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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic, Metabolic, and Physiological Factors Regulating Deciduous Tree Fruit Quality

Location: Physiology and Pathology of Tree Fruits Research

Project Number: 2094-43000-006-00-D
Project Type: In-House Appropriated

Start Date: Jun 24, 2010
End Date: May 3, 2015

The long-term objective of this project is to develop tools to assist in marker-assisted selection and quality management of deciduous tree fruits. Over the next 5 years this program will focus on the genetic, metabolic and physiological mechanisms underlying fruit texture, aroma, and physiological disorders (Appendix 1) based on the following objectives: Objective 1: Identify genetic factors regulating apple cultivar-specific fruit texture and aroma production. Objective 2: Characterize the physiological basis for external necrotic disorders and identify genetic and/or metabolic markers associated with disorder development. •Sub-objective 2.a. Discover biomarkers that predict, diagnose, and/or distinguish apple superficial scald and soft-scald. •Sub-objective 2.b. Validate prospective biomarkers that predict, diagnose, and/or distinguish apple superficial scald and soft scald. Objective 3: Determine how environmentally-induced changes in apple fruit physiology affect onset of physiological disorders.

Research to elucidate genetic regulation of apple fruit texture and aroma will utilize established molecular analytical techniques. All analyses will use resources in place in the research unit. The apple germplasm to be utilized is available via an ongoing collaboration with the Washington State University Apple Breeding Program. This includes reference cultivars as well as a large cross population specifically established for studies related to fruit texture. Metabolomic studies will utilize fruit obtained from commercial and research orchards with chemical analyses conducted using location resources. Chemical analyses (GC- and LC-MS) will be performed using established methods where available with new methods developed as needed. Fruit will be stored using the location’s cold storage and controlled atmosphere facility which consists of 140-2 bushel chambers in which N2, CO2, and air are manipulated to achieve desired proportions in each chamber. Individual chamber temperature control is available for 20 chambers. Field experiments will be primarily conducted in commercial orchards to allow microclimate effects to be evaluated under a range of geographic and horticultural management conditions. Fruit microenvironment prior to harvest will be manipulated using polyethylene bags. Evaluation of fruit epidermis by SEM will utilize equipment in place in the research unit.

Last Modified: 10/19/2017
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