Pictured is a Central Florida ‘Bingo’ planting this past fall. ‘Bingo’ has been released for commercial planting (a license is required) and growers are interested in sharing their information and experiences to accelerate the group up the learning curve.
Photo courtesy of Peace River Packing
Recent industry discussions related to plant improvement and evaluation of new citrus material have highlighted the need for a process with more scientific design than FAST TRACK (an expedited process developed for UF/IFAS fresh selections) and faster than traditional replicated field trials. While there is value in maintaining a process to flow new selections to nurseries and growers very early in the process for observation and experiential learning, the high variability of conditions, production practices, and rootstock/scion combinations makes it difficult to glean and compile valuable information for the next generation of growers.
Most FAST TRACK growers will share their observations, but few possess the willingness and/or skill set to collect and submit uniform data from a designed trial. Long-term trials produce the rich data the industry craves, but Florida growers need answers sooner than later.
The typical Florida small-scale, private trial provides a subjective evaluation of tree health, crop load, and fruit marketability. Some growers document their observations; other growers share information conversationally. Readers have questioned how other production areas are evaluating new citrus material.
Some global production areas share Florida’s struggle with HLB, and others continue to operate in a pre-HLB environment knowing that its arrival looms on the horizon. I contacted entities in other citrus production areas engaged in trial and evaluation to specify what information they collect and document. This exercise didn’t illuminate a magic path forward, but perhaps it will further inform our dialogue.
Fresh Fruit Scion Varieties
- Below is a compilation of factors that comprise the focus of private and public evaluations:
- Trueness to type
- Harvesting time and holding time on tree
- Some, but not all, include trunk diameter and tree size — to guide density decisions.
- Fruit size and range, including the percent in each marketable size range. Shape: height, diameter
- Fruit weight
- Tree vigor: low, intermediate; growth habit
- When relevant, climate suitability
- Performance on a range of rootstocks
- Determine whether special cropping measures are necessary
- Disease susceptibility
- Flavor (subjective appeal, plus brix/acid and ratio)
- Including after storage. This flushes out off-flavors that may develop
- Pulp texture and color
- Juice content
- Peel color. Does it naturally develop? If not, does it degreen or will it color after harvest with additional cooling?
- Aroma when peeling or cutting. Focus on oils. Pleasant, indifferent, unpleasant
- Peel disorders and texture, including those that will cause spoilage and those that would diminish packout or, worse yet, be a market access issue.
- Fruit firmness. Easy peelers tend to be called “soft citrus” for a reason, but they can’t be so soft they don’t make it to market or require additional, expensive packaging. This applies to both export and domestic shipments.
- Included in firmness is whether the fruit must be clipped.
- For fruit that would most likely be peeled — how easy is it to start and complete the peeling process?
- Seeds. There are still markets in the world that will accept a fruit with superior flavor — with seeds — but these markets are limited. This measure typically includes percent with 0 seeds and percent with 1-2, 3-5, 5-10, >10.
- Fruit sample size ranged from 10 to 50 per tree. Most measurements start in year three. When volume permits, this is done in the beginning, middle, and end of the maturity range.
- For fresh fruit, the respondents also were asked how large trial plantings need to be in order to yield beneficial results. The answers ranged from 50 trees to 12.4 acres — not large plantings.
- Respondents were asked if they produce a manual of sorts for growers, that provide helpful production information. Most do. This ranges from fact sheets with information about variety characteristics, rootstock options, production, and suitability for various conditions, to fully customized production manuals for each variety that include specific practices to optimize fruit set, fruit size, and quality for maximum market value.
Processing Scion Varieties
Below is a compilation of more clear-cut factors, which are the focus of fruit evaluations for processing scion varieties. No surprises here:
- Trueness to type
- Harvesting time and holding time on tree
- Some measure and publish information on tree size — including trunk and canopy
- Tree vigor: low, intermediate; growth habit
- Performance on a few different rootstocks
- Pest and disease susceptibility
- Fruit firmness. Transport of fruit for processing is harder on fruit than transport for fresh market, and fruit often sits at the plant longer before being processed. It is important to know whether the fruit can make the trip as a full load. Softer fruit may require partially filled trailers to reduce damage, resulting in additional transportation costs.
- Juice quality: brix/acid/ratio, color, presence of compounds known to cause off-flavor
- Typical samples are 50 pieces per tree – beginning, middle, and end of maturity range.
- Ability to be pasteurized or otherwise processed. Not all varieties that pass the standard juice quality assessments can be adequately processed without off-flavors and/or colors.
- Production: yield per tree, acre, or hectare.
- For processed fruit, the respondents also were asked how large trial plantings need to be in order to have confidence in the results. The answers ranged from 25 to 99 acres.
Fresh Selections Observations
Considering Florida’s unique circumstance, it is clear all of the aforementioned data is not required for a simple pre-screen. What is most important on the front end is tree health, vigor, fruit set/hold, performance on several rootstocks, and fruit marketability. Early adopters who implement small, private trials can generally glean enough information from their experience to support or decline commercial interest. However, growers who come later will need additional information to substantiate their investment and to maximize the success of the variety.
The industry will gather this information through well-designed trials established for data collection. That said, the early small-scale, private trials may assist in identifying clear losers, negating the need for larger-scale trials, preserving valuable resources. The small-scale informal trials should continue, but selections targeted at the fresh market also will require concurrent larger-scale, formal trials.
Processed Selections Observations
The scale of the plantings and the complexity of the data collection makes it more difficult for a small, private cooperator to complete the entire process. Larger corporate trials can certainly perform this function, but the sharing and comingling of data may be an issue. Trials for selections predominantly intended for processing likely will continue with private cooperator volunteers, combined with scientific trial design and data collection mechanisms.
Data generated from these trials will be of value to academics, growers, and the nursery segment. As with fresh selections, observations from early adopters will play a key role in determining the appropriate scale of larger trials and the overall suitability of the cultivar.