agronomic Institute (IAC). One of these studies takes …
More SuperSour Rootstocks Under Study
“Superior New Rootstocks Can Make Citrus Profitable Again” is the headline of a recent U.S. Department of Agriculture Agricultural Research Service (USDA ARS) article. Kim Bowman, research geneticist at the USDA Horticultural Research Laboratory in Ft. Pierce, Florida, write the article. A slightly edited version follows: The rootstock and root system are what make trees strong enough to survive and …
Rootstocks and OTC
The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center hosted a May OJ Break educational seminar. Ute Albrecht, UF/IFAS associate professor of plant physiology, spoke during the event and gave an update on oxytetracycline (OTC) therapies being applied in citrus groves over the past two seasons. She gave a summary of research she …
CITRUS NURSERY SOURCE: A Day of Learning About New Rootstocks and Varieties
By Peter Chaires The U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) U.S. Horticultural Research Laboratory and Florida Citrus Research Foundation (FCRF) jointly held an open house, variety display and field tour at the W.H. Whitmore Foundation Farm between Leesburg and Groveland in early December. This annual event provides a great opportunity for industry members to see the latest innovations in …
Rootstocks and More Showcased at Field Day
In early December, the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) hosted its annual A.H. Whitmore Foundation Farm field tour and variety display in Groveland, Florida. The event was well attended and showcased the USDA-ARS citrus scion and rootstock breeding program. Attendees loaded up for a hayride and guided tour through the grove. One stop showcased the cooperative work the …
Rootstocks Influence Cold-Hardiness of Georgia Tangos
Since the Christmas freeze of 2022, University of Georgia Lowndes County Extension Coordinator Jake Price has been conducting cold-hardiness ratings to see how Georgia citrus varieties were influenced by their rootstocks. He focused on Tango performance in a recent report and declared US-1516 “the clear winner” in providing cold-hardiness. Since January of 2023, Price has conducted ratings on how much …
Breeder Advice on Nutrition, Scions and Rootstocks
Citrus breeder Jude Grosser recently shared tips on tree nutrition and discussed some scion/rootstock combinations that should work well for trees producing juice oranges. NUTRITIONGrosser became very interested in citrus nutrition several years ago in an effort to keep his newly bred trees healthy in the face of HLB. The University of Florida Institute of Food and Agricultural Sciences professor …
Nutrient Uptake Potential of Rootstocks
The objective of a new study published in HortScience was to evaluate and understand the nutrient uptake potential of citrus rootstocks. Conducted by University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers, it is one of the first citrus studies to report nutrient uptake efficiency and the potential of rootstocks. The information presented in the study can be …
Stay Current With Research on Rootstocks
By Jude Grosser The ultimate solution to the HLB problem is having good rootstocks that can mitigate or eliminate the disease’s impacts in any grafted commercial scion. With this, growers could profitably grow any scion, including grapefruit, Hamlin or even Murcott. Thus, rootstock breeding efforts focus on directly screening new rootstock hybrids for their ability to confer HLB tolerance or …
Chinese Rootstocks Show Promise in Australia
Preliminary data from an Australian research project suggest Chinese rootstocks No. 24 and 85-24 are having a dwarfing effect on citrus tree growth and will be candidates for future high-density cropping systems. Citrus Australia reported that those rootstocks have strong potential in heavy soils, and that results on deep sandy loam soil are also very encouraging. Tahir Khurshid from the …
Progress in Developing Improved Citrus Rootstocks to Mitigate HLB
By Jude Grosser, Manjul Dutt and Fred Gmitter Exploiting citrus genetic diversity is the key to defeating HLB. Plant species have survived for millennia with evolving, hostile pathogens. This is possible through natural selection within genetically diverse populations. Tolerant or resistant individuals survive and intermate, get through the bottleneck, and the species evolves. Current citriculture is based on extremely limited …
Releasing Rootstocks: Balancing Responsibility With Urgency
By Bill Castle, Fred Gmitter and Jude Grosser The rootstock development cycle, from creation to eight years in the field to release, is presently about 10 to 15 years. However, if multiple trials are involved, then the time required is increased. The criteria used to advance new selections through the system are commercially based. Rootstocks for juice fruit are assessed …
Rootstocks and Fertilization for Finger Limes
Rootstock selection and fertilization are important for those considering growing finger limes in Florida. University of Florida Institute of Food and Agricultural Sciences horticulturist Tripti Vashisth addressed both of those topics in a recent virtual Finger Lime Symposium. Vashisth concluded that Volkamer lemon, UFR-5 and US-802 rootstocks appear promising for finger limes. She noted that a vigorous rootstock influences tree …
Australia Evaluating Dwarfing Rootstocks
Tahir Khurshid of Australia’s New South Wales Department of Primary Industries (NSW DPI) is leading a project evaluating several overseas rootstocks budded to a range of mandarin and sweet orange varieties. One of the components is evaluating the rootstocks for their dwarfing effect, which will potentially produce small trees for high-density planting systems for the citrus industry. Size-controlling rootstocks have …
Florida’s Top Rootstocks and Varieties
US-942 remained the top citrus rootstock in Florida for the third year in a row, and Valencia SPB-1-14-19 was the top variety. ROOTSTOCKSMore than 1.28 million nursery trees were budded on US-942, according to the Florida Department of Agriculture and Consumer Services’ (FDACS) Citrus Budwood Annual Report for 2020-21. The next 14 most popular rootstocks, with the number of buddings, …
Early Performance of Orange Rootstocks in Commercial Settings
By Ariel Singerman, Stephen H. Futch and Brandon Page This article provides estimates on the performance of different rootstocks grafted with Valencia sweet orange scions in commercial field conditions. These are the first estimates obtained from side-by-side trials that compare the performance of rootstocks developed by two breeding programs: The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) …
Australia to Test UF’s HLB-Tolerant Rootstocks
HLB-tolerant rootstock seeds from the University of Florida (UF) have arrived in Dareton and Bundaberg to be evaluated under Australian conditions. Citrus Australia CEO Nathan Hancock said it’s important that the rootstocks have arrived in Australia well before the Asian citrus psyllid (ACP) and the HLB it spreads. “We need to know if these rootstocks from Florida are going to …