Location: National Clonal Germplasm Repository
Project Number: 2072-21000-059-005-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Mar 2, 2023
End Date: Dec 1, 2026
Objective:
Objective 1: Understand the chemical underpinnings of “premium” flavor in non-commercial strawberries. Previous studies investigating the chemical constituents contributing to strawberry flavor have primarily focused on the aroma attributes (volatiles) and two main taste attributes (sweetness and sourness). This approach is ‘incomplete’ with limited resultant outcomes because it ignores the contributions of flavor modulators4-5, textural
(somatosensory) sensations6–8, and flavor-flavor interactions9 that influence flavor perception and product liking. This project will use sensory preference mapping techniques to define what constitutes a premium strawberry flavor and the specific sensory attributes that drive liking. The chemical stimuli of premium flavor will be comprehensively defined, for the first time, using state-of-the-art analytical tools for flavor discovery that define aroma, taste, somatosensory, and modulators of strawberry flavor. There is relatively limited knowledge on flavor modulators and textural attributes from strawberry flavor, particularly in comparison to its aroma, which impedes successful adaption to PIP environments. For example, Dubrow and Peterson10,11 recently reported four non-volatile strawberry compounds that functioned as flavor enhancers in jam and contributed to product liking.
Objective 2: Develop genetic markers for premium flavor to enable novel germplasm generation Heritable genetic variation has been uncovered for a few compounds associated with consumer preference in strawberry; however, hundreds of secondary metabolites potentially influence flavor. Identifying specific clones with premium flavors and associated compounds will provide the basis for genetic characterization and a foundation for breeding. For compounds under significant genetic control, we will develop predictive genetic markers associated with candidate genes involved in their biosynthesis. We will leverage high-quality reference genomes and high-density marker genotyping platforms to construct a chromosomescale map12 for visualizing control of premium flavor on the octoploid strawberry genome. In addition to identifying genetic sources of premium flavor in the global germplasm base, identifying genetic markers and genes associated with underlying compounds driving premium flavor will accelerate selective breeding for high-value indoor strawberry cultivars. Outcomes will be the identification of germplasm, creation of new populations, and linked genetic markers which will inform a platform for the identification and selection of novel genetics for breeding to address long-term improvement under PIP.
Approach:
Premium strawberry flavor will be identified using preference mapping techniques that include overall and attribute-specific liking (e.g. pineapple notes). Preferred strawberries and the defining sensory characteristics will guide the chemical analysis of components contributing to premium flavor. A combination of targeted and untargeted GC and LC methods for the ‘comprehensive’ discovery of volatile and non-volatiles compounds will be used to identify aroma, taste and somatosensory compounds as we have previously demonstrated and to identify flavor compounds and modulators that contribute to consumer liking and disliking as we have previously described. A panel of several hundred octoploid varieties reflecting the breadth of genetic diversity will be used for targeted measurements of premium flavor components under optimal PIP conditions. In parallel we will fingerprint the collection using a 50K SNP array developed for strawberry. Genome-wide association studies, reference genomes and functional
annotations will identify candidate genes, markers, and germplasm for improving premium flavor. The genetic and trait data generated in this project will be deposited in the Genome Database for Rosaceae to provide a resource for future breeding.
Using a PIP system at OSU, we will produce strawberry fruits using a hydroponic method as described in OSU’s Indoor Strawberry Website. Starting with light intensity (daily light integral) and day/night air temperature regimes known as factors affecting strawberry fruit primary quality in greenhouse, we will determine their effects on the selected flavor compositions and their relevant gene expressions. We will also examine selected root-zone factors such as nutrient solution formula and overall salinity in the nutrient solution.
