Date of NC-140 Annual Report: 01/06/2015

Report Information:


Brief Summary of Minutes of Annual Meeting:


Impact Nuggets

Knowledge gained on 14 peach rootstocks tested under Alabama environmental conditions will help to sustain the peach industry with a long-term economical impact in increased yield efficiency and survival. New dwarfing peach root continue to demonstration excellent potential in CA. Oak root rot continues to hamper sweet cherry rootstock trial in CA. Detailed and objective evaluation of new rootstocks in NC 140 trials has provided KY growers with the information needed to select the most appropriate rootstocks for their needs as they become commercially available. Planting of 200 acres of trees in MA on dwarfing rootstock occurred during 2014 based on results of NC-140. On this acreage, pruning and harvest labor declined by 50%, fruit quality and size increased by 20%, profit increased by 50%, and because of reduced canopy volume, pesticide use declined by 70%. The demonstration of precocious yields and labor efficiencies with novel high density “fruiting wall” training systems for sweet and tart cherries has stimulated global, North American and commercial grower orchard trials in Michigan. The uniform apple rootstock trials in MN have allowed growers in USDA hardiness zone 4 to evaluate new rootstocks for planting in commercial operations. Through Rutgers Cooperative Extension outreach, 98% of all New Jersey orchards use apple, pear, peach and cherry dwarfing rootstocks as a direct result of NC-140 research and extension over the past 30 years. New disease resistant dwarf and semi-dwarfing apple rootstocks from the Geneva apple rootstock-breeding program which are being evaluated in NC 140 are being planted by growers in New York. These new Geneva rootstocks should provide fresh and processing growers with greater tolerance to rootstock fire blight and greater economic success with new orchards. NC 140 trials conducted in Nova Scotia have provided growers with extra information for selection of rootstocks for new Honeycrisp apple plantings. Sweet cherry and pear trials have provided confirmation to growers of length of time to achieve yields and challenges with production in Nova Scotia. NC-140 plantings are regularly used as demonstration plots for visiting apple growers, nursery operators, extension personnel, and research scientists in Ontario, Canada. The research data collected in these trials help to establish base-line production and economic records for the various orchard system/rootstock combinations that can be used by orchardists in Ontario. Several European peach rootstocks on trial in NC 140 have been found to be non-adaptable to South Carolina’s soil pathogens and/or climate conditions. NC 140 rootstock trials have been critical to growers in Utah in seeking peach rootstocks which are more tolerant of alkaline soils and in moving away from Lovell and Nemaguard standard rootstocks. Wisconsin apple growers are showing increasing interest in the planting of super spindle and tall spindle systems. Results from past and current NC140 trials in Wisconsin have been critical in demonstrating the productivity of dwarfing rootstocks and their applicability in high density planting systems.

New Facilities and Equipment

An upgraded apple fruit washing and packing line was installed in NJ, including a donated bin dumper, at the Rutgers University Snyder Farm. A peach orchard systems trial (not part of NC140) was planted in 2014 based partially on data from the 2009 NC140 trial. Plant cameras were installed to continuously record tree growth under different training systems in the 2013 pear trial. Mid-day stem water potential (MSWP) is measured weekly using pressure chambers for the 2005 and 2013 pear trials. Light interception is measured annually using a light bar mounted on a Kawasaki Mule in the 2013 pear trial. A series of 21 trail cameras were established to capture hourly images of Golden Delicious/G.16 trees associated with fruit growth and development. During the 2014 growing season, over 100,000 images have been collected. In addition, a deer fence was installed to protect fruit plantings at the Purdue University’s Meigs farm. A deer fence was installed in 2014 to protect the orchard plantings in KY. The ORSI Cross model self-propelled, self-leveling platform was deployed in ME to study harvest and pruning labor efficiency in high density trials. Orchard climate modification systems (automated retractable roof, manual row covers) were tested to protect high density sweet cherry trees from frost, rain, wind, hail, birds, and some diseases in plots in MI. During 2014, a multi-plate modular differential thermal analysis (DTA) system was built for evaluating peach bud hardiness in UT.

Unique Project Related Findings

Low survival rates by the end of the fifth season were recorded in AL for peach on Mirobac and Krymsk®1 rootstocks. Trees on Empyrean®2 also had low survival. Guardian®, Lovell, KV010-123 and BH-5 grafted trees had 100% survival. Fire blight losses of trees on M.9 and M.26 rootstocks in NC 140 trials in KY offer further confirmation concerning current extension recommendations to growers with regards to these two rootstocks. Peach on Prunus americana continues to be the most productive dwarfing rootstock in a NC 140 trial in MA, equaling the per-tree productivity of standard rootstocks and producing fruit of comparable size. MSU-developed cherry rootstock selections exhibit vigor reduction and precocity comparable to Gisela 3 and Gisela 5 rootstocks for tart and sweet cherry scion varieties in preliminary trials in WA and MI. Preparations have begun to include these in 2017 NC140 coordinated comparative trials for sweet and tart cherry. Krymsk® 1 rootstock reduced peach tree vigor by 40% as compared standard Lovell rootstock in Missouri. The problems of tree survival in high winds of Cripp’s Pink on G41and G935 in MD were unexpected and point to the need to test a wider range of new cultivars, especially in southern areas with longer growing seasons. In the 2010 apple trial in NJ, 14 new rootstocks had equal or greater cumulative yields than the standard dwarfing stock, M9-337 from 2012-2014 including 8 CG stocks from the Cornell breeding program. B.9, the most popular rootstock in Ohio, is not vigorous enough to fill the space in the tall spindle system in year 5 with Honeycrisp as the scion. Sixteen new Prunus rootstocks released for peach were field screened and after 6 years of testing, several are comparable to commercial standards, Lovell and Guardian® in SC. During the severe winter of 2013-14 in WI, multiple events of low winter temperature, coupled with high solar flux, resulted in southern trunk exposure damage. This allowed for southwest trunk injury (SWI) ratings to be recorded.

Accomplishment Summaries

Objective 1. To evaluate the influence of rootstocks on temperate-zone fruit tree characteristics grown under varying environments using sustainable management systems.

Projects in various stages of data collection, evaluation and planning include the following in association with years of plot establishment and identification of trial coordinators ():

2003 Apple Physiology (Rich Marini) 2003 Dwarf Apple Rootstock (Rich Marini) 2005 Pear Rootstock (Rachel Elkins) 2009/2014 Peach Physiology (Rich Marini) 2009 Peach Rootstock (Greg Reighard) 2010 Apple Rootstock (Wes Autio) 2010 Sweet Cherry Rootstock and Training Systems (Greg Lang) 2013 Pear Training/Rootstock/Spacing (Todd Einhorn) 2014 Apple Rootstock (John Cline) 2015 Organic Apple Rootstock (Terence Robinson) 2016/17 Tart Cherry Rootstock x Harvest System (Matt Stasiak/Greg Lang) 2016/17 Sweet Cherry Rootstock (Greg Lang) 2016/17 Pear Interstem/Quince Rootstock (Todd Einhorn) 2018 Apricot Rootstock (Terence Robinson)

• Apple Sub-Committee (Chair, Terence Robinson, NY)

The 2003 Dwarf Rootstock Trial was established in the spring of 2003 with 15 cooperators. During the past several years seven cooperators dropped out for various reasons. All eight remaining cooperators received trees on 11 core rootstocks; four of cooperators received an additional seven rootstocks; and two cooperators received 12 additional rootstocks. The scion cultivar is ‘Gibson Golden Delicious’. Each cooperator received 8 trees per rootstock for most rootstocks, but most got only 7 trees of 5 rootstocks and three got only 6 trees of one rootstock. At each location the experimental design was a generalized randomized complete block design with 2 trees of each rootstock randomized within each of 4 blocks per location. Trees were trained to the Vertical Axis system. The 10-year summary was published in the April 2014 edition of the Journal of APS. Conclusions are: 1. CG.3041and CG.5935 are candidates to replace M.9 because it had better tree survival in locations where East Malling rootstocks typically have high tree mortality and had YE (Yield Efficiency) higher than or equal to M.9. CG.3041 was slightly less vigorous than CG.5935 at most locations. 2. Based on results from only two locations, CG.5179 is in the M.9 size class, but did not perform better than M.9 NAKBT337 in terms of tree survival or YE. 3. B.62396 had good tree survival, and high YE and should be evaluated further as a potential replacement for M.9. 4. Based on tree survival and YE, J-TE-H should be evaluated further as a possible replacement for M.26. 5. CG.6210 is similar in vigor to M.26, with similar tree survival, but higher YE. CG.6210 may be a replacement for M.26, but CG.5935 seems even better. 6. CG.5179 was evaluated at only two locations, and performed similar to M.9 and should be evaluated further.

For the 2003 Apple Physiology Trial, Golden Delicious on three rootstocks (M.26 EMLA, M.9 NAKBT337 and G.16) was planted at 12 locations in 2003. At each location there were 10 trees per rootstock in a completely randomized design. Each year when there was adequate bloom, two trees per rootstock were thinned to various crop densities (CD). Each year trunk cross-sectional area (TCA), yield, number of fruit, and bloom density were recorded. Three papers were published in the Journal of the American Pomological Society to evaluate the effect of location and rootstock on the relationship between CD and average fruit weight (FW), annual trunk growth and return bloom. These data were reanalyzed for a presentation for the ISHS symposium in Geneva, NY. The focus of this study was to determine the interactive effects of early season temperatures, crop density and rootstock on average fruit weight. The summary of the results that will be published in Acta Hort. Are as follows: 1. Over the 7-years of the trial crop density (CD) ranged from 1.0 to 15.0 fruit/cm2 and growing degree days (GDD) during the first 60 days after bloom varied from 445 to 780. 2. The 3-way interaction of rootstock x CD x GGD2 was significant (R2 = 0.42, P <0.0001) so models were developed for each rootstock. 3. FW was negatively related to CD and there was a quadratic relationship for GDD. For G.16 and M.9, FW peaked at 650 GDD, but for M.26 FW peaked at 700 GDD. 4. FW increased at a greater rate with increasing GDD for heavy-cropped trees than for light-cropped trees. For all rootstocks, FW was most affected by CD at low values of GDD.

The 2010 NC-140 Apple Rootstock Trial includes 10 Budagovsky, 16 Geneva, 3 Pillnitz, and 3 Malling (controls) rootstocks. Fourteen locations use Honeycrisp as the scion cultivar, and 7 locations use Aztec Fuji. All trees were supported to approximately 3.5 m and grown as Tall Spindles. At the end of 5 growing seasons and across all locations, the largest Honeycrisp trees are on B.70-20-20. This rootstock results in a tree much too vigorous for high-density planting. The smallest trees are on B.71-7-11. This rootstock results in a Honeycrisp tree which is too weak for commercial use. Yield efficiency did not vary greatly among rootstocks, except that the most vigorous (e.g., B.70-20-20) are very inefficient. Fruit size has been good for all Honeycrisp trees in this trial, except for those from trees on PiAu 9-90. In the Fuji trial, some trees were lost in the first season due to damage in the nursery, but since that time, trees have grown very well. At the end of 5 growing seasons, largest Fuji trees were on B.70-20-20 and the smallest were on B.71-7-22. As with Honeycrisp, both rootstocks would be consider unacceptable. Generally, yield efficiency was negatively related to tree size. Fruit size was relatively consistent, except fruit from trees on B.7-20-21 were much smaller than those from all others.

The 2014 Apple rootstock planting was established in 15 locations in the United States (AL, ID, IN, MA, ME, MI, MN, GA, NJ, NY, PA, UT, VA, WA, WI), two in Canada, and one in Mexico ( The trial consists of the following rootstocks: B.10, G.11, G.202, G.214, G.30, G.41, G.5890, G.935, G.969, M.26 EMLA, M.9 T337, V.1, V.5, V.6, V.7. The trial is being coordinated by John Cline who has also agreed to analyze the data. This trial has two cultivars: Aztec Fuji (AL, ID, GA, NJ, ON, PA, UT) and Honeycrisp (ID, IN, MA, ME, Mexico, MI, MN, NJ, NY, Ontario, PA, VA, WA, WI), planted to a ‘tall spindle’ systems at a 5 x 12 feet, and 4 x12 feet spacing, respectively. Trees are planted using a randomized block design with single trees serving as experimental units. Each site selected a pollinizer variety since some sites are very limited in adapted varieties. Trees were established in the spring of 2014. The trees were propagated by Willow Drive Nursery, WA. Data protocols have been established for 2014 and 2015. In 2014, the following data were recorded: 1) initial trunk diameter measured at planting 30cm above graft union; 2) number of side branches >10 cm at planting; 3) trunk circumference in the fall of 2014; 4) height of the graft union above soil; 5) tree status at the end of the 2014 growing season.

For the 2015 Organic Apple Rootstock Trial, trees have been dug at Wafler Nursery. The trial will be planted at 14 locations and will evaluate 9 Geneva rootstocks and 1 Malling rootstock. Modi is the cultivar and Liberty will be the pollenizer. The design is five blocks in two-tree sets and will require 1/10 acre. Organic certification is optional, but orchard management must be organic. Land does not have to be organically certified prior to planting.

• Cherry Sub-Committee (Chair, Greg Lang, MI)

The 2010 Sweet Cherry Rootstock x Canopy Training System Coordinated Trial began with 13 sites; these have dwindled to 5 due to diseases, cooperator retirements or transitions, deer damage, etc. Work has begun on the first trial paper (Training Systems Establishment, Years 1-4) with adequate data expected from CA, MI, NY-Geneva, NY-New Paltz, NS, and BC. Of this group, CA likely will drop out for the next phase (Initial-Maturation Yields – Years 5-8) due to excessive mortality from Armillaria. Yields are highly variable by site and lots of lost data because of birds, deer, Armillaria, frost damage, bacterial canker, and trial coordinator retirements. Since most training systems under test are new and novel, questions about proper training and pruning with respect to the spacing and range of rootstock vigor in the trial – perhaps some excessive shading causing some yields to diminish.

Two 2010 Tart Cherry Rootstock x Canopy Training System Independent Trials were established in UT (Brent Black) and MI-Traverse City (Greg Lang/Nikki Rothwell/Ron Perry). The focus is on examining rootstock x canopy training interactions to develop hedgerow-type trees for over-the-row mechanical harvest. Gi.3 was about equal to Gi.5 in adaptability, which were better than Gi.6 and all were better than Mahaleb.

For the 2016 Tart Cherry Rootstock x Harvest System, Matt Stasiak (WI) will be the trial organizer, while Greg Lang will organize tree procurement and the trial will be pushed to 2017 because of nursery issues. The trial will have 5 Michigan State rootstocks, 3 Gisela stocks (3, 5, 12), Krymsk 6, and Mahaleb. Trial sites are UT (2), WI (2), ON, MI, NY, and possibly PA and MD. The tart cherry trees will be trained for over-the-row mechanical harvesting. For the 2016 Sweet Cherry Rootstock coordinated by Greg Lang (MI), it will be pushed back to 2017 because of nursery issues. It will have 5 Michigan State rootstocks, 3 Gisela stocks (3, 5, 12), Krymsk 6, MxM14, and possibly some WeiGi stocks (originated from Gisela program with advanced selections sent to Weihenstephan research station; working with a Dutch nursery). Trial sites include OR, CA, WA, ID, MI, NY, and BC with Benton as a scion. Trees will be trained as 2 or 3 systems at each site.

• Pear Sub-Committee (Chairs, Todd Einhorn, OR; Rachel Elkins, CA)

For the 2005 Pear Trial coordinated by Rachel Elkins, a summary of the original nine trials (Sacramento Delta (Bartlett) and North Coast (Bartlett, Bosc), CA; Chihuahua, Mexico (Bartlett); Hood River, OR (Anjou); Geneva, NY (Bartlett, Bosc); Cashmere, Tonasket and Yakima, WA (Anjou, Bartlett, Bosc), shows six completed the entire 10 year duration: one Anjou (OR), three Bartlett (CA, MX, NY), two Bosc (CA, NY). The others were abandoned for various reasons upon decision by the cooperators, but five-year summaries were published in Acta Hort (2010). 2005-2013 results were presented at the ISHS Pear Symposium in Leuven, Belgium. Data from 2005-2014 will be summarized for the Journal of the American Pomological Society. Based on results from CA, NY and NY, OHXF 87 performed best for very vigorous, non-precocious Anjou. For less vigorous, more precocious Bartlett, results differed by site: the vigorous but precocious Horner 4 was best on California’s warm North Coast based on consistently large fruit size with Pyro 2-33 also quite acceptable but with somewhat smaller fruit. The less vigorous Pyro 2-33 was best in cooler NY. Season-long mid-day stem water potential measurements suggest that Horner 4 maintained good water status during the hottest and driest summer months while the less vigorous rootstocks were stressed, which may partially explain these varying results. For Bosc, of intermediate precocity, OHxF87 was best in CA and WA (Horner 4 was least efficient due to excessive vigor) but was not tested in NY where 708-36 had the highest yield efficiency in NY. Based on this trial, Horner 4 trees are being propagated by commercial nurseries for wider trial planting as replants (vigorous but also precocious) and for semi-high density plantings. OHxF 87 and Pyro 2-33 are also being planted, along with OHxF 97, the standard replacement for Winter Nelis and P. betulaefolia. The committee will determine potential further data collection possibilities for the existing 2005 trial trees, e.g. water relations measurements and crop load adjustment.

The 2013 pear training/rootstock/spacing trial coordinated by Todd Einhorn just completed its second season. Cooperators are OR (2 sites; Bartlett and Anjou), NY (Bosc), and CA (Bartlett). Trees were grown by Willow Drive Nursery in WA. Data were confounded by different variables namely three rootstocks: OHxF87, OHxF69, Pyrodwarf 233; three training systems: Upright V; Bi-Axe (Bi-baum); Central Axe; and three spacings: 3, 4.5, and 6 feet. Due to the tighter spacing , the spaces were filled by the 2nd leaf. Data still being organized, but Pyrodwarf 233 is smaller than OHxF69 + OHxF233. Bi-Axis trees have smaller TCSA than single axis trees and there are no differences in spacing so far.

The planned 2016 or 2017 Quince Interstem Trial by Todd Einhorn is still in its initial stages. This new trial consists of quince selections that were tested for freezing tolerance. Suggested spacing is 1-1.5 m x 3.5 - 4 m. Standards would be all commercially available Quince (A, C, BA29) and OHF87. The trial will be looking for cold hardy candidates and 22 are thought to be as hardy as OHxF. The original trees were in micro-propagation when they got infected with thrips so a 2nd try at micro-propagation of 15 cultivars is in the works with Richard Bell doing fireblight tests. Also, Amelanchier rootstocks might be available. Interested states include CA, NY, OR, NS, and WA.

• Peach Sub-Committee (Chairs, Greg Reighard, SC; Rich Marini, PA)

The 2009/2014 Peach Physiology Trial was originally coordinated by Scott Johnson to evaluate the effect of early-season temperatures on fruit weight for trees with light crops, and those data have been published. At the 2013 NC-140 meeting the group decided to continue the trial to study the interactive effects of early-season temperature, cultivar and crop density (CD) on average fruit weight. Five cooperators (Elina Coneva, Essie Fallahi, Mike Newell, Greg Reighard, and Dwight Wolfe) expressed interest in participating. There are 10 single-tree replicates of three cultivars (Redhaven, Cresthaven, Crimson Lady) at each location. Trees were thinned early in the season to develop a range of CDs and days from bloom to harvest, averaged fruit weight and growing degree days were recorded. A preliminary look at the 2014 data from the two locations indicates that at South Carolina, the interaction between CD and cultivar was not significant (0.31), but the slopes were -19, -13 and -32 for Cresthaven, Crimson Lady and Redhaven. R2 values were 0.44, 0.72, and 0.71, respectfully for the same cultivars. Maryland did not have Crimson Lady and the cultivar x CD interaction was not significant (P=0.32) indicating that the slopes were not different. However, slopes were 0.76 and -134 for Cresthaven and Redhaven, respectfully, and these slopes did not significantly differ from zero. The reason that these seemingly different slopes were not significantly different was because there was great variation in the data and the R2s were only 0.0001 (P=0.994) and 0.2 (P=0.189), respectively.

In the 2009 Peach Rootstock trial, there were significant differences in tree size, survival, yields and yield efficiency among rootstocks within and across 13 locations. Generally, peach seedling rootstock cultivars were the most productive except in high pH soils where hybrids have performed better. Prunus persica and almond hybrids produced the most vigorous trees in all locations. Dwarfing rootstocks included Krymsk®1, Prunus americana and Controller 5. Tree mortality varied greatly with site, but plum species rootstocks, Imperial California, Mirobac, Tetra, and Krymsk®1 tended to have more tree death at some sites.

Objective 2. To develop improved rootstocks for temperate-zone fruit trees using state-of-the-art genomic tools in breeding programs.

Rootstocks from the California peach breeding program have been patented and released with several released in 2014. The Geneva NY apple rootstock program released one new rootstock in 2014. Quince selections in OR are being screened as potential size-controlling pear rootstocks. Pyrus germplasm was established in a collection in WA to evaluate for size control, disease resistance and abiotic stress tolerances of pear trees. Germplasm will also be used for future pear breeding. Field testing of elite cherry genotypes continued in WA and MI. Peach rootstocks are being developed with marker-assisted breeding in South Carolina and conventional breeding in Georgia to reduce impact of Peach Tree Short Life decline for the Southeastern U.S. The Pear Genomics Research Network (PGRN) was formed and accompanying website created,, that will be updated as research progresses (OR, WA, CA). A cherry rootstock selection program at MSU has identified 5 elite genotypes, Cass, Clare, Lake, Crawford, and Clinton, from the sour cherry scion breeding program, that confer significant vigor control, precocity, and high productivity to sweet and tart cherry scions. These are being propagated for widespread future NC-140 coordinated evaluation (MI). The Geneva, NY apple rootstock program released one new rootstock, G814. A paper was published on shoot regeneration in Guardian® rootstock for adaptation to in vitro regeneration systems in peach in SC. UT has received salt tolerant stone fruit rootstock progeny from IPPFBE for testing in trials. Genomics and transcriptomics approaches are being tested in WA to understand rootstock/scion interactions to ensure the compatibility of new rootstocks.

Objective 3. To accelerate adoption of new rootstocks (a) by improving propagation techniques and (b) by acquiring new rootstocks from worldwide sources.

In New York, the propagation of several Geneva rootstocks has been improved significantly by the use of tissue culture plants as mother plants for stoolbeds, especially with G.41. This has resulted in a mini-boom of planting of Geneva 41 stoolbeds. We estimate that 150,000 feet of stoolbeds of G.11 and G.41 and about 50,000 feet of G.935 have been planted. This has resulted in a production of 1.0 million liners of G.11 in 2014 and 1.5 million liners of G.41. Cornell had signed licenses with several additional rootstock producers in 2014. Licensed rootstock producers of Geneva® rootstocks are: Willow Drive Nursery, Willamette Nursery, Treco Nursery, Kit Johnston Farms, Copenhaven Nursery, Cameron Nursery, Gold Crown Nursery, KCK Farms, VanWell Nursery, Helios Nursery, ProTree Nursery, North American Plants, Mori Nursery, Ontario Canada and Viveros Sacramento, Chihuahua, Mexico. In Washington, Stefano Mussachi (WA) is introducing 13 out of 32 dwarfing pear genotypes from the breeding program at the University of Bologna, Italy. They are being processed in vitro through the National Clean Plant Network at Prosser. They would be released after 2 years (2016). The CA and PNW pear industry funded research to improve top and root growth of multiple potential clonal rootstocks using improved nutrient complexes. Results are being made available to nurseries. Several Prunus rootstocks have been sourced from Europe for peach, sweet cherry and tart cherry research in ONT, Canada.

Objective 4. To better understand the impacts of biotic and abiotic stresses on scion/rootstock combinations in temperate-zone fruit trees.

Biotic stresses. Apple rootstock tolerance to replant disease continues in NY to categorize 36 genotypes as resistant, intermediate or susceptible. The 2006 apple replant trial continued in some sites. A 2006 apple fumigation trial in NJ and MA continued. A 2009 peach replant study continued in NC. Russian and Geneva apple rootstocks were evaluated for fireblight tolerance in NY. In VA, 10 rootstocks showed differing susceptibility when inoculated with fireblight bacteria. Research is being conducted on regional and rootstock differences in apple cultivar volatiles and their impact on apple maggot and apple sawfly host selection at NS, Canada. Studies are beginning in VA to plant a test of rootstock susceptibility to Tomato Ring Spot Virus. Gi3 was more susceptible to colonization with root lesion nematodes than Gi5 and Gi6 trees. Peach Tree Short Life decline can be attenuated using rootstocks that can prolong tree and orchard life in GA and SC.

Abiotic stresses. Evaluation of peach rootstock tolerance to soil alkalinity continued in Utah. Apple rootstock tolerance to soil pH is also being evaluated in NY. Cold Hardiness Testing of Apple Rootstock Cultivars and Selections (Collaboration with USDA ARS Geneva and the Univ. of Guelph) is continuing in ME. Cold hardiness of quince selections for pear continued in OR. In IA and MO, a study to determine the relationship of blackheart and tree performance continued. Rootstock treatments affected tree and/or bud survival in the 2009 peach rootstock trial in SC, MO and UT due to cold winter temperatures. Nutritional studies are finding differences among cherry rootstocks in BC. Mineral nutrient absorption is being studied in ID among apple rootstocks. Studies being conducted on UT on iron deficiency in peaches utilizing the 2009 NC 140 peach rootstock trial to see if rootstocks influence iron levels in plant tissue of Redhaven scion. ‘Honeycrisp’ trees on 31 different apple rootstocks showed different abilities to acquire macro and micronutrients in BC, Canada. Cold hardiness was measured in a collection of Geneva and Vineland apple selections, and in several cultivars in October, January and April in ME. The level of cold hardiness in Oct., Jan. and April was determined in 18 apple cultivars and selections in order to identify genotypes likely to result in tree deaths. Nutrient acquisition and partitioning to foliage in ‘Honeycrisp’ apple was examined in 2014 across the range of rootstocks in the 2010 NC140 trial; results currently are being analyzed and interpreted at MI. With minimum winter temperatures in MN of-30C, in the 2010 uniform planting with Honeycrisp as the scion, all rootstocks survived and produced fruit in 2014. Peach rootstocks provided differences in cold hardiness of scion tissue MO and UT. Apple Replant Trials with Gala in NC demonstrate that M.7 survival and performance is superior in fumigated replant sites. Apple rootstocks with weak unions were vulnerable to severe damage following damage caused by Hurricane Arthur in NS, Canada. Peach rootstocks were evaluated and found to differ in survival following the very wet 2013 season and cold winter of 2013-2014 seasons in SC. Tomato Ringspot Virus susceptibility is being studied in a VA NC 140 apple rootstock trial. Cold injury of apple scion tissue was evaluated in WI following the winter of 2013/14. Cold hardiness studies are being studied of quince trees as rootstock candidates in OR.

Objective 5. To enhance the sustainability of temperate fruit farming through development and distribution of research-based information utilizing eXtension.

Members of our research group have been working on making research-based information available to anyone who would like to use it through eXtension (MN, PA, MA, NY, NC, MO, OH, WV, IN, VA). We completed our databases for apple rootstocks and cultivars and can be viewed at at This project was funded through the USDA-SCRI program and was completed in August 2014. We have linked to the primary website for the research group, This site continues to be our primary outreach component serving as an important collaboration tool for cooperators. Members of the research group communicate through a list serve, and upload/download project files to password-protected directories (NJ, MA). We have used the site to allow for easier collaboration and comparison of replicated rootstock trials. Reports, presentations, and videos that update NC140 cherry, apple, and stone fruit rootstock research and extension at MSU are regularly posted on,, and The NC-140 web site, continues to be our primary outreach component serving as an important collaboration tool for cooperators. Members of the research group communicate through a list serve, and upload/download project files to password-protected directories (NJ, MA). Requirements for web page design for regional projects have been met as outlined by the NIMMS and the North Central Regional Association of Agricultural Experiment Station Directors (NCRA). Articles, photographs and reports were archived throughout the year. In 2014, there were 3,868 unique visitors with 5,719 page views. Countries accessing in order: USA, Mexico, Canada, China, Chile, Germany, Iran, India, Turkey, Ukraine, Australia. NC-140 also maintains its own Email distribution list for internal communication. The posting Email address is


Impact Statements:

  1. Official Statement SAES-422: Over the last 30 years, fruit growers in North America have steadily transitioned from large canopied orchards to newer higher density orchards that use less land surface, increased production efficiency, and accommodate automation utilizing new technology in management. New rootstocks have largely been the impetus behind this transition as identified by NC-140 research in identifying superior performing rootstocks, their propagation and commercialization. The outcome of this work has given consumers supplies of sustainably grown quality fresh and processed fruit.
  2. The NC-140 plantings are regularly used as demonstration plots of new rootstocks for growers, nurserymen, visiting scientists, and graduate students. Rootstock trials have also been conducted on grower’s farms that have yielded invaluable information on adaptability that was not known from experiment station trials. Over the last 20 years, there has been a significant change in rootstock use in the United States and Canada.
  3. Results from NC-140 research continue to accelerate the process of identifying superior performing tree rootstocks and of their propagation and commercialization. Growers in various regions of the North America have benefited by having these rootstocks made available earlier by nursery companies. The NC-140 cooperative plantings have identified the benefits of the disease resistant CG rootstocks for North American sites.
  4. Documents have been uploaded in eXtension associated with rootstocks and apple varieties have become a very popular resource for information for growers throughout the eastern United States (MN, NC) found at