UF/IFAS Blueberry Breeding Program Update
Florida producers continue to face major challenges as global production during the historical “Florida window” puts downward pressure on prices. As a land grant university, the University of Florida’s mission is to help Florida growers, nurseries, marketers, retailers, and ultimately Florida consumers.
This is accomplished through different departments within the Institute of Food and Agricultural Sciences (IFAS), and within many different research and extension programs. Among them, the UF/IFAS blueberry breeding program has always supported Florida producers by developing new cultivars that can provide an advantage to producers. Yield, timing of production, disease/pest resistance, fruit size, a drier and smaller scar, and better flavor are some of the traits we continue to improve through the breeding program. The following are summaries of projects that are currently underway, to keep our producers up to date with the different levels of research occurring in the breeding program, and in collaboration with several UF/IFAS experts:
Updates to the breeding program website. An extension tab was added to the blueberry breeding website (blueberrybreeding.com) that includes information posted by Doug Phillips (blueberry extension coordinator), as well as a listing of all available UF EDIS blueberry publications, with a summary description and link to each. In addition, we expect the 2019 cultivar performance data to be posted to the website very soon, which will include yield, production timing, number of weeks to produce 10%, 50%, and 90% of the crop, and fruit quality characteristics.
A disease and insect scouting guide is being developed: In coordination with other UF blueberry researchers, we are developing a Florida-specific scouting guide which will be released as a phone app. This will provide Florida growers with a tool to support field diagnosis of disease, insect, and other plant damage. The app will include descriptions of symptoms, images, and links to UF EDIS blueberry publications. The idea of this mobile application is to support blueberry producers; however, the recommendation is that producers continue to contact the IFAS plant pathologist and entomologist. and send samples to the UF/IFAS plant clinic to diagnose major issues.
Central Florida cultivar trials: Our southern highbush cultivar trial in central Florida is now one year old, and we are continuing to monitor performance. When the plants are three years old, we will begin to apply hydrogen cyanamide to one of the two variety trials and evaluate performance under both a deciduous and an evergreen system. At that point we plan to begin to use this trial for field day demonstrations.
Early selection test sites for evergreen production: An additional trial site for early breeding materials was established in south-central Florida during 2019, for a total of two such sites. This will allow for earlier selections of materials that may be successful in the evergreen production system used in central and south-central Florida. Following the 2019 season, the first set of elite selections under an evergreen system were made from one of these sites, and will be grown out as advanced selections in multiple trial sites.
The above items have only been possible because of the hiring of Doug Phillips, central Florida blueberry specialist. Doug is providing great support to growers and researchers by facilitating day-to-day communication. In addition, Doug is currently carrying out end of season surveys across the state, with the goal of learning from issues and challenges to avoid them in future seasons.
New production system to maximize profitability: Substrate production (i.e., soilless or container production) is trending globally. While it involves a higher investment, this intensive production system has been shown to be promising in several respects, and thus could prove to be more profitable. Together with Dr. Gerardo Nuñez, and in collaboration with Straughn Farms, we have established a large substrate experiment where we are testing different substrate mixes, pot sizes, and plant architectures. The results of this experiment during the first year were above expectations. In order to make recommendations, we need to gather more information and confirm the good performance of the first year. Yang Fang, a PhD student in the blueberry breeding program, is the project lead.
Machine harvesting research: With decreasing labor availability, more producers are hiring imported labor at a significantly higher cost. Harvesting with machines can decrease this cost to a fraction of the imported labor cost. Thus, developing cultivars with good machine harvesting performance is an important goal for the breeding program. We have intensified our efforts to identify high yielding cultivars with sufficient fruit firmness and concentrated fruit production for machine harvesting. Fruit firmness is probably the most important trait for new cultivars for use in machine harvesting. Work continues to identify the genetic basis of fruit firmness, so we can accelerate the process of selecting for this trait. In addition, we began measuring pedicel length and detachment strength during the 2019 season, which are also important for machine harvesting.
Better flavor and more blueberry consumption will benefit all stakeholders: Research studies have shown that flavor is one of the most important traits for consumers. While most people will say that the market is not paying for quality, there is growing evidence that fruit from certain cultivars has been excluded from specific stores, or cannot enter at a premium price level, due to flavor characteristics. By improving blueberry flavor, we can increase blueberry consumption and thus everyone in the production chain benefits. There has been a significant effort in this area for a long time in the breeding program. With the information collected over the years, we now have a much better understanding of the components that control blueberry flavor. By 2020 we will begin incorporating molecular-marker assisted selection for the most important flavor components.
Accelerating the development of cultivars: The use of molecular markers to accelerate the process of selection in plant breeding has been proven in many species. However, the genetics of blueberry is more complex than that of many other plants. After proving these molecular methods can be used in blueberry, and optimizing the methods specifically for blueberry, we will begin implementing them in 2019 to accelerate the selection of better cultivars.
Wild species have been the basis of the Florida blueberry industry: In the past, the use of Vaccinium species naturally occurring in the southeastern US made creation of the southern highbush blueberry possible. In collaboration with Dr. Paul Lyrene, we are continuing to explore the variability of these species, and the incorporation of traits that are lacking in cultivated species.
Disease and pest screening of cultivars and new selections: In collaboration with Dr. Phil Harmon and Dr. Oscar Liburd, we are working to develop screening protocols for the most important blueberry diseases and pests. Norma Flor, a postdoctoral associate, is currently working in screening early selections and developing high throughput protocols for diseases, while PhD student Marice Lopez will be working to develop a reliable protocol for screening for gall midge susceptibility. We have observed significant problems with mites in the state, and limited options currently exist to control them. We have noted important differences between cultivars in their resistance to mites, and will thus be exploring how we can better characterize mite susceptibility in the breeding program.
Focused research on blueberry pollination: John Ternest recently joined Dr. Rachel Mallinger’s lab as a PhD student focused on blueberry pollination issues. John and Rachel will be conducting trials and research in multiple areas related to blueberry pollination over the next few years, including fruit set, floral characteristics that attract pollinators, the impact of managed and wild pollinators, and other issues.
Hydrogen cyanamide dosage: In collaboration with Dr. Jeff Williamson, we are conducting an experiment to determine the appropriate level of hydrogen cyanamide to be applied to the recently released cultivar ‘Optimus’. This is because in 2018 we observed decreased performance in this cultivar, which appears to be related to hydrogen cyanamide issues. We observed small differences across treatments in 2019, and will re-run the experiment for a second year in 2020 before releasing recommendations. We also performed this experiment on an elite selection with high potential to be released as a cultivar. Every year we expect to include new elite selections in this type of experiment, so that by the time of cultivar release this information will be available to growers.
A new potential cultivar for 2019. We are in the process of releasing a new cultivar. This selection has had consistent performance for the last few years. It is late blooming, but has a short bloom-to-ripening period with early fruit production, large fruit, and concentrated ripening. In addition, we evaluated its performance for machine harvesting with excellent results. More information will be available as soon as the release process is completed.
