Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
Horticulture
Non Technical Summary
The NC-140 Regional Research Project is designed to address a number of high-priority areas within the North Central Region and in North America. This project seeks to enhance economically and environmentally sustainable practices in temperate fruit production by focusing on rootstocks and root systems. The NC-140 project meets the guidelines presented by the North Central Regional Association (NCRA) in Guidelines for Multistate Research Activities (July, 2010). 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 disciplines in multiple states. Researchers involved in this project have leveraged Federal and state dollars to add significant financial and in-kind resources to address this important 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.With the highly competitive international market, the demand for high quality fruit by consumers, the strong pressure to reduce chemical use, and a need to enhance the economic efficiency of production, tree-fruit growers must look to economically and environmentally sustainable management schemes of production. Growers who want to stay profitable must establish high-density plantings with smaller trees using new cultivars. These high-density plantings cost 10 to 20 times more per land area to establish than lower-density plantings, thus greatly enhancing economic risk. Potential returns of high-density plantings, however, far exceed those of low-density plantings, particularly during the first 10 years. The central component of a high-density system is the rootstock, the part of the tree which provides control of final tree height allowing for closer tree spacing and greater number of trees per land area. As part of the tree, the rootstock influences many factors in addition to tree size, particularly productivity, fruit quality, pest resistance, stress tolerance, and ultimately profitability. However, size-controlling rootstocks are lacking for many fruit crops, and those rootstocks that are available have inherent weaknesses. Past research has successfully identified size controlling and early bearing rootstocks for apple and cherry, but inefficient rootstocks remain a problem for other tree fruits. Continued tree losses due to cold temperature injury, disease, scion incompatibility, and poor soil conditions are an economic cost for the industry that can be ameliorated by improving rootstock choices for growers.Success with new orchard systems depends on reliable recommendations that are based on sustained research. New pome- and stone-fruit rootstocks cannot be recommended unless there is coordinated multi-site research investigating soil and climatic adaptability, root anchorage, size control, precocity, productivity, pest resistance, and propagation. Tree fruits are long-lived perennials, so a minimum of eight years is necessary to obtain an indication of rootstock performance and to accurately assess the potential for improved profitability, reduction of external farm inputs, and enhancement of production efficiency. With ever-increasing use of high density systems, there is a concomitant demand by growers for research that solves problems and for timely information that prevents costly mistakes.A stable tree-fruit industry based on economically and environmentally sustainable orchard systems is one of the primary goals of NC-140 research. Knowledge of rootstock performance has led to research-based recommendations that have been adopted by the industry and have led to increasingly efficient orchard systems. Prior to organization of NC-140, knowledge of rootstock performance and adaptability was obtained from unrelated studies resulting in serious planting and management errors thus a loss in revenue. Evaluating rootstock tolerances to biological, environmental, and edaphic stresses requires uniform, cooperative testing. New rootstocks are quickly and systematically exposed to widely varying soil and climatic conditions to shorten the time necessary for thorough continental evaluation.Any newly developed rootstock must exist as an integrated orchard-management system. Current economic trends make production efficiency of multi-genetic plant combinations in various management systems one of the most important factors that must be evaluated thoroughly before specific combinations are recommended for large-scale plantings by fruit growers. Uniform trials replicated within sites and across varying climatic and edaphic conditions have been established by the NC-140 Committee.Orchard systems, focusing on the rootstock, must be designed to meet the specific needs of each temperate-zone tree fruit crop. One of these needs is the high cost and scarcity of labor. In response, the apple and cherry industries have developed high density orchard systems with a smaller trees and a higher number of trees per acre, with all tree maintenance occurring from the ground using size controlling rootstocks. High density systems were originally developed in Europe with rootstocks adapted to a European climate. Research done by NC140 members demonstrated growth characteristics of rootstocks under North American conditions were different than in northern Europe, with tree responses varying greatly across regions in North America. Meanwhile, rootstock breeding programs have resulted in many new elite selections that may be better adapted to the range of North American environmental conditions. These new rootstocks combined with new management systems require testing under many North American climates and modifications of training and pruning techniques must be developed to match local growing conditions.?
Animal Health Component
33%
Research Effort Categories
Basic
34%
Applied
33%
Developmental
33%
Goals / Objectives
To evaluate the influence of rootstocks on temperate-zone fruit tree characteristics grown under varying environments using sustainable management systems.
To better understand the impacts of biotic and abiotic stresses on scion/rootstock combinations in temperate-zone fruit trees.
To enhance the sustainability of temperate fruit farming through development and distribution of research-based information utilizing eXtension.
Project Methods
Objective 1To evaluate the performance of rootstock material in different climatic and edaphic environments, established replicated uniform trials will be maintained, and new trials will be established across North America as part of the NC-140 project. Promising new and existing rootstocks and multiple genetic systems possessing desirable characteristics have been or will be selected. Evaluation for survival, precocity, productivity, size control, anchorage, suckering, pest resistance, adaptability, and production efficiency will occur.Data will be collected according to specific guidelines established by the technical committee. For each trial, data collected will include root suckering, tree growth as measured by changes in trunk cross-sectional area, tree height, canopy spread, precocity, yield, fruit size, temperature and rainfall/irrigation. Trials will be formally concluded after 10 growing seasons. Designated cooperators will serve as coordinators who will collect and archive data for the life of each trial. Data will be processed and annual progress reports shared with trial cooperators and the full membership at annual meetings. Trials are established by cooperators and coordinated by representatives from PA (2003 apple), CA (2004 pear), CA (2005 pear), SC (2009 peach), MI (2009 cherry physiology), CA (2009 peach physiology), MI (2010 sweet cherry), MA (2010 Honeycrisp apple), MA (2010 Fuji apple), OR (2012 pear), OR (2013 pear), NY (2014 organic apple), SC (2014 apple), MI (2015 sweet cherry), MI (2015 tart cherry), MA (2016 apple), SC (2016 peach, plum, and apricot), and OR (2016 pear). Standard statistical analyses will be performed on all data, and trials will be summarized for joint publications after five and 8-10 years of testing.Objective 2To enhance tree performance and pest resistance, traditional and marker-assisted breeding programs will develop improved rootstocks for apples (NS, NY), cherry (MI), peaches (GA, SC), and pears (WA). Each of these breeding program directors will supply progress reports and updates regarding the results of their work which will be shared at annual meetings with committee members. Where possible and needed, cooperators and members of the committee may serve as second- or third- phase testing sites for confirmation of biotic stress resistance. Eventually, offspring identified as having promise from these programs will enter the uniform trial testing process as described in Objective 1. Additionally, manuscripts or their published citations will be shared with the members at-large, regarding results from these studies.Objective 3Research conducted to improve propagation capability of rootstocks will be conducted at individual institutions. Research directors and committee members involved in these projects will supply progress reports and updates regarding the results of their work which will be shared at annual meetings with committee members. Research results that will enhance propagule availability will be shared with the committee membership and especially those planning future trials where sourcing of propagules is a challenge. Additionally, manuscripts or their published citations will be shared with the members at-large, regarding results from these studies. Proposed research at individual institutions includes the following: (1) improvement of propagation practices and techniques including tissue culture and evaluation of that material in the field (CA, MD, ME, MI, NS, NY, ON, OR, and WA) and the use of layering and cuttings (NY and WA); (2) comparison of ease of propagation of the Weiroot series of cherry rootstocks (Weiroot 10, 13, 72, 158, and 12) with Gi6 and Mahaleb (ON); (3) development of novel nursery production techniques for small-scale, organic apple nurseries (MI); (4) comparison of stoolbed produced and tissue-cultured G.202 rootstocks with Gala and Cripps Pink as scion cultivars (MD); (5) study the use of benzyl adenine and cyclanilide to enhance the production of feathered nursery trees (NY); (6) evaluation of stoolbed management approaches with Geneva apple rootstocks, including source of plant material planting density, planting angle and plant growth regulators (NY); and (7) propagation of the Vineland series of apple rootstock via tissue culture to increase quantities available for U.S. nurseries (ON).Objective 4Studies will be conducted by individual members and cooperators at various institutions to elucidate stress tolerance of fruit trees as influenced by rootstocks. Basic rootstock performance data will be collected as part of the evaluation of rootstocks in the trials listed under objective 1; however, additional, more-detailed studies will be led and conducted by individual cooperators using these rootstock plantings as uniform multiple test sites. Trial coordinators or cooperators will canvas cooperators to determine interest in conducting separate, more detailed studies on a specific parameter. Those leading the effort will supply progress reports and updates regarding the results of their work which will be shared colleagues collecting the data and information and it will be shared with the full membership at annual meetings. Additionally, manuscripts or their published citations will be shared with the members at-large, regarding results from these studies. Stress-related studies will include the following.Low-temperature stress: (1) assessment of the effects of various rootstocks on low-temperature susceptibility of peach flower buds (MO); (2) evaluation of the influence of apple rootstocks (B.9, M.9 and M.27) and scions (SunCrisp and Fuji) on blackheart injury and determine the relationship between blackheart and fruit yield (MO); (3) determine the cold hardiness of rootstocks and the influence of rootstock on scion cold hardiness for apple (IA, ME, MI, MN, ON and UT); (4) evaluation of peach rootstocks on cold hardiness (UT); and (5) evaluation of cold resistance of quince rootstock for pear (OR).General climate, water, nutritional, and physiological stress: (1) study the relationship between rootstock, soil, climate, moisture and nutrient uptake (BC, VA); (2) evaluation of the relationship of rootstock, nutrient uptake and fruit quality (ID, VA); (3) evaluation of peach and apple rootstocks on alkaline soil (UT); (4) evaluation of tart cherry rootstocks with and without irrigation (WI); (5) evaluation of cherry rootstock effects on water and nutrient relationships (MI); (6) development of climate-modifying systems, such as high tunnels in cherry and other stone fruit and the relationship to rootstocks (MI); (7) evaluate the impact of rootstock/scion combinations on fruit sunburn and crop load management (OH); (8) methods will be developed to connect bioassays for biotic and abiotic stresses with transcriptomics approaches for identification of genes-associated with the process of stress manifestation (WA); (9) transcriptomics datasets will be mined for allelic diversity of stress-related genes facilitating gene-assisted selection for breeding of improved crops (WA).Objective 5In 2010, an eXtension Community of Practice (CoP) was funded through USDA-SCRI, and initiated to assemble the vast quantity of apple-related information developed by NC-140 and other apple-related research. The Apple eXtension website launched in September 2011. This novel vehicle for information collection, organization and delivery will be developed further during the period of this project.