Research Interests


  • Tree fruit physiology
  • Abiotic stress
  • Plant nutrition
  • Impacts of preharvest environment on postharvest physiology


Research Projects


Accelerating the development, evaluation, and adoption of new apple rootstock technologies to improve apple grower profitability and sustainability (2016-2021)
Project Director: Lailiang Cheng; Co-PDs: Lee Kalcsits, Gennaro Fazio, Mark Mazzola, Terence Robinson, Bradley Rickard, Stefano Musacchi, Esmaeil Fallahi, Teryl Roper, Greg Lang, Philip Schwallier; Co-Investigators: Grant Cardon, Brent Black. USDA Specialty Crop Research Initiative.

The US apple industry needs to improve the economic and environmental sustainability of current production systems by utilizing rootstocks that improve disease resistance, tolerate abiotic stresses and positively influence fruit quality and yield. Through this project, we will accelerate the development, evaluation and adoption of improved apple rootstocks by targeting research areas not currently being addressed. We will focus on both evaluating new candidate rootstocks and identifying genetic markers for difficult to phenotype complex root traits like replant disease tolerance, nutrient uptake and partitioning (especially calcium), low/high soil pH and salinity to improve tolerance of rootstocks to these biotic and abiotic stresses, and improve fruit quality of high value cultivars.

Defining the mechanisms of Ca related disorders in tree fruit (2016-2017)
Principal Investigator. Co-PI: David McNear. Lawrence Berkeley Advanced Light Source, Berkeley, CA. 

Apple production in Washington State is more than a $2 billion industry, producing nearly 70% of the nation’s apples. One of the major disorders significantly increasing post harvest losses (in some cases >30%) and reducing the marketability of apples is bitter pit. The overall goal of this project is to determine if bitter pit in apples is due to degradation in vascular tissues within the fruit inhibiting the delivery of Ca (and other elements) to these regions. We will to use synchrotron-based techniques to determine the vascular structure (phase-contrast micro tomography), elemental distribution (µ-SXRF) and speciation (µ-XANES, µ-EXAFS) to ascertain the mechanisms contributing to the development of bitter pit in tree fruit.

Calibration development for nutrient analysis using a handheld XRF (2016-2017)
Principal Investigator. Washington Tree Fruit Research Commission

Previous work has demonstrated that a handheld x-ray fluorometer (XRF) can be used for non-destructive, semi-quantitative measurements of calcium and potassium in apple and pear fruit. However, current methods to estimate differences in calcium and potassium among different fruit or lots of fruit is not automated and the user receives a semi-quantitative estimate that is only valid for relative comparisons with other fruit and cannot be related to historical lab measurements. To increase the usefulness of this instrument for industry, we will identify how correlations between x-ray and lab analysis differ among apple and pear varieties with known differences in skin thickness, develop cultivar-specific and skin-thickness specific calibrations for non-destructive analysis of calcium and potassium in apple and pear and incorporate quantitative calibrations into the XRF software for industry-friendly instrument use.

Precision application of organic amendments for improved soil quality in replant apple orchards (2016)
Principal Investigator: David Brown; Co-PIs: Lee Kalcsits, Caley Gasch and Mark Mazzola. CSANR BioAg Grant Program

During apple orchard renewal, Apple Replant Disease (ARD) and soil degradation can lead to inconsistent infill vigor and uneven fruit production. Brassica seed meal is an effective organic amendment for suppressing ARD and improving soil fertility in new plantings, but it is expensive and not necessary for orchard areas that do not express ARD. We will investigate spatial predictors of ARD and whether site-specific application of organic soil amendments can be used to suppress ARD, improve general soil health, and promote uniform tree growth.

Sensor-based precision orchard management (2016)
Co-PI. WSU CAHNRS Emerging Research Initiatives

Cosmic Crisp: Training system and orchard management to optimize vigor control and quality (2015-2018)
Principal Investigator: Stefano Musacchi; Co-PIs: Lee Kalcsits, Karina Gallardo, Desmond Layne. Washington State Department of Agriculture Specialty Crop Block Grant

The WSU apple breeding program recently released a very promising variety, WA 38 (trade name Cosmic Crisp™), characterized by an unusually firm, crisp and juicy texture and excellent storability. Current grower demand for this variety greatly exceeds supply and it is clear the variety will be widely planted throughout the state over the next five years. Thus, Washington apple producers will require critical information on horticultural management issues. Horticultural performance will be evaluated using innovative 2 or 3 axis training systems. In addition, we will analyze the horticultural and economic aspects of orchard establishment of Cosmic Crisp™ using a top grafting approach, which can bring an orchard into commercial production faster than the usual practice of planting young trees. Our lab will perform carbon assimilation and distribution tests, root imaging via root tubes installed in the soil, fruit growth and nutrient analysis, and fruit bitter pit evaluation.

Physiological responses of apple under photoselective hail netting (2015-2018)
Principal Investigator. Co-PIs: Stefano Musacchi, Desmond Layne. Washington State Department of Agriculture Specialty Crop Block Grant

In this project we will evaluate photoselective anti-hail nets as an alternative to irrigated overhead cooling to reduce sunburn in tree fruit orchards. The goal is to measure the impact of netting on the orchard agroecosystem including physiology, soil characteristics, microenvironment and light conditions to determine how those changes impact horticultural requirements of tree fruit grown under anti-hail nets.