Sights Set on New Citrus Demonstration Block in Florida
Losing the trial and citrus scion demonstration block at the Krezdorn Farm at Conserv II in Orange County was deeply felt, a fact highlighted by an article I wrote last year. That loss has spurred New Varieties Development and Management Corp. (NVDMC) to explore new site options for a new trial and citrus demonstration block. As the NVDMC team evaluated private cooperators, research and education centers, foundation farms, private research sites, etc., they also focused on designing the new site to make the best use of very limited resources and to construct and maintain something that will be of value to the industry.
NVDMC reached out to growers who maintain small, private scion trial sites, asking them about their design and seeking suggestions for the new NVDMC trial and demonstration site.
Here are a few key insights they gained:
- Most sites are located in or on the edge of a functioning commercial grove, rather than set apart. This simplifies caretaking and minimizes expense.
- Only a few growers have the same rootstocks for each scion. Most have a range of rootstocks, as the choices available to growers change rapidly, and growers want to get a look at a range of combinations in the hopes of hitting on a winning formula. In some cases, what started out as very structured soon grew into an interesting block with a lot of variables.
- Most growers use the same horticultural caretaking practices as in their commercial groves and purposefully avoided special treatment for the scion trial block. This gives them a better idea of performance under normal conditions.
Very little data was collected. Some growers ran brix. Very few calculated acid or ratio. Less than half recorded notes of observations. The typical use of these blocks is to make observations of overall tree health, eyeball what seems to be producing well, and gauge acceptable quality through cut and taste.
- Many growers allow friends and neighbors to visit their blocks, but most had little interest in public or larger-scale field days or requests for visits from people they don’t know.
- The majority of blocks include only the fruit types currently grown and marketed by the grower.
- Most agreed that varieties targeted at processing require more data, and that small, private trial blocks can generate interest and help inform decisions. But a larger bank of data on tree health, quality, and production on various rootstocks would be needed before making a significant investment. Growers targeting the fresh market seem more willing to make planting decisions based on what is seen and observed in the private trial block.
Recommended Next Steps
This process has certainly informed NVDMC as it plans the next steps toward reestablishing its scion trial and demonstration block. The board is considering the following recommendations for the replacement block:
- The block should contain a wide range of scions, including fresh and processed varieties.
- Chose a location with caretaking services available under contract. This will be small acreage and it would be inefficient to manage as an independent grove. This may be an issue for some fresh selections requiring isolation (for lower seed counts), but this remains the most sensible approach. Ensure that Orlando or some other common pollen source is included or nearby.
- Choose two or three rootstocks that perform well in the growing conditions on the farm site and stick with them for all scions to be planted. This will provide a more fair comparison. Use readily available commercial stocks. It may be worth trying more in a small scale for comparison.
- There is a range of opinions on this. Suggestions range from three to 50 trees of each scion on each rootstock for trial and demonstration. Due to space and budget constraints, NVDMC will likely include five or six of each scion/rootstock combination.
- Include a control of each variety type for comparison: a standard for grapefruit, mandarins, orange, etc.
Choose an easily accessible site that has good security but where arrangements can be made for escorted private and group visits. Produce and maintain an accurate map of the planting. Label trees if possible, including scion, rootstock, and planting date.
- Reserve a fixed number of trees of each scion and rootstock combination for data collection. Granted, this may not be statistically valid data with so few trees, but it would be useful information gathered over time. Tag or mark the remaining trees as demonstration trees and leave the fruit on for visitors to sample.
- It would be helpful to have sites in the River, Ridge, Flatwoods, and North. However, this is too costly. Chose one site that best fits the objectives and then later, if possible, seek plantings in the other areas with funding from an outside source.
Data gathered at the main site should be basic:
- Tree vigor and overall health.
- Fruit quality.
- Size range of fruit and/or average weight of fruit.
- Brix acid ratio at two or three points in the maturity range of the variety.
- There was no consensus on color score — still under consideration.
- Do not try to gather information for more subjective characteristics such as peel-ability. Leave that for observation later.
Whereas young tree crops might normally be stripped and discarded to allow for canopy establishment, young tree fruit in the trial block should be saved and tested. The main objective is to generate as much information as quickly as possible.