Rob Crasswellerr

Rob Crasswellerr
Pennsylvania State University | Penn State · Department of Plant Science

BSc. Miami University, MS. Ohio State University, Ph.D. Ohio State University

About

102
Publications
12,751
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
896
Citations
Citations since 2016
14 Research Items
380 Citations
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
Additional affiliations
January 1984 - present
Pennsylvania State University
Position
  • Professor of Horticulture

Publications

Publications (102)
Article
‘Honeycrisp’ is a popular apple cultivar, but it is prone to several disorders, especially bitter pit. Previously reported models for predicting bitter pit are biased, indicating that the models are missing one or more important predictor variables. To identify additional variables that may improve bitter pit prediction, a study was undertaken to i...
Article
Full-text available
In 2014, a multi-year orchard experiment of apple Malus domestica (Borkh) was established at 14 locations in Canada, Mexico, and the United States using 'Honeycrisp' as the scion. Seventeen dwarf and semi-dwarf rootstock genotypes were tested, specifically: Budagovsky.10 (B. Malling rootstocks M.7, MM.106, and the Vineland rootstocks V.1, V.5, V.6,...
Article
Full-text available
‘Honeycrisp’ ( Malus × domestica) apples were harvested from a total of 17 mid-Atlantic orchards during 2018 and 2019 to verify a previously published bitter pit prediction model. As in the previous study, bitter pit incidence was associated with low calcium (Ca) levels and high ratios of nitrogen (N), potassium (K), and/or magnesium (Mg) to Ca in...
Article
In 2010, an orchard trial of apple rootstocks was established at seven locations in the United States and Mex-ico using 'Zhen ® Fuji Aztec c.o.v. ' as the scion cultivar. Rootstocks included two named clones from the Buda-govsky series (B.9, B.10), five unreleased Budagovsky clones (B.7-3-150, B. named clone from the Pillnitz series (Supp.3) and on...
Article
Full-text available
In three experiments, diameters of apples representing 7% to 30% of the fruit on a tree were measured at ≈60 days after full bloom. Using previously published regression equations, the early-season fruit diameter values were used to estimate apple fruit weight at harvest (FWH). At harvest, all fruit on sample trees were weighed and the distribution...
Article
Full-text available
Canopies of ‘Gala’ and ‘Fuji’ trees, trained to the vertical axis, were divided into eight vertical sections, each representing 12.5% of the tree canopy. The diameter of all ‘Gala’ fruit and fruit weight for all ‘Fuji’ fruit were recorded for each canopy section. Fruit size from most canopy sections was normally distributed and distributions were s...
Article
Early-season fruit diameter measurements for ‘Gala’, ‘Fuji’, and ‘Honeycrisp’ apples in three orchards for 3 years were used to develop regression models to estimate fruit weight at harvest. Fruit weight at harvest was linearly related to fruit diameter 60 days after bloom, but intercepts and slopes were not homogeneous for all nine combinations of...
Article
Full-text available
Background and aims Root and mycorrhizal fungal foraging in nutrient-rich patches is an energy-intensive process, and shifts in carbon (C) availability may affect foraging strategies. We hypothesize that when trees are C limited, they will prioritize root and mycorrhizal hyphal growth in nutrient-rich soil patches. Methods Apple (Malus domestica B...
Article
Full-text available
Two experiments were performed to study the anatomical traits related to the development of graft unions of relatively weak (
Article
Full-text available
Peaches (Prunus persica (L.) Stokes) are grown in several regions throughout the U.S., are eaten fresh, and used as ingredients in value-added processed products. An Internet survey was conducted to investigate Mid-Atlantic consumers' fresh and processed peach purchasing behaviors, and whether packaging certain numbers of peaches together, providin...
Article
Full-text available
Dwarf apple (Malus spp.) rootstocks with ‘Golden Delicious’ as the scion cultivar were evaluated at eight locations in North America for 10 years. A core of 11 rootstocks was evaluated at all locations. Core rootstocks included four industry standards (B.9, M.9 NAKBT337, M.26 EMLA, and M.9 Pajam 2), along with B.10 (formerly called B.62396) from Ru...
Conference Paper
Full-text available
Application of prohexacione calcium (PC) beginning shortly after petal fall can prevent excessive vegetative growth. Recommended application timing is 2.5 to 7.5 cm shoot length. There is little information about application at later stages The study block consisted of 10th leaf ‘Golden Delicious’ trees grafted onto M.9 T337, M.26 EMLA, and G.16. A...
Article
Full-text available
Two important choices for apple growers are which cultivar to grow and which training system to use. Stochastic dominance analysis was used in an economic evaluation of a 10-year study in Pennsylvania (USA) comparing three cultivars ('Crimson Gala', 'Ginger Gold', and 'Fuji') grown on four training systems (vertical axe, slender spindle, 4-wire low...
Article
'Golden Delicious' apple trees [Malta x domestica (Borkh.) Mansf] on three dwarfing rootstocks (M.9 NA-KBT337, G.16 and M.26 EMLA) were grown at 11 locations and crop densities were adjusted to various crop densities, ranging from 3.0 to 14.0 fruit/cm(2) of trunk cross-section arcs, to determine if rootstock influenced the relationship between crop...
Article
Full-text available
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...
Article
Full-text available
'Golden Delicious' apple trees [Malus x domestica (Borkh.) on three dwarfing rootstocks were grown at 11 locations in North America, and crops were adjusted to varying levels of crop density to determine if rootstock influenced the relationship between crop density and annual trunk growth over a 5-year period. Analysis of covariance was used to eva...
Article
Full-text available
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,...
Article
Full-text available
An experiment designed specifically to evaluate the influence of rootstock on average fruit weight of 'Golden Delicious' apple [Malus x sylvestris (L.) var. domestic(Borkh.) Mansf] was established at 12 locations in North America. Trees on three dwarfing rootstocks (G.16, M.26 EMLA and M.9 NAKBT337) were allowed to fruit for the first time in the t...
Article
Full-text available
Desirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple. The purpose of the present study was to quantify rootstock-medi...
Data
Tables S5-S6. Table S5. Stepwise multiple regression analysis parameter estimates and associated statistics for transcripts with higher expression in less susceptible trees. Table S6. Stepwise multiple regression analysis parameter estimates and associated statistics for transcripts with higher expression in more susceptible trees.
Data
Tables S1-S4. Table S1. Expression patterns of putative phenylpropanoid genes from Malus x domestica. Table S2. Candidate fire blight resistance transcripts with higher expression in 'Gala' scion/rootstock combinations with lower susceptibility to E. amylovora. Table S3. Candidate fire blight resistance transcripts with higher expression in 'Gala'...
Conference Paper
Researchers have collected a great deal of data relating to apple 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 on-line technology available through eXtension (extension.org). In eXtension, researchers an...
Conference Paper
Full-text available
In recent years the apple industry has a seen dramatic change in production systems. New training systems being adopted include the Axe (A) and Tall Spindle (TS), with recent work suggesting that tall narrow canopies that lend themselves to the use of mechanized platforms may be more economical. To evaluate these new systems a planting of ‘Jonagold...
Article
Full-text available
A planting of 'Ginger Gold', 'Crimson Gala' and 'Fuji' (BC#2) on M.9 NAKB T337 rootstock was established in 1997 at the Horticultural Research Farm at Rock Springs in central Pennsylvania, USA. The cultivars chosen represented three distinct growth habits. The trees were trained to one of four training systems; a vertical axe (A), a slender spindle...
Article
Full-text available
In spring, 1999, two trials of dwarf apple (Malus × domestica) rootstocks were established under the coordination of the NC-140 Technical Committee. One trial included 'Fuji' as the scion cultivar, and the other included 'McIntosh'. Rootstocks were CG.4013, CG.5179, Geneva ® (G) 16N (liners from stoolbeds), G.16T (liners from stoolbeds derived from...
Article
Full-text available
'Fuji' and 'McIntosh' apple trees (Malus x domestica Borkh.) on CG.4814, CG.7707, G.30N (liners from stool beds), M.7 EMLA, M.26 EMLA, and Supporter 4 rootstocks were planted at six sites with 'Fuji' and seven sites with 'McIntosh' as the scion cultivars throughout North America as a uniform trial coordinated by the NC-140 Technical Committee. Part...
Article
Full-text available
Fuji' and 'McIntosh' apple trees (Malus X domestica Borkh.) on CG.4184, CG.7707, G.30N (liners from stool beds), M.7 EMLA, M.26 EMLA, and Supporter 4 rootstocks were planted at 19 locations ('Fuji' at 9 sites and 'McIntosh' at 10 sites) throughout North America as a uniform trial coordinated by the NC-140 Technical Committee. After five growing sea...
Article
Full-text available
One hundred forty-nine consumers participated in a sensory evaluation, conducted on 14 Nov. 2008, at The Pennsylvania State University, University Park, PA, to determine consumer acceptance and perceptions of scab-resistant apples (Malus ×domestica). Consumers were exclusively screened for liking and eating apples. The study provides tree fruit gro...
Conference Paper
The purpose of this study was to evaluate four new strains of ‘Fuji’ for growth, production and fruit color. The strains were ‘‘Mira’’, ‘Sun’, ‘BC#2’ and ‘Yataka’. The trees were planted in 1998 on M.9 rootstocks in a randomized complete block with ten replications. At the end of the 2007 growing season the largest trees as measured by trunk cross...
Article
Full-text available
Apple trees (Malus x domestica) do not reproduce true-to-type from seed. Therefore, desirable cultivars are clonally propagated by grafting vegetative material onto rootstocks. Although cloned cultivars are genetically identical, rootstocks influence horticulturally important cultivar traits, including tree size, disease resistance, and abiotic str...
Conference Paper
Full-text available
A plethora of apple rootstocks have been released in the last few years. Many are coming from eastern European countries and were not readily available before. Countries such as the Czech Republic, Germany (formerly East Germany) and Russia have released several new rootstocks. The rootstocks from the Czech Republic are designated the J-TE series;...
Conference Paper
One hundred and forty-nine consumers participated in a sensory evaluation, conducted on 14 Nov. 2008 at The Pennsylvania State University, University Park campus to determine consumer acceptance and perceptions of apple-scab resistant cultivars of apples. The study was conducted to provide Pennsylvania tree fruit growers with a better understanding...
Article
Full-text available
A multi-site experiment to evaluate the performance of 23 apple (Malus x domestica Borkh.) cultivars was established in 1999. The purpose was to evaluate new and promising cultivars and breeding selections in a range of geographical and climatic areas within North America. All trees were propagated on M.9T337 and minimally pruned to encourage early...
Article
Full-text available
The NE-183 regional project was established in 1994 with its primary objective to evaluate horticultural characteristics and pest susceptibility of new apple (Malus x domeslica Borkh.) cultivars and advanced selections at numerous locations throughout the United States and Canada to determine both limitations and positive attributes of these cultiv...
Article
Full-text available
The fruit quality performance of 23 apple (Malus x domestica Borkh.) cultivars and numbered selections on Malling 9 (M.9 T337) rootstock was evaluated over four growing seasons at 12 locations across North America as part of the NE-183 Regional Project, "Multidisciplinary Evaluation of New Apple Cultivars." At each site, trees were planted in 1999...
Article
Full-text available
Fuji' and 'McIntosh' apple trees (Malus X domestica Borkh.) on CG.3041, CG.4013, CG.5179, CG.5202, G.16N (liners from stool beds), G.16T (liners from tissue cultured plants), M.9 NAKBT337, M.26 EMLA, Supporter 1, Supporter 2, and Supporter 3 rootstocks were planted at 19 locations ('Fuji' at 10 sites and 'McIntosh' at 10 sites) throughout North Ame...
Article
In 1998, two multi-site replicated rootstock trials were established by the US national rootstock testing group, "NC-140". The trials compared 2 elite dwarf Geneva apple rootstocks that are tolerant to fireblight and Phytophthora root rot. The first trial used 'Jonagold' as the scion and compared 'M.9' with Geneva® 'G.16' and 'G.41'. It was planted...
Article
In 1994, trees of 'Gala' apple (Malus x domestica Borkh.) on 4 semi-dwarf rootstocks were planted at 20 locations in North America according to the guidelines established for cooperative testing by the North Central Regional Cooperative Project (NC-140). The four rootstocks were P.1, V.2, G.30, and M.26 EMLA. Four of the locations did not receive t...
Article
Eighteen dwarfing rootstocks, including six M.9 clones and two Vineland selections, were compared at 25 North American locations for 10 years. For most response variables, there was a highly significant location x rootstock interaction, so rootstock performance differed greatly from one location to another. The M.9 clones tested in this study had s...
Article
'Fuji' and 'McIntosh' apple trees (Malus x domestica Borkh.) on CG.4013, CG.5179, CG.5202, G.16N (liners from stool beds), G.16T (liners from tissue cultured plants), M.9 NAKBT337, M.26 EMLA, Supporter 1, Supporter 2, and Supporter 3 rootstocks were planted at seven sites per cultivar throughout North America as a uniform trial coordinated by the N...
Article
The ability to analytically differentiate and match intact apple (Malus domestica, Borkh) fruit and fruit juice extracts from different apple cultivars is of interest to the food industry. This study tested the feasibility of detecting the difference among volatile gases evolved from intact 'McIntosh (Buhr),' 'Delicious,' and 'Gala' apples and thei...
Article
The ability of chemical sensors to differentiate and match samples of apple flavors and essences is of interest to the flavor and food industries. This study evaluated the feasibility of using a prototype chemical sensor for the differentiation of apple flavors and essences. Volatile headspace gases from 20 flavors and four essences were measured w...
Article
Full-text available
Appearance and internal sensory quality are important aspects to cultivar adaptation because they influence consumers' decisions in purchasing apples (Malus × domestica Borkh.) for fresh consumption. Our objective was to examine the sensory quality of twenty test cultivars grown at various locations in the eastern United States and in Summerland, B...
Article
Full-text available
A multi-site experiment to evaluate the performance of apple cultivars was established in 1995 with twenty different cultivars. The purpose of the experiment was to evaluate new and promising apple cultivars in a range of geographical and climatic areas within North America. All trees were propagated on M.9 and minimally pruned to encourage early b...
Article
McIntosh' apple trees [ Malus ×sylvestris (L.) Mill. Var domestica (Borkh.)] on five semidwarfing rootstocks (CG.4814, CG.7707, G.30N, M.7 EMLA, and Supporter 4) were planted at 10 locations (MA, MI MN NS 2 in NY ON PA VT and WI) under the direction of the NC-140 Multistate Research Project. After four growing seasons (through 2002), trees on CG.77...
Article
McIntosh' apple trees [ Malus ×sylvestris (L.) Mill. Var domestica (Borkh.)] on 10 dwarfing rootstocks (CG.3041, CG.4013, CG.5179, CG.5202, G.16N, G.16T, M.9 NAKBT337, Supporter 1, Supporter 2, and Supporter 3) were planted at 10 locations (MA, MI MN NS 2 in NY ON PA VT and WI) under the direction of the NC-140 Multistate Research Project. After fo...
Article
Full-text available
Similar to fresh market fruit, producers of fruit primarily destined for processing are interested in reducing costs and labor and increasing efficiency through the use of new pruning and training systems. This study looks at five different training systems established in two commercial orchards and examines the early yields, both on a weight per t...
Article
The fruit quality performance of 19 apple (Malus xdomestica Borkh.) cultivars on Malling.9 (M.9) rootstock was evaluated for four growing seasons at 13 locations across North America as part of the NE-183 Regional Project, "Multidisciplinary Evaluation of New Apple Cultivars." At each site, trees were planted in 1995 in five randomized blocks with...
Article
Full-text available
The performance of three apple (Malus x domestica Borkh.) cultivars ('Braeburn', 'Gibson Golden Delicious' and 'Yataka Fuji') on two dwarfing rootstocks (M.9 T337 and Mark) was studied for five years at multiple sites across North America as part of a large international cultivar evaluation trial. The trees were trained as slender spindles, and arr...
Article
Full-text available
Apple cultivar sensitivity to azoxystrobin fungicide was evaluated over two years. A single application of azoxystrobin at 200 ppm concentration was applied to selected shoots of over fifty different apple cultivars and rootstocks. Treated shoots were then evaluated for phytotoxicity four to seven days later. Cultivars that showed symptoms in one o...