These CRISPR-modified crops don’t count as GMOs

These CRISPR-modified crops don’t count as GMOsAuthor

Increasing crop yields through conventional plant breeding is inefficient – the outcomes are unpredictable and it can take years to decades to create a new strain. On the other hand, powerful genetically modified plant technologies can quickly yield new plant varieties, but their adoption has been controversial. Many consumers and countries have rejected GMO foods even though extensive studies have proved they are safe to consume.

But now a new genome editing technology known as CRISPR may offer a good alternative.

I’m a plant geneticist and one of my top priorities is developing tools to engineer woody plants such as citrus trees that can resist the greening disease, Huanglongbing (HLB), which has devastated these trees around the world. First detected in Florida in 2005, the disease has decimated the state’s US$9 billion citrus crop, leading to a 75 percent decline in its orange production in 2017. Because citrus trees take five to 10 years before they produce fruits, our new technique – which has been nominated by many editors-in-chief as one of the groundbreaking approaches of 2017 that has the potential to change the world – may accelerate the development of non-GMO citrus trees that are HLB-resistant.

You may wonder why the plants we create with our new DNA editing technique are not considered GMO? It’s a good question.

Genetically modified vs. gene edited

Genetically modified refers to plants and animals that have been altered in a way that wouldn’t have arisen naturally through evolution. A very obvious example of this involves transferring a gene from one species to another to endow the organism with a new trait – like pest resistance or drought tolerance.

But in our work, we are not cutting and pasting genes from animals or bacteria into plants. We are using genome editing technologies to introduce new plant traits by directly rewriting the plants’ genetic code.

This is faster and more precise than conventional breeding, is less controversial than GMO techniques, and can shave years or even decades off the time it takes to develop new crop varieties for farmers.

There is also another incentive to opt for using gene editing to create designer crops. On March 28, 2018, U.S. Secretary of Agriculture Sonny Perdue announced that the USDA wouldn’t regulate new plant varieties developed with new technologies like genome editing that would yield plants indistinguishable from those developed through traditional breeding methods. By contrast, a plant that includes a gene or genes from another organism, such as bacteria, is considered a GMO. This is another reason why many researchers and companies prefer using CRISPR in agriculture whenever it is possible.

Changing the plant blueprint

The gene editing tool we use is called CRISPR – which stands for “Clustered Regularly Interspaced Short Palindromic Repeats” – and was adapted from the defense systems of bacteria. These bacterial CRISPR systems have been modified so that scientists like myself can edit the DNA of plants, animals, human cells and microorganisms. This technology can be used in many ways, including to correct genetic errors in humans that cause diseases, to engineer animals bred for disease research, and to create novel genetic variations that can accelerate crop improvement.

To use CRISPR to introduce a useful trait into a crop plant, we need to know the genes that control a particular trait. For instance, previous studies have revealed that a natural plant hormone called gibberellin is essential for plant height. The GA20-ox gene controls the quantity of gibberellin produced in plants. To create a breed of “low mowing frequency” lawn grass, for example, we are editing the DNA – changing the sequence of the DNA that makes up gene – of this plant to reduce the output of the GA20-ox gene in the selected turf grass. With lower gibberellin, the grass won’t grow as high and won’t need to be mowed as often.

The CRISPR system was derived from bacteria. It is made up of two parts: Cas9, a little protein that snips DNA, and an RNA molecule that serves as the template for encoding the new trait in the plant’s DNA.

To use CRISPR in plants, the standard approach is to insert the CRISPR genes that encode the CRISPR-Cas9 “editing machines” into the plant cell’s DNA. When the CRISPR-Cas9 gene is active, it will locate and rewrite the relevant section of the plant genome, creating the new trait.

But this is a catch-22. Because to perform DNA editing with CRISPR/Cas9 you first have to genetically alter the plant with foreign CRISPR genes – this would make it a GMO.

A new strategy for non-GMO crops

For annual crop plants like corn, rice and tomato that complete their life cycles from germination to the production of seeds within one year, the CRISPR genes can be easily eliminated from the edited plants. That’s because some seeds these plants produce do not carry CRISPR genes, just the new traits.

But this problem is much trickier for perennial crop plants that require up to 10 years to reach the stage of flower and seed production. It would take too long to wait for seeds that were free of CRISPR genes.

My team at the University of Connecticut and my collaborators at Nanjing Agricultural UniversityJiangsu Academy of Agricultural SciencesUniversity of FloridaHunan Agricultural University and University of California-San Diego have recently developed a convenient, new technique to use CRISPR to reliably create desirable traits in crop plants without introducing any foreign bacterial genes.

We first engineered a naturally occurring soil microbe, Agrobacterium, with the CRIPSR genes. Then we take young leaf or shoot material from plants and mix them in petri dishes with the bacteria and allow them to incubate together for a couple of days. This gives the bacteria time to infect the cells and deliver the gene editing machinery, which then alters the plant’s genetic code.

In some Agrobacterium infected cells, the Agrobacterium basically serves as a Trojan horse, bringing all the editing tools into the cell, rather than engineering plants to have their own editing machinery. Because the bacterial genes or CRISPR genes do not become part of the plant’s genome in these cells – and just do the work of gene editing – any plants derived from these cells are not considered a GMO.

After a couple of days, we can cultivate plants from the edited plant cells. Then it take several weeks or months to grow an edited plant that could be planted on a farm. The hard part is figuring out which plants are successfully modified. But we have a solution to this problem too and have developed a method that takes only two weeks to identify the edited plants.

One significant difference between editing plants versus human cells is that we are not as concerned about editing typos. In humans, such errors could cause disease, but off-target mutations in plants are not a serious concern. A number of published studies reported low to negligible off-target activity observed in plants when compared to animal systems.

Also, before distributing any plants to farmers for planting in their field, the edited plants will be carefully evaluated for obvious defects in growth and development or their responses to drought, extreme temperatures, disease and insect attacks. Further, DNA sequencing of edited plants once they have been developed can easily identify any significant undesirable off-target mutations.

In addition to citrus, our technology should be applicable in most perennial crop plants such as apple, sugarcane, grape, pear, banana, poplar, pine, eucalyptus and some annual crop plants such as strawberry, potato and sweet potato that are propagated without using seeds.

We also see a role for genome editing technologies in many other plants used in the agricultural, horticultural and forestry industries. For example, we are creating lawn grass varieties that require less fertilizer and water. I bet you would like that too.

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Florida Land Values Strong Thanks to Rising Economy

Improving economic conditions are showing up in the results of the seventh edition of the “Lay of the Land Market Report.” The report provides an accounting of verified land sales from 2017. The update was released in April during the annual Lay of the Land Conference held at Champions Gate near Orlando.

Dean Saunders, owner of Lakeland-based Coldwell Banker Commercial Saunders Real Estate, publishes the report and hosts the conference. He said the real estate market is firing on all cylinders with elevated activity in all sectors of the market.

“Overall, the residential land market in Florida is very strong as a result of the improving economy, combined with the continued influx of almost 1,000 people per day to the state,” Saunders said. “As demand for residential development land increases, sales of agriculture land in the paths of progress increase. With the capital earned from selling land for high development prices, sellers are reinvesting in other rural agriculture land.”

The heart of residential growth is occurring along the I-4 corridor from Tampa to Daytona Beach. Jerry Parrish, Chief Economist for the Florida Chamber of Commerce, gave some perspective on the growth during the conference, noting that from Jan. 1 to April 6, 83,524 people had moved into Florida, and the state’s adjusted gross income grew by $2 billion. People from New York, New Jersey, Pennsylvania, Ohio, and Connecticut (in that order) lead the migration into the state.

Treasure Coast
The real estate market in the Treasure Coast (Indian River, St. Lucie, Brevard, Martin, and Okeechobee counties) is hot. In Indian River County, 5-acre ranchette lots sold at the bottom of the market in the $10,000 to $12,000 range. According to the report, prices are strongest in Martin County with a few sales in the $25,000 to $50,000 range for home sites of approximately 5 acres.

The region’s citrus industry continues its tailspin in the face of HLB and the devastation brought on by Hurricane Irma.

Grapefruit production estimates continue to fall with the May USDA forecast at less than four million boxes.

Citrus groves that are no longer productive are selling in the $3,500 to $5,300 per acre range, while better producing groves are fetching $5,000 to $8,000 per acre.

Other Citrus Lands
Prices for citrus land ranged widely in 2017 in other production areas, according to the report (Polk, DeSoto, Hardee, Hillsborough, Manatee, Highlands, Lake, Collier, and Hendry counties).

Typical buyers were skilled and seasoned growers. While the report didn’t account for sales for residential or commercial development, groves in the path of development are highly desirable. There is demand for higher-quality, better-producing citrus groves. Marginal groves are in demand where alternative crops are desirable.

Approximately 10,994 gross acres and 9,252 net-tree acres were included in 90 selected 2017 sales in this area totaling almost $70 million. The sale prices ranged between $2,500 and $15,000 per gross acre. Net-tree citrus-acre sales ranged between $2,500 and $17,067 per acre. The average for the sales was $6,278 per gross acre and $7,461 per net-tree acre. The midpoint was $6,688 per net-tree acre. The 2017 price per net-tree acre and price per gross acre are both approximately 4.5% less than in 2016. The volume of acreage sold is approximately 5.3% less than in 2016.

Strawberry Sales
In Hillsborough County, there was some activity with seven sales that comprised 90 gross acres. The price per gross acre ranged from $10,417 to $33,500 for the seven farms sold.

There were three additional sales of farmland for transitional uses in southeastern Hillsborough. Two of these farms were sold for solar farms: one for $18,278 per gross acre and $22,262 per upland acre and the other for $30,771 per gross acre and $31,518 per upland acre. Another sale for high-density residential went for $77,778 per gross and upland acre.

There were two sales in the Plant City and Dover growing areas. A tract that went from strawberry farmland to a solar farm sold for $23,936 per gross acre and $34,622 per upland acre. Another strawberry farm that went to commercial development sold for $125,000 per gross and upland acre.

Farmland sales in Hillsborough reflect continual market shifts into transitional uses. Pressure from urbanization has continued to creep into farming country.

Central Florida Sales
According to the report, there were five notable sales of vegetable farmland in 2017. Quality irrigation land prices remained stable in the area.

Okeechobee County farm sales ranged from $4,849 per upland acre, where conversion from citrus was required, to $7,080 per upland acre for a turnkey farming operation.

The largest farming purchase was in western Manatee County for $6,169 per upland acre. In Polk, Highlands, Hardee, and Okeechobee counties, farmland prices ranging between $5,000 and $7,500 per acre were prevalent.

Institutional investors continue to seek out grower owners willing to sell land for lease-back arrangements on the property.

Everglades Ag Area
Sales of property in the Everglades Ag Area (EAA) were down in 2017. While prices have been increasing in the region, there were only two notable sales last year. One sale was within Palm Beach County and the other one was in southern Glades County. Lands in the central region of the EAA, within Palm Beach County, are the most desirable with prices exceeding $11,000 per acre.

Demand for agricultural lands within the EAA has been high the last few years, but the market’s inventory remains tight.

Residential Development
The land values report tracked residential sales in 17 counties in Florida. Development continues to heat up in the state, particularly around major population centers of Central Florida. Fifteen of the 17 counties showed moderate-to-high finished lot sales activity.

The price for useable, residential land was up 19%, averaging $56,672 per acre. Land values ranged from $223,208 per acre in Martin County to $18,831 in St. Lucie County.

CRDF Rootstock Field Day

The CRDF Rootstock Field Day will begin at 9:30 a.m. The field trial at Peace River Packing Company consists of one common Valencia clone on the following rootstocks: US-812, US-897, US-942, UFR-2, UFR-3, UFR-4, UFR-16, and Carrizo. This site is one of the large multi-location, replicated, three year old trials of Valencia on six candidate HLB-tolerant rootstocks compared to standard trees on US-812. Other locations are on the Ridge (Blumberg) and Flatwoods (LaBelle). Horticultural performance will be discussed along with the distribution of summary data and maps. Attendees will be free to explore the location. Drs. Jude Grosser and Kim Bowman will be speaking. There will be one CEU in crop management for CCAs. For more information, please contact Chris Oswalt, 863-519-1052, wcoswalt@ufl.edu

The Status of Orange Juice Supply

The Status of Orange Juice Supply

orange juice

By Marcos Fava Neves

The newest estimate from the U.S. Department of Agriculture for the 2017–18 season shows Florida with only 46 million boxes of oranges coming from 50 million trees, which represents 33 percent lower production than the 2016–17 season. High droppage and small fruits are also expected.

Rabobank estimates Florida’s juice production at 235,000 tons [frozen concentrated orange juice (FCOJ) equivalent] in 2017–18 and 250,000 tons in 2018–19. Total output in 2016–17 was 390,000 tons. The orange juice chain is fortunate that Brazil has 385 million boxes and is able to supply the world markets. However, if a huge price increase occurs, that could further damage juice consumption.

BRAZILIAN EXPORTS UP
Since the beginning of the current season, exports from Brazil are 25 percent higher in volume and 32 percent higher in income. Because of Hurricane Irma’s damage to Florida citrus, approximately 30 million boxes now have to be crushed and diverted to the United States, complicating logistics.

Rain came back in Brazil, but extreme weather created problems for the first bloom. The effects on the 2018–19 crop are unknown at this point, but will be announced on May 10. Rabobank estimates Brazilian 2017–18 production at 1.2 million tons of FCOJ, including approximately 335 million boxes for crushing and 50 million for the internal market. Rabobank’s 2018–19 projection of 950,000 tons is a little bit more conservative. The estimate also shows a demand decline of 4 percent per year in the next two years.

BIG BRAZILIAN CROP
The new Fundecitrus estimate published on Dec. 11 for the current crop in the Brazilian orange belt is 385 million boxes, coming from roughly 175 million trees. It is 57 percent higher than last year, nearly 3 percent larger than the last estimate, and 5.69 percent greater than the initial estimate published in May.

Fruits have bigger weight due to above-average rains at the beginning of the crop and better treatment of the orchards. As of mid-December, early-season oranges are almost all harvested, mid-season oranges are 90 percent picked, and late-season oranges are approximately 60 percent harvested. Factories are working at full capacity to process this large crop.

MARKET OUTLOOK
Some recovery of the very low and dangerous juice stock levels will be seen, but we will still be dependent on a good 2018–19 crop to bring normality back. Current prices are good for farmers.

I expect juice prices in Europe to be near $2,400 to $2,500 (bulk FCOJ price per metric ton) for the coming months. If Brazil’s current crop (July to June) was as small as last year’s crop, combined with the problems of the Florida crop (October to September), there would be a huge shortage, causing terrible problems for the world’s orange juice supply. With Brazil’s large expected production, fortunately this is not the case.

Marcos Fava Neves is a professor at the University of São Paulo (Brazil), international adjunct professor at Purdue University (Indiana) and author of “The Future of Food Business” (World Scientific, 2014).

* Courtesy of SE AgNet Media

Citrus officials cleared to use bactericides another year

“It’s a good thing we got it so we can re-evaluate it,” said John Barben, an Avon Park grower and president of Florida Citrus Mutual in Bartow, the growers’ trade group. “It’s a tool in our toolbox, and we need all the tools we can get.”

The EPA had long approved use of the three bactericides — two brands of oxytetracycline and a streptomycin compound — for stone fruit and other crops but not for citrus. Research sponsored by the Lake Alfred-based Citrus Research and Development Foundation Inc., the chief scientific agency in the fight against greening, showed the bactericides could diminish the effects of greening, including increased levels of pre-harvest fruit drop and smaller fruit.

In March 2016, the agency approved a one-year “Section 18” special-use exemption for citrus. The EPA on Jan. 17 approved a third year of the exemption.

“I applaud the EPA’s decision to once again allow the use of antimicrobials on diseased citrus trees,” said U.S. Sen. Marco Rubio in a press statement following the decision’s announcement. “Our iconic citrus industry has long battled greening, and especially following the devastation of Hurricane Irma, this announcement is greatly appreciated. However, Florida agriculture is still in desperate need of disaster relief to help replace lost trees, rehabilitate flooded groves, and assist beleaguered farmers. I continue to work with my colleagues in Congress to secure this much-needed support for Florida farmers.”

Barben said he and many other citrus growers began using the bactericides right after the 2016 announcement. He said he plans to continue using the bactericides this season but at reduced rates because of the economic impact from the fruit lost to Irma.

“It’s an expensive spray,” he said. “These days you have to be careful what you put out there. You have to consider how much bang for the buck you get.”

Harold Browning, the chief operating officer at the Citrus Research Foundation, welcomed the EPA announcement, but he acknowledged the scientific data on the bactericides’ effectiveness is “noisy,” meaning there’s conflicting data.

Irma has complicated the ongoing effort to assess their effectiveness, he said. That’s because the storm dramatically reduced citrus tree yields, the number of fruit harvested per tree, one of the chief bactericide benefits.

Barben saw a 12 percent decline in the harvest of early and mid-season orange varieties, picked November to March, this season, he said. But he counted about one box of fruit per tree on the ground because of Irma, which would have meant an increased harvest but for the storm.

There was some good news about bactericides from Tom Jerkins, president of Premier Citrus in Vero Beach, one of the state’s largest growers, Browning said.

In a presentation earlier this week at the Florida Citrus Show in Fort Pierce, Jerkins reported a 15 percent yield increase in his 2016-17 crop of Valencia oranges, picked from March to June, he said. He had been using bactericides since 2016.

The increase is similar to results in some other studies, Browning said.

“There seems to be come convergence” on the 15 percent increase, he said.

In an email to The Ledger, Jerkins declined to make the presentation available. He could not be reached on Friday to comment.

EPA officials have indicated they will have a decision on full approval of the bactericides for citrus in the first half of this year, Browning said. However, that date could be extended.

Greening is a bacterial disease that eventually kills a citrus tree. Infected trees produce fewer and smaller fruit, and they tend to drop what fruit they do produce before harvest.

Kevin Bouffard can be reached at kevin.bouffard@theledger.com or at 863-401-6980.

Express Lanes Open to Find Latest Citrus Variety Trends

 

The FAST TRACK model was developed as a means of making promising experimental UF/IFAS fresh citrus varieties available to nurseries and growers for trial and possible expedited commercial production. This innovative program engages growers and nurseries much earlier in the process, enabling participants to gain experience with the selections and make determinations of horticultural characteristics and performance as well as market acceptance of the final product.

To date, three suites of FAST TRACK citrus varieties have been introduced to the Florida citrus industry, resulting in small-scale diverse trial sites scattered throughout the traditional citrus production areas, as well as the northern border counties.

The challenges are:
• Nurseries are having to rapidly learn how to grow these selections. Each behaves a little differently in the nursery and the process entails much more than budding trees for rapid increase of plant material.
• Trees are planted in a wide range of locations and conditions. Soil, water, temperature, and other variables factor into tree performance.
• A range of rootstocks were used with each scion. Thus far, through three suites of FAST TRACK releases, there are 127 scion/rootstock combinations in the field. Some were planted quite extensively, and some were planted in very small quantities.
• The trials are not of a scientific design. Growers ordered the combinations they wanted in the quantities desired. Grove layout and design differs from farm to farm, as do production practices.

Mind Your Material
Diversity is both a friend and foe in the evaluation of FAST TRACK selections. The program is designed to enable growers to plant new material and make their own determination of performance and marketability. Trial sites are for grower observations not research-oriented data collection.

Notwithstanding, it also is important that we make every effort possible to leverage these diverse trial sites to inform future planting decisions. Growers wishing to plant these selections in the future will have the reasonable expectation that information was compiled during the trial stage and early days of commercial production. Some FAST TRACK selections will not move into commercial production. Some will fail, while others may have niche market or dooryard potential. However, growers will need some basis for planting those FAST TRACK selections that prove to have commercial utility.

Observe and Report
The primary source of information related to FAST TRACK selections originates from trial report forms. When executing a FAST TRACK Tier I grower agreement, growers commit to periodically completing trial report forms and sharing information related to their trial plantings. Tier II growers share this obligation. However, after some discussion, New Varieties Development & Management Corp. (NVDMC)Florida Foundation Seed Producers Inc., and the UF/IFAS Plant Improvement team concluded there is added value in visiting the FAST TRACK trial sites, making observations about tree performance/health and production. When appropriate, it would be desirable to record information about fruit characteristics, productivity, and/or fruit quality.

After a considerable search, the NVDMC Board of Directors elected to contract with a crop scouting and monitoring company. If you are a FAST TRACK grower with trees from Suites I-III, expect a visit this season from On Point Ag. Growers will be contacted in advance, and an appointment will be established for a trial site visit. Grove maps are most helpful for these visits, as are any notes or records related to grove care, pruning, nutrition, bloom, fruit set, disorders, tree health, stress, etc. The field scout will take some measurements, snap a few photos, and ask a few questions (having an involved party present to answer questions is most appreciated). Everything gathered will be strictly confidential and will only be shared in a compiled general format.

No information from these visits will be associated with any particular grower. It is hoped as more visits are made, trends will begin to emerge that may prove helpful to growers, breeders, nurseries, and NVDMC.

This project may reveal that certain selections perform better in specific locations or conditions. We may learn that certain scion/rootstock combinations are superior and others are to be avoided. We may end up with more questions than answers or a general idea of what needs to be explored more extensively. This is but the first step in a process to glean meaningful information from small trial sites with tremendous geographic, horticultural, and operational diversity.

If you have FAST TRACK trees and would like to contact On Point directly, use onpointag@live.com to get on the calendar.

Do I Hear a Bingo?
‘Bingo’ is now in FAST TRACK Tier I trials and Tier II production. Though trees are still quite young, it is time to gather growers and nurseries (involved with this variety) for an exchange of information. NVDMC will host a ‘Bingo’ discussion opportunity at the UF/IFAS Citrus Research and Education Center on Feb. 20.

The last UF/IFAS variety display of the season will be held from 10:00 a.m. to 11:30 a.m. The ‘Bingo’ discussion is for registered growers and nurseries only and will take place in the Ben Hill Griffin Auditorium immediately following the display. This will be a working lunch. Box lunches are available for $10. Please RSVP to Lucy Nieves (lucy.nieves@ffva.com) and let her know if you would like a lunch.

 

UF/IFAS, Tropicana test promising new citrus varieties for greening tolerance

Grafted orange trees showcased at the 100th anniversary of the UF/IFAS Citrus Research and Education Center may give the state’s citrus growers new reason to hope the industry can cope with the citrus greening crisis, UF/IFAS researchers say.

University of Florida scientists and Tropicana are teaming up to test promising new UF/IFAS-bred citrus varieties for greening tolerance and better-tasting juice. Tolerance means trees are infected and remain infected, but they still perform adequately to make a profit, UF/IFAS researchers say. Resistance means the trees fight off the infection – either reducing the infection to a very low level or getting rid of it completely.

“I’ve been out to the site twice in the past year and some of the rootstock-scion combinations just jump out at you with the lush green foliage and, more importantly, a large number of nice-sized fruit,” said UF/IFAS CREC Director Michael Rogers.

“What’s more, there are multiple large plots for each rootstock combination that allow us to really get a good idea of how these trees are holding up under greening,” Rogers said. Greening, also known as huanglongbing, or HLB, has impacted more than 80 percent of Florida’s citrus trees, according to UF/IFAS research. Rogers added: “From what I’ve seen, we’ve got some reasonably tolerant scion/rootstock combinations that growers should be taking a look at as short-term solutions to living with greening until true HLB-resistant trees are developed.”

Tropicana leases 14.5 acres for testing new selections including UF/IFAS-developed citrus cultivars and rootstocks in a commercial grove about 4 miles from the UF/IFAS Citrus Research and Education Center, said Jude Grosser, a UF/IFAS professor of horticultural sciences and a faculty member at CREC.  UF/IFAS researchers have a long history of working with Tropicana, Grosser said.

“This trial is providing strong evidence that the combination of improved scion genetics, improved rootstock genetics and optimized nutrition programs is the ticket for the immediate future,” Grosser said.

For example, the combination of UF sweet orange OLL-8 cultivar on UFR-4 rootstock looks exceptional for both yield and tree health, Grosser said.

“These clones are a good immediate-term solution to help us until resistant clones are available,” he said. “We are continuing to screen rootstock hybrids for HLB tolerance that can be transmitted to a grafted scion. So far, we have screened more than 10,000 hybrids, and we have identified a few truly promising selections. Citrus breeding is a continuum – we are constantly building on previous progress.”

The relationship between Tropicana and UF/IFAS goes back many years.

“They became interested in our sweet orange improvement work through research interactions and presentations made at trade shows and seminars,” Grosser said. “We began sending them fruit samples from promising selections for sensory analysis.”

Rocco Simonetta, who’s now retired from Tropicana, spearheaded the UF/IFAS-Tropicana Project Field trials – with the first two trials focusing primarily on sweet orange selections in our pipeline that might be good additions to their Not-From-Concentrate (NFC) portfolio, Grosser said. The current trial focuses more on the addition of new rootstocks as necessary to deal with HLB.

Cheryl Nagle of Tropicana worked with Simonetta at the beginning, and she passionately followed up on building the relationship after Rocco’s retirement, Grosser said. She now is in charge of the trials.

“This is all truly a team effort,” he said.

Tropicana and UF/IFAS started their collaboration on the current project in June 2013, said Allison Drown, who manages the grove near Lake Alfred for Tropicana.

“We monitor tree health, fruit yield and juice quality,” Drown said.

Grosser commended Tropicana’s interest in testing many new UF/IFAS selections in their citrus trial.

“Tropicana has taken no shortcuts – they are employing state-of-the-art management of the trial,” said Grosser, who led a tour of the private groves at the Nov. 29 centennial celebration of the UF/IFAS CREC.

Tropicana and UF/IFAS breeders started with about 30 scion selections — or descendants of other varieties, Grosser said, but because of citrus greening, Tropicana decided to look at new and improved rootstocks as well, he said.

Citrus scientists use traditional plant grafting to put together combinations of new scions and rootstocks created in the breeding program.

In plant grafting, scientists call the upper part of the plant the scion, while the lower part is the rootstock. Grosser said he sees promise in about half a dozen scion-rootstock combinations in this trial, most of which are releases from UF/IFAS CREC.

Based on UF/IFAS data, UF/IFAS citrus breeders suggest new oranges, orange-like hybrids and rootstocks from the CREC citrus improvement program that they think Tropicana might be interested in for future use in its business, Grosser said.

“With our advice, Tropicana makes the final decisions on which scions and rootstocks are in the trial, and also the decisions on how to manage the trees,” he said. “We are currently working with Tropicana to develop a plan where we can work together to get good yield data this year.”