Stay Current With Research on Rootstocks

Jim Rogers Rootstocks, 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

Jim Rogers International, 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

Jim Rogers HLB 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

Jim Rogers Rootstocks, 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

Jim Rogers Limes, 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 …

Progress With SuperSour Rootstock Trials

Jim Rogers Research, Rootstocks

By Kim D. Bowman The breeding of new citrus rootstocks is not an endeavor for the impatient. Two of the most popular rootstocks in Florida, US-942 and US-812, each were included in field evaluation for more than 20 years before the U.S. Department of Agriculture (USDA) released them for commercial use. In these cases, the time invested in thorough testing …

Australia Evaluating Dwarfing Rootstocks

Jim Rogers International, 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 …

CRDF Seeks Growers for Rootstock Trials

Jim Rogers CRDF, Rootstocks

The Citrus Research and Development Foundation (CRDF) is seeking Florida citrus growers on the Ridge and in the flatwoods of Southwest Florida to potentially be grower-cooperators in large rootstock trials. The goal of the new trials is to identify plant material with the traits needed by growers to realize the highest possible pound solids per acre and increase tree viability …

Consistency Is Key in Rootstock Field Trials

Jim Rogers Rootstocks, Tip of the Week

By Bill Castle Today, at least three things seem to be true about Florida citrus rootstock field trials: There is an unprecedented number of them underway or soon to be planted. The sponsors are many, including the University of Florida, U.S. Department of Agriculture, Citrus Research and Development Foundation, Citrus Research and Field Trial Foundation and the Multi-Agency Coordination Group. …

citrus rootstock

Florida’s Top Rootstocks and Varieties

Ernie Neff Rootstocks, 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, …

Which Rootstock to Select

Tacy Callies Rootstocks, Tip of the Week

Valencia trees on high-vigor (left) and low-vigor (right) inducing rootstocks in a Central Ridge field trial. Note the higher yield efficiency of the smaller trees on the right and the leaning of these trees due to Hurricane Irma. By Ute Albrecht Rootstock selection is critical for longevity and productivity of a grove. The decision should be based on compatibility with …

Early Performance of Orange Rootstocks in Commercial Settings

Tacy Callies Economics, 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) …

Graft Compatibility of New Scion−Rootstock Combinations

Tacy Callies Rootstocks

By Ute Albrecht, Bo Meyering, José Chaparro and Kim D. Bowman Grafting is an ancient horticultural technique. There is evidence of citrus grafting in the Roman era dating back to the fifth century. In western Europe, grafting was regularly practiced in the 16th and 17th centuries when citrus was grown as an exotic ornamental in containers in orangeries. In Florida, …

Australia to Test UF’s HLB-Tolerant Rootstocks

Ernie Neff 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 …

Heavy Fruit Loads in Rootstock Trials

Ernie Neff Rootstocks

Heavy fruit loads have created a problem for Owari satsuma rootstock trials in Valdosta, University of Georgia Extension agent and Lowndes County Extension Coordinator Jake Price reported recently. “It has been a struggle the last month or so to keep fruit off the ground because of the heavy fruit load,” says Price. “Fruit touching the ground will rot and fall …

Research on Rootstocks: More Than HLB

Ernie Neff Rootstocks

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 Neff Rootstocks

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 …

How to Work With UF/IFAS for a Rootstock Trial

Tacy Callies Rootstocks, Tip of the Week

By Bill Castle The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center (CREC) plant improvement team has long been engaged in field research to evaluate new scions and rootstocks. That effort continues and has involved trials on public and private property. While public sites are valuable, they are limited in number. Thus, most …

Maximizing Rootstock Seed Production

Tacy Callies Seed

By Fernando Alferez, Deived Uilian de Carvalho, Daniel Boakye, Tim Gast and Manjul Dutt Endemic HLB in Florida has provoked increased pressure to replant and reset infected groves. This has resulted in concern from citrus growers and nursery operators about seed availability for the most popular rootstocks in the state. In the past, all rootstock fruit (both early and late …

Indian River Millennium Block Shows Rootstock Effects

Tacy Callies Rootstocks

By Rhuanito S. Ferrarezi, J. Martin Zapien-Macias, Mac Hossain, Tom James, Ronald D. Cave, Peter Spyke, William S. Castle, Jude W. Grosser, Fred Gmitter and Ed Stover In the last decade, huanglongbing (HLB) has reduced production of Florida grapefruit by 75%, mandarin by 78% and sweet orange by 52%. This decrease is significant for the Indian River District, which produces …