Gregory Michael PeckCornell University | CU · Department of Horticulture
Gregory Michael Peck
Ph.D.
About
60
Publications
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749
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Introduction
My research addresses the challenges of sustainably and profitably producing tree fruits. Current projects focus on soil ecology in high-density orchards, value-added products (i.e., hard cider), and sustainable management practices and systems.
Additional affiliations
November 2015 - present
April 2011 - October 2015
May 2010 - March 2011
Publications
Publications (60)
Although demand for organic produce continues to increase in the mid- Atlantic, few apple (Malus 3domestica Borkh.) growers in the region have adopted organic management practices due to the considerable disease, insect, and weed pressure, as well as the lack of effective crop loadmanagement tools. In this study, lime sulfur (LS) and Regalia®(R) we...
Our modern apple production systems have substantially increased in productivity and sophistication over the last several decades. Much of the rest of this book focuses on the science and technology by which those increases have occurred. However, like many other modern farming systems, increased productivity often results in undesirable environmen...
Climate change may both exacerbate the vulnerabilities and open up new opportunities for farming in the Northeastern USA. Among the opportunities are double-cropping and new crop options that may come with warmer temperatures and a longer frost-free period. However, prolonged periods of spring rains in recent years have delayed planting and offset...
Hard cider production in the United States has increased dramatically during the past decade, but there is little information on how harvest and postharvest practices affect the chemistry of the resulting cider, including concentrations of organoleptically important flavanols. For 2 years we assessed fruit, juice, and cider from a total of five app...
The environmental factors that influence cider apple fruit quality, particularly bitter and astringent polyphenols, are not well understood. Five experiments were conducted to investigate how sunlight affects fruit and juice quality. In three studies, shade cloth was placed over entire trees or individual branches at different phenological stages,...
Societal Impact Statement
Fermented “hard” cider is currently experiencing a resurgence in popularity. While there is a long history of cultivating apple trees with fruit quality characteristics intended specifically for cider production, there is a dearth of cider-specific apple production in many emerging cider producing regions, such as North Am...
ADDITIONAL INDEX WORDS. labor, machinery, Malus ×domestica, partial budget SUMMARY. Harvesting labor is the largest annual variable operating expense for apple (Malus ×domestica) orchard enterprises and is subject to escalating costs and shortages. In Europe, much of the cider apple harvesting is done with machinery, greatly reducing production cos...
Hard cider is made richer and more complex with high tannin apple cultivars which are not widely grown in the US. Many European cider cultivars are extremely biennial and are highly susceptible to fire blight which makes cultivar selection extremely important. The goal of this project was to generate information on horticultural and juice quality a...
The organic acid concentration in apple ( Malus × domestica ) juice is a major component of hard cider flavor. The goal of this study was to determine if the malic acid markers, Ma1 and Q8 , could classify the titratable acidity concentration in cider apple accessions from the United States Department of Agriculture Malus germplasm collection into...
Sustainable practices are key to the improvement of soil fertility and quality in apple (Malus ×domestica Borkh.) orchards. Rootstock genotype and fertilizer inputs can both alter soil biology, as well as aboveground traits including nutrient acquisition. In this study, a factorial design was used to assess the interaction between two apple rootsto...
The recent growth in the U.S. hard-cider industry has increased the demand for cider apples ( Malus × domestica Borkh.), but little is known about how to manage orchard soil fertility best to optimize horticultural performance and juice characteristics for these cultivars. To assess whether nitrogen fertilizer applied to the soil can improve apple...
Yeast assimilable nitrogen (YAN) can be a limiting nutritional factor for Saccharomyces cerevisiae yeast when fermenting apple ( Malus × domestica Borkh.) juice into hard cider. Endogenous YAN concentrations in apples are often below the recommended thresholds to completely use all of the fermentable sugar and minimize the production of off-flavors...
The fermentation of apple juice into hard cider is a complex biochemical process that transforms sugars into alcohols by yeast, of which Saccharomyces cerevisiae is the most widely used species. Among many factors, hydrogen sulfide (H2S) production by yeast during cider fermentation is affected by yeast strain and yeast assimilable nitrogen (YAN) c...
Hard cider, made by fermenting apple ( Malus × domestica ) juice, was at one time the most widely consumed alcoholic beverage in America. Largely abandoned after Prohibition, within the past 2 decades the rise in popularity of craft beverages has led to the reemergence of hard cider as an alternative to beer, wine, and spirits. Today, hard cider re...
Multiple analytical methods are used for quantification of total polyphenols and total flavanols in fruit juices and beverages. Four methods were evaluated in this study: Folin‐Ciocalteu (F‐C), Lowenthal permanganate (L‐P), 4‐dimethylaminocinnamaldehyde (DMAC), and the bovine serum albumin (BSA) precipitation method. Method validation parameters, i...
Amino acids and ammonium ions constitute the yeast assimilable nitrogen naturally present in apple juice, with free amino acids being the major constituent. Little information is available on the extent to which free amino acid composition in apple (Malus × domestica Borkh.) juice varies among juices used for fermentation. Twenty amino acids were q...
Apple (Malus domestica Borkh.) juice typically contains low concentrations of yeast assimilible nitrogen (YAN). During fermentation, this can cause yeast (Saccharomyces cerevisiae) cells to produce the sulfur-containing amino acids, methionine, and cysteine, a reaction that reduces sulfate to hydrogen sulfide (H2S)[1,2]. When H2S is produced in exc...
Apple (Malus × domestica Borkh.) growers require management practices that will produce high-quality fruit while minimizing the number of chemicals used for adequate disease control and horticultural practices. Certain chemicals applied for bloom thinning also have fungicidal properties and could provide protection against early season diseases in...
Yeast assimilable nitrogen (YAN) is essential for yeast growth and metabolism during apple (Malus x domestica Borkh.) cider fermentation. YAN concentration and composition can impact cider fermentation kinetics and the formation of volatile aroma compounds by yeast. The YAN concentration and composition of apples grown in Virginia, USA over the cou...
In the Mid-Atlantic, mineral nitrogen (N) fertilizers are applied in high-density apple (Malus xdomestica Borkh.) orchards to increase tree vegetative growth and achieve earlier fruiting. However, when applied in excess of plant needs, N fertilizer applications are an unnecessary expense and may lead to N leaching and groundwater pollution. Therefo...
Yeast assimilable nitrogen (YAN) concentration and composition impact hydrogen sulphide (H2S) production and fermentation kinetics during wine fermentation, but this phenomenon has not been extensively studied in cider fermentation. Our hypothesis was that H2S production during cider fermentation could be decreased through pre-fermentation modifica...
Background:
Fungicide residues on fruit may adversely affect yeast during cider fermentation, leading to sluggish or stuck fermentation or the production of hydrogen sulfide (H2S), an undesirable aroma compound. This phenomenon has been studied in grape fermentation, but not in apple fermentation. Low nitrogen availability, characteristic of apple...
A greater understanding of apple (Malus x domestica) pollen tube growth rates can improve crop load management in commercial orchards. Specifically, applications of caustic bloom thinning chemicals need to occur when enough, but not too many, flowers have been fertilized in order to achieve crop load densities that balance yields with marketable fr...
To assess the impact crop load has on hard cider chemistry, ‘York’ apple (Malus3domestica Borkh.) trees were hand thinned to three different crop loads: low [two apples per cm2 branch cross-sectional area (BCSA)], medium (four apples per BCSA), and high (six apples per BCSA). Higher crop loads produced smaller, less acidic fruit that were slightly...
Compared with the conventional practice of fruitlet thinning, flower thinning often results in greater fruit size and flower bud formation. Through the use of a temperature-based pollen tube growth model that predicts the ideal application timing of bloom thinning chemicals, we have shown that flower thinning is both a reliable and desirable techni...
The recent growth in the U.S. hard cider industry has created a tremendous amount of interest in European cider apple cultivars. While the juice from any apple cultivar can be fermented and made into hard cider, specialized cider apples are typically more tannic and/or acidic than culinary apples. Through a collaborative effort among land grant uni...
At CiderCON 2013 and 2014, we assessed the scale of current and projected production, as well as the research and Extension needs of cider apple growers and cider makers. Our findings show that cider producers are diverse in terms of geographic location, scale of operation, and experience. These stakeholders reported a great need for technical assi...
Reducing crop load improves apple (Malus xdomestica Borkh.) size and color, and increases return bloom therefore minimizing biennial bearing. Chemically thinning apple trees during bloom can be an efficient way to reduce crop load. Most bloom thinning chemicals are caustic, causing damage to floral organs, thus preventing fertilization. However, th...
Three separate experiments were conducted to test standard calcium chloride salt (CaCl2) rates and several new formulations of calcium (Ca) for amelioration of bitter pit, a Ca-related physiological disorder that affects fruit of many apple (Malus ·domestica) cultivars, including the popular cultivar Honeycrisp. Even small amounts of bitter pit dam...
Growers in four different regions submitted lists of the top cider apple cultivars grown in their area. The lists are not based on replicated trials but on field observations, and not everyone has grown every listed variety.
Polyphenols and maturity parameters were determined in 20 apple cultivars with potential for hard cider production grown in Virginia, USA. Concentrations of five classes of polyphenols were significantly different across cultivar for both peel and flesh. Total polyphenol concentration ranged from 0.9 μg/g wwb in flesh of Newtown Pippin to 453 μg/g...
Mortalities are inevitable in animal agriculture. For most animal operations in the United States, the average annual mortality is estimated to be between 4.5 and 6 percent of the livestock population. Common methods of mortality disposal include burial, rendering, incineration, and use of a landfill. The availability of options for disposing of mo...
Rootstock genotype and soil fertility management practices in apple (Malus domestica Borkh.) orchards impacts soil health and nutrient status, plant associated soil microbial communities, and tree growth and fruit yield. Growers select specific apple rootstocks for use in their orchard systems to confer beneficial traits, including size control, pr...
Since 2011, commercial cider producers throughout the U.S. have gathered at an annual trade show and educational conference in Chicago, IL called CiderCON. In both 2013 and 2014, university researchers have attended CiderCON to present findings from their research programs and to survey cider makers and cider apple growers about their research and...
By the simplest definition, hard cider is fermented apple juice. In the U.S., unfermented and usually unfiltered apple juice is referred to as cider or sweet cider. In many other countries, particularly in Europe, the fermented product is called cider and the unfermented product is called apple juice. In this article, we use the term cider to refer...
This publication describes a set of associated budget spreadsheets that utilize a systematic means to assess
the feasibility of growing specialty apple cultivars for sale to commercial hard cider producers.
Hard cider is a burgeoning part of the alcoholic beverage industry. To make a premium hard apple cider product, commercial cider-makers desire apple cultivars with high tannin, high acid, and/or high sugar content. Some commercially grown apples, such as ‘Albemarle Pippin’, ‘Winesap’, and ‘Granny Smith’ can serve these purposes. However, many cider...
Researchers have collected a considerable amount of data relating to apple (Malus × domestica) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension, re...
Researchers have collected a considerable amount of data relating to apple ( Malus × domestica ) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension,...
In apple (Malus X domestica Borkh.) production, crop thinning during bloom produces the largest fruit, the greatest return bloom in the following year, and reduces biennial bearing. The application timing for this spray has been subjective, and, in the past, was usually based upon the percent of full bloom open (e.g., an application at 20 and 80% f...
In apple production, crop thinning during bloom produces the largest fruit, the greatest return bloom in the following year, and reduces biennial bearing. There are a limited number of fruit thinning chemicals approved for use under USDA organic standards, and many organic apple growers rely on a combination of liquid lime sulfur and fish oil appli...
We recently published A Grower’s Guide to Organic Apples, one of thirteen organic guidelines released through Cornell University’s New York State Integrated Pest Management program. The guide was written in response to the many New York fruit growers who had expressed interest in producing for the organic sector, where prices are relatively high an...
We investigated soil quality in a ‘Liberty’ apple (Malus×domestica Borkh.) orchard on ‘M.9’ rootstocks, during and after transition from conventional to integrated (IFP) and organic (OFP) fruit production systems. Chemical composition, physical properties, and biological properties were measured at 0–6 and 6–12cm soil depths over four years. Weed c...
A systems-based approach was used to evaluate integrated (IFP) and organic fruit production (OFP) (during and after the transition period) in an established highdensity commercial orchard of disease-resistant ‘Liberty’ apples (Malus ·domestica Borkh.). Agroecological and economic evaluations included: yields, tree growth, leaf
nutrient levels, arth...
Many New York fruit growers have expressed interest in producing for the organic sector, where prices are relatively high and demand is increasing. However, reliable science based information for commercial organic tree fruit production in cool humid regions such as the Northeastern United States has been difficult to find. This production guide co...
Maturity and quality of fruit harvested from an orchard of disease-resistant 'Liberty' apple (Malus ×domestica Borkh.) trees was investigated during and after the transition from conventional to integrated (IFP) and organic fruit production (OFP) systems. Over 4 years, internal ethylene concentration, starch pattern index, flesh firmness, soluble s...
Terminal-Restriction Fragment Length Polymorphism (T-RFLP), a Polymerase Chain Reaction based method, was used to determine bacterial and fungal soil community composition in an orchard of disease-resistant ‘Liberty’/‘M.9’ apple (Malus × domestica Borkh.) trees during and after the transition from conventional to either integrated (IFP) or organic...
A pawpaw (Asimina triloba) variety trial was established near Ithaca, N.Y. in April 1999, consisting of 28 advanced selections and cultivars from the USDA PawPaw Germplasm Repository in Kentucky. Eight replicate trees of each genotype were obtained as dormant bench-grafts on seedling rootstocks, and planted in a randomized block design at a site ne...
Apple growers in New York lack the tools to produce high quality fruit for the organic or IFP marketplace. We are systematically evaluating OFP and IFP systems for pest control efficacy, fruit and soil quality, environmental impacts, and economic sustainability, in an orchard of disease-resistant `Liberty' on M.9 rootstock. The OFP system follows U...
Located on a 20-ha commercial apple (Malus domestica Borkh.) orchard in the Yakima Valley, Washington, a 1.7-ha study area was planted with apple trees in 1994 in a randomized complete block design with four replications of three treatments: organic (ORG), conventional (CON), and integrated (INT). Soil classification, rootstock, cultivar, plant age...
Production of some organic commodities, such as apples, is heavily concentrated in the United States (US), with Washington State being the leading US producer of organic apples. In 2003, there were 4047 ha of certified organic apple orchards in Washington State, an all-time high and a more than tenfold increase since 1989. But this growth has not o...
We conducted a comprehensive, long-term, systems-level experiment comparing integrated (IFP) and organic fruit production (OFP) systems in an established commercial orchard of disease resistant 'Liberty' apple trees on M.9 rootstock. In Year 1 (2004), both systems were equally productive and net returns were similar but the variable costs for OFP w...
Projects
Projects (9)
Determining the effects of carbon-based fertility amendments and rootstocks on apple tree nutrition and soil quality
This project seeks to enhance economically and environmentally sustainable practices in temperate fruit production by focusing on rootstocks. The NC-140 project meets the guidelines presented by the North Central Regional Association (NCRA) in Guidelines for Multistate Research Activities (May 2001). Specifically, this project addresses high priorities defined by NCRA, within the crosscutting research areas of agricultural production, processing, and distribution, genetic resource development and manipulation, integrated pest management and economic development and policy. The project involves researchers from multiple states and is multidisciplinary. Researchers involved in this project have leveraged Federal and state dollars to add significant resources to address this research area. Lastly, outreach is integral to the project and includes electronic information transfer through web sites, written material for growers and other stakeholder groups, and numerous educational programs in individual states and at national and international grower and scientific meetings. http://www.nc140.org/
