For Citrus Variety Development, The Drawing Board Is Full
Due to the rapidly changing landscape of plant patents and licensure, much has been written about commercialization models and the processes through which citrus nurseries and growers can access, trial, and/or produce new citrus varieties. However, the support of variety development projects lies at the core of New Varieties Development & Management Corp.’s (NVDMC) mission.
Though some sponsored projects are annually adjusted long-term programs, others are new and innovative efforts to improve the development and commercialization process. Florida is making substantial investments in the development side of the equation, and this month’s article will highlight the 2016-2017 projects approved by the NVDMC Board of Directors and supported through the Florida Department of Citrus and the Florida Citrus Commission.
Citrus Scion Variety Development At UF-CREC
The UF/IFAS Citrus Research and Education Center (CREC) citrus breeding team has been working for more than 30 years on the development of new sweet oranges for processing, fresh market consumer-friendly mandarin/tangerines, improved grapefruit and unique acid fruits, and other novel innovations. Dr. Fred Gmitter has frequently reminded us that “citrus variety development is a continual process, one that builds successively on the work already undertaken,” it is truly an incremental process, but one that grows more focused and efficient year to year.
Though it is incremental and gradual, constant adjustments and redirection — necessitated by changing growing and market conditions fueled by industry input — enhance the value and utility of new releases. Below is a top-line overview of this project:
- The CREC team has developed by far the largest library of diploid and tetraploid citrus breeding parents in the world. They continue to use somatic hybridization and other methods to expand the collection and improve the breeding value of the parents; in particular, those which demonstrate a propensity to pass along disease resistance are increasingly utilized. This approach will lead to development of new, high-quality processed and fresh varieties with elevated levels of resistance to disease.
- There are thousands of unique hybrids planted in the field, many of which are fruiting for the first time. The most promising individuals are identified through bi-weekly observations for advanced trials and potential release.
- New hybrid families are made annually using the best parent lines developed over the past three decades.
- Recent and future crosses are focused on maximizing the necessary disease-resistance genes.
- There is a focus on improved fruit quality and resistance in very early and late-maturing easy peel mandarins as well as grapefruit and oranges for juice and fresh markets.
- Tissue culture methods have been used to incorporate genetic seedlessness from Satsuma mandarin into Florida varieties through cybridization and to recover triploid seedless hybrids through embryo rescue. Seedless fresh mandarin types also have been developed by moving the genes for female sterility from Seedless Kishu into new hybrid families.
- Improved grapefruit hybrids that may incorporate tolerance to citrus canker and HLB are being produced. Some of this work is being done through cybridization where the nuclear genomes of grapefruit are combined with the cytoplasm of other disease-resistant types of citrus or relatives.
- Somaclonal variation (difference found in citrus that has undergone some form of tissue culture regeneration) is being exploited to develop sweet oranges with superior traits. This process already resulted in the release of earlier maturing Valencias and an improved Hamlin and the OLLs (Orie Lee Late) with exceptional fresh fruit and processing quality.
- Botanical descriptions of promising selections are prepared to support commercialization. Research is continuously conducted to better characterize varieties already released. The FAST TRACK release program moves the most promising material into the industry as quickly as possible.