Skip to main content Skip to navigation

2023 WA Tree Fruit Research Commission Grant Awards for Apple Horticulture and Postharvest

Washington Tree Fruit Research Commission logo

Date: March 2023

Authors: Paige Beuhler and Ines Hanrahan

The Washington Tree Fruit Research Commission approved $562,722 to help fund seven (7) new Apple Horticulture and Postharvest projects for 2023.

2023 New Apple Horticulture and Postharvest Project Details

Project Title: Measuring Storage Reserves to Assess Severity of Biennial Bearing

Organization (s): Washington State University

PI (s): Kalcsits, L.; Blanco, V.; Campbell, T.

Total Funding Amount for All Years: $58,927

Length: 1 Year

Biennial bearing remains a major challenge for Washington State apple growers. Biennial bearing affects long-term orchard profitability, control of disorders, and the ability to produce a consistent product for the consumer. While the role of hormones on the biennial bearing cycle have been closely studied, measurements that predict risk of off-years and smooth out annual production still need to be developed. Historically, the role of non-structural carbohydrate (NSC) and nitrogen (N) reserves on biennial bearing have been established for many fruit species. However, these relationships need to be more closely assessed in modern apple orchards. The use of NSC and N concentrations as risk metrics for newer cultivars and in modern, high-density systems has potential because of lower storage potential from highly productive orchard systems. Kalcsits and his team plan to establish baseline levels of carbohydrate concentrations in storage organs of apple trees that are in different biennial bearing cycles, and then establish cost-effective and industry-adoptable methods for measuring non-structural carbohydrates in apple trees.

Project Title: Life Cycle Assessment for Pacific Northwest Apple Production

Organization (s): Resilience Services, Blonk Sustainability Tools, Washington State University

PI (s): Thoma, G.; Blonk, H.; Yorgey, G.

Total Funding Amount for All Years: $514,819

Length: 3 Years

Produce buyers and the federal government are directing the adoption of “climate-smart” agricultural practices. In September 2022, the United States Department of Agriculture announced $2.8 billion in funding for the Partnerships for Climate-Smart Commodities Program to finance partnerships supporting climate-smart commodities’ production and marketing via pilot projects lasting one to five years. Minimal emphasis has yet been focused on fruits, vegetables, or orchard crops. Nonetheless, buyers are engaging suppliers in sustainability initiatives, including climate action, requiring producers to reduce climate impacts in several categories, including energy use, waste reduction, packaging, nature preservation, and transportation. There is currently no research evaluating the impacts of producing Pacific Northwest tree fruit on climate change.  Data specific to Pacific Northwest tree fruit production estimating greenhouse gas (GHG) emissions (e.g., carbon dioxide from combustion and N2O from denitrification in soils) and sequestration (i.e., storage of carbon in soils and biomass) is needed to fill knowledge gaps in our understanding of the potential environmental costs and benefits of producing Northwest tree fruit. The primary project goal is to provide a baseline assessment of the environmental sustainability of PNW apple production and to develop a prototype modeling platform that will support the evaluation of management decisions over the orchard lifecycle and provide the standard against which future improvements can be documented. These objectives will be achieved through stakeholder-engaged efforts to define the sector’s most relevant data and sustainability metrics.

Project Title: Phase 3 Evaluations of WSU Apple Breeding Selections

Organization (s): Washington Tree Fruit Research Commission

PI (s): Mendoza, M.

Total Funding Amount for All Years: $169,396

Length: 3 Years

New and improved apple varieties are essential to enhance a successful Washington apple industry. The goal of the WSU apple breeding program (WABP) is to produce a portfolio of new, improved, unique varieties specially selected for the environment of central Washington and available to Washington’s growers. The development of improved apple varieties leads to sustainable production and enhanced postharvest efficiency to promote sustainability and long-term economic viability by increasing apple packouts. The WABP has exciting new material in the selection pipeline. Phase 3 (P3), the pre-commercialization phase of the WABP, includes larger plot plantings of the elite selections to determine potential commercial suitability. Currently, five selections are planted in three grower-collaborator sites. The advantage of this arrangement is the ability to observe the growth habits and characteristics of advanced selections in a commercial production setting. Having the WTFRC manage P3 provides an independent and industry-oriented evaluation that, with the input of industry representatives in the apple breeding program advisory committee (BPAC), ensures that the data collected and information provided align with stakeholders’ interests. The project results, including single pick potential, harvest window, storability, and resistance to biotic and abiotic stress, are presented to the BPAC annually. Field visit opportunities are included throughout each season. Mendoza and her team will evaluate and determine the commercial potential of advanced selections of the WABP by observing bud and bloom, fruitlet development and pre-harvest, harvest, and post-harvest of the P3 varieties.

Project Title: Genomic Approaches to Understand the Etiology of Postharvest Decays

Organization (s): Washington State University, USDA-ARS, Hudson Alpha Institute for Biotechnology

PI (s): Amiri, A.: Honaas, L.; Ficklin, S.; Harkess, A.

Total Funding Amount for All Years: $180,310

Length: 2 Years

Tens of thousands of genes are expressed in fruit at different phenological stages and in fungal pathogens under different physiological conditions, and the activity of many of these genes are highly dynamic in pre and postharvest. By understanding gene activity in both the fruit and the pathogen, new knowledge could be acquired about poorly understood mechanisms that render fruit susceptible to decay. Research has shown that important postharvest pathogens such as Penicillium expansum (blue mold) and Botrytis cinerea (gray mold), which combined can cause up to 70% of total decay in Washington State, have different gene activity profiles or can induce different gene activities in the host during infection. While the short-term goal is to use new genomic tools to enhance knowledge about genes expressed in major cultivars grown in WA during extended periods of time pre and postharvest, the long-term goal would be to model gene expression and detect gene activity signatures or markers which may predict the risk of pathogen development in a given fruit lot to facilitate pre and postharvest decisions making in term of management and storage.

Project Title: Improving Apple Fruit Quality and Postharvest Performance

Organization (s): Washington Tree Fruit Research Commission

PI (s): Mendoza, M.

Total Funding Amount for All Years: $76,413

Length: 2 Years

The Washington Tree Fruit Research Commission internal program aims to provide support to scientists and industry members and tackle high-priority industry needs not otherwise covered. This project was funded to evaluate new technologies to assess fruit quality parameters in a more efficient way, as the standard assessment methods of assessing fruit firmness and soluble solids are destructive and time-consuming, while also generating fruit waste, decreasing marketable fruit, and only allowing for small sampling assessments. Mendoza’s project will test a low-energy microwave sensor, which can penetrate deeper into the fruit while having the potential to define several quality attributes in a single measurement. If accurate, this non-destructive method could decrease workload, provide more timely and continuous results, and reduce fruit waste. This project will also investigate the effect of 1-MCP on WA 38 starch degradation and fruit flavor during RA and CA storage.

Project Title: Efficacies of Biocontrol Agents Against Postharvest Decay in Apples

Organization (s): Washington State University, Washington Tree Fruit Research Commission

PI (s): Zhu, M.; Mendoza, M.

Total Funding Amount for All Years: $263,840

Length: 3 Years

Blue and gray mold can account for upwards of 50 percent of the annual fruit loss during a production year, and P. expansum can also produce a toxic patulin, concerning packers, processers, and consumers alike. The impacts of decay organisms are even more significant for organic fruits, where there are limited numbers of postharvest organic fungicides and cultural practices available, while the volume of organically grown apples continues to grow. These along with growing public concern over synthetic fungicides, especially in postharvest, highlight the need for new decay control strategies. Biocontrol agents are a promising alternative to chemical fungicides for postharvest decay control because they could be used in organic production, do not have any known chemical residues, are environmentally friendly, and have less chance of developing pathogen resistance. The overall goal of this project is to evaluate the potential of commercial biocontrol agents individually and in combination with decay control. The team will first in vitro  screen the inhibitory effects of commercial biocontrol agents alone or in combination against Penicillium expansum, Botrytis cinerea, and  Mucor piriformis. They will then evaluate the efficacy of the selected biocontrol agents or combinations on rots of pre-wounded apples artificially inoculated with P. expansum, B. cinerea, or  M. piriformis during storage. Next, they will assess the efficacy of the selected biocontrol treatments on apples artificially infected by the major decay pathogens in commercial cold storage without wounding. Finally, they will evaluate the efficacy of the selected biocontrol treatments on naturally infected apples without wounding or pathogen inoculation. This project addresses the research priority of assessing the effectiveness of new biocontrol agents or other novel agents for decay control. The proposed studies will fill knowledge gaps on organic approaches to reduce food loss and provide the industry with scientifically validated data and guidelines for decay/patulin control and management. The identified biocontrol agent will also work for conventional fruits. It may be also applied for pre-harvest application.

Project Title: Ozone Nanobubble to Control Listeria and Decay in Organic Apples

Organization (s): Washington State University, Washington Tree Fruit Research Commission

PI (s): Zhu, M.; Mendoza, M.

Total Funding Amount for All Years: $251,864

Length: 3 Years

Organic apple production in Washington continues to increase rapidly. Organic apples are more challenging to grow than conventional ones. Listeria monocytogenes is a continuous concern for both organic and conventional apples due to its widespread distribution and outbreaks and recalls linked to apples. Listeria can grow on apple slices or wounded sites of caramel-coated apple surfaces. It is stable on fresh whole apples during cold storage and Listeria can survive in packing facilities/environments over time. Apples can be contaminated by foodborne pathogens during packing and processing. The overall goal of this study is to employ ozone nanobubble technology to control L. monocytogenes and decay organisms during apple packing. The effectiveness will be further verified in a pilot-scale processing facility. In direct response to industry input and to address these commercially critical questions, Zhu’s team will pursue three specific objectives, including evaluating and optimizing the efficacy of ozone nanobubbles against L. monocytogenes on fresh apples and water which will be further compared with commonly used sanitizer PAA, evaluating the efficacy of ozone nanobubble interventions along with PAA against decay organisms on water and apples, and finally verification of the effectiveness of the ozone nanobubble interventions against L. monocytogenes and decay organisms in a pilot-scale apple packing line.


Paige Beuhler (Administrative Officer):, 509 665 8271 ext. 2

Ines Hanrahan (Executive Director):; 509 669 0267

Washington State University