drought

Rootstocks Show Drought Tolerance in Brazil

Daniel CooperBrazil, Research, Rootstocks

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 …

SuperSour

More SuperSour Rootstocks Under Study

Daniel CooperRootstocks

“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 …

ReMedium TI®

Rootstocks and OTC

Daniel CooperHLB Management, Rootstocks

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

CITRUS NURSERY SOURCE: A Day of Learning About New Rootstocks and Varieties

Daniel CooperCitrus Nursery Source, Rootstocks, 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 …

field

Rootstocks and More Showcased at Field Day

Daniel CooperEvents, Rootstocks, Varieties

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

Josh McGillCold Hardy, freeze, Rootstocks

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

Josh McGillNutrition, Rootstocks, Varieties

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

Josh McGillNutrition, 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

Josh McGillRootstocks, Tip of the Week

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

Josh McGillInternational, Research, Rootstocks

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

Josh McGillHLB Management, Research, Rootstocks

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

Josh McGillRootstocks, Tip of the Week

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

Josh McGillLimes, Nutrition, Rootstocks

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

Josh McGillInternational, Research, 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 …

citrus rootstock

Florida’s Top Rootstocks and Varieties

Ernie NeffRootstocks, 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

Tacy CalliesEconomics, Rootstocks

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

Ernie NeffRootstocks

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 …

SuperSour

Research on Rootstocks: More Than HLB

Ernie NeffRootstocks

Plant breeders Fred Gmitter and Jude Grosser report on their efforts to develop rootstocks that perform well in Florida from several perspectives. In addition to seeking tolerance to HLB, they are working on rootstocks that might control tree size, deal with other diseases and pests and perform in a range of soils. Gmitter and Grosser are University of Florida Institute …

Rootstocks US-812, US-942 Hold Promise

Ernie NeffRootstocks

The rootstocks US-812 and US-942 seemed to offer promise in early economic performance evaluations that economist Ariel Singerman discussed at the 2021 Citrus Expo. Singerman is a University of Florida Institute of Food and Agricultural Sciences Extension economist at the Citrus Research and Education Center in Lake Alfred. Singerman analyzed yield and economic performance of rootstocks in commercial settings during …

The Secret Ingredient of Developing New Citrus Rootstocks

Tacy CalliesCitrus, Rootstocks

By Bill Castle Creation, evaluation, release and commercial acceptance are dynamic, interactive activities that together constitute new rootstock development. Underpinning each of them is a commonly overlooked and rarely mentioned activity, professional judgment. Yet, it is something everyone has and recognizes as getting better with time and experience. It is a skill developed and refined over time from knowledge of …