Unnatural Selection Significant In Evolution Of Citrus

Humorous take on the theory of evolution for citrusSeveral decades back, UF/IFAS and USDA breeding programs were working in earnest to develop and identify superior breeding stock and ultimately release scion and rootstock varieties with superior traits. The pace of development, evaluation, and release was quite different than today. Many growers were satisfied with the varieties they were growing, resulting in limited demand for new material and lackluster support for variety development efforts. Hamlin, Pineapple, and Valencia served Florida’s processing needs just fine, and Florida dominated the fresh grapefruit and specialty markets. Breeders were pushing varieties through the process.

The dawn of the new century changed everything. HLB arrived, necessitating a reevaluation of all aspects of citrus production. Whether fresh or processed, all growers were under pressure to innovate. Following on the heels of successful Spanish imports, California invested heavily in seedless easy peel clementine and mandarin varieties, changing the American fresh fruit landscape. Suddenly, Florida needed scions, rootstocks, and combinations capable of withstanding HLB, and hopefully, offering new and marketable traits. Working in concert with the breeding programs, New Varieties Development & Management Corp. (NVDMC) was formed to assist in bringing focus to the process, integrating industry involvement, providing targeted financial support for development projects, and breaking down barriers to success.

Florida’s citrus breeding programs are globally recognized for their productivity, strong pipeline, and future capabilities. Fresh and processed varieties and selections of immediate or potential commercial value are being released and trialed with regularity. There is certainly momentum behind the variety development machine. The next layer of the onion presents unique challenges for Florida, in light of the perfect storm of competitive and disease pressure. With so many variety options, it poses the question: How much is enough? Let’s explore the challenges.

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Processed Varieties

With more than a half dozen new processed orange selections recently released by UF/IFAS and offered for commercialization through Florida Foundation Seed Producers Inc. (FFSP), and more in the pipeline, what are the appropriate criteria for release? Once we have multiple varieties in each maturity window, have we reached a saturation point?

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Plateful of specialty tangerine variety samples.

Interest and demand are rising for new specialty citrus selections.
Photo by Peter Chaires

Clearly, not all new releases will be commercially successful. Nurseries are being licensed for production, and budwood reports show increased production of the new selections. Growers are placing orders to plant trial quantities in hopes of picking a winner. Growers press the breeders and nurseries for advice on scion-rootstock combinations, but little hard data are available. There is great hesitancy to offer advice on these issues, as the extended head may end up on a chopping block. Many innovative growers are planting rootstock/scion combination trials, and much will be gleaned from these efforts. The Citrus Research and Development Foundation (CRDF) is committing resources to study disease tolerance and resistance, and supporting some research in genetic improvements of such traits. Information vital to planting decisions (for processed orange growers) will be derived from private and public efforts. Clearly, greater genetic diversity available to industry enhances the chance of success, but how much is enough? Presently, demand for variety options appears to exceed supply. Nurseries and growers are demonstrating a hunger for options. At some point, DPI and nursery capacity will become a new constraint in the process, and nurseries and growers may cease looking to the “new” and rather focus more on existing options that have yet to be fully explored.

Some of the most tolerant orange selections may not be considered true “orange” under the federal standard of identity. These selections are complex hybrids that have all of the desirable characteristics of an orange, and are indistinguishable from an orange, even by trained taste panels. Today, a breeder can recreate a sweet orange from its ancestral lineage of pummelo and mandarin, yet this would not necessarily meet the federal standard of identity for a sweet orange. Consequently, it might not be accepted by processors and thus by the growers supplying them. Seemingly, if these selections continue to perform well in the field, this issue will get resolved. Once it is, this will present a whole new line of options for nurseries and growers.

The other foundational value of a successful breeding program is the development of varieties with superior traits (yield, color, flavor, etc.). Though today’s environment necessitates that disease tolerance be a key component of the selection process, Florida must maintain its commitment to the development of material with superior traits. Continuous improvement is what built this industry. In days past, much of this came from observed natural mutations, but each improvement elevated the industry and improved our product and profitability. Well supported breeding efforts accelerate this process. Though it might seem unnecessary to some to continue breeding in the face of HLB, it is vital to Florida’s future. HLB will be defeated one day and breeding programs cannot be turned on and off like a light switch. Grower demand and supply constraints will ultimately dictate release decisions, but the research must continue.

Fresh Selections And Varieties

The challenge of multiple varieties within each harvest window will be exacerbated in the fresh sector. Though many of Florida’s packinghouses are reliant on grapefruit and oranges for survival, specialty selections have garnered the most attention at variety displays and FAST TRACK registrations. Perhaps this is reflective of specialty having the most immediate need. Perhaps it mirrors the well-known consumer trends. Producers who have traditionally grown specialty varieties have flocked to new mandarin options, but so have grapefruit growers and those in the processed orange sector. Many small growers struggling to remain competitive are looking to high-value specialty crops as an alternative. Thus far, Florida specialty releases have targeted the September through December window. Eventually, Florida will have multiple specialty selections with similar traits and overlapping maturities.

Florida red grapefruit samples

Varieties with superior traits are and should remain a priority.
Photo by Peter Chaires

Ultimately, we will see more releases in the post-December window. Disease tolerance and yield will assist with natural selection and market acceptance will certainly cause the cream to rise to the top. Critical mass might be a more significant issue for specialty varieties than any other category. While some marketers thrive on differentiation through niche, high-value markets, the vast majority of Florida specialty growers will be reliant on the Florida industry achieving critical mass with mainstream specialty selections. As hundreds of growers are experimenting with new selections and rootstocks, nurseries will be challenged to remain on the cutting edge, anticipating the winning formula and having material available for the next order. Eventually there will be new mainstream Florida specialty varieties that have proven market acceptance and sufficient tolerance to remain productive. The rest of the selections — each with unique attributes — will provide opportunities for differentiation and exclusive markets.

Recognizing this reality, one solution is for breeding programs to lift their foot off the gas somewhat, and focus more on field evaluation of existing material and less on making new crosses. Another approach is a shift to more HLB-tolerant breeding parents, enhancing the likelihood of producing tolerant progeny. In the interim, efforts are under way to better understand the interaction of genetics with nutrition. Continued progress optimizing nutrition to reduce HLB symptoms might expand the number of acceptable selections.

One thing is clear, new variety options will continue to populate the pipeline, and NVDMC, UF/IFAS, FFSP, and USDA-ARS will look to nursery and grower demand to dictate the flow. Grapefruit and orange varieties typically have a longer maturity window than specialty fruit, and it will take fewer quality selections to meet the demand. As more tolerant grapefruit, orange, and rootstock combinations, teamed with crop protection and psyllid control, improve productivity and profitability, it will again come down to those varieties with the most marketable traits. Today’s consumers are more demanding of superior quality, and new flavors and colors are generally valued. Disease tolerance and marketable traits are the focus of today’s breeding efforts. While Florida can’t breed its way out of the short-term crisis, breeding can certainly fuel the future.

Though this might seem like a case of unnatural selection, generally speaking, these are good problems to have. Florida may have to struggle through some confusion and frustration as this sorts itself out, but the end-game will be a more diverse and sustainable industry better suited to meet consumer demand. Until then, brace yourself for more choices. As highlighted in my article last month, information from this process must ultimately be gathered, deciphered, and shared.

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