NE1014: Development of New Potato Clones for Improved Pest Resistance, Marketability, and Sustainability in the East
Statement of Issues and Justification
Introduction. Potato production in the East spans a diverse set of growing environments, pest complexes, and markets. Potato growers in the eastern United States and Canada need better-adapted, pest-resistant cultivars to serve the large and diverse markets in the region. Maintaining the growers' profitability while achieving improvements in yield and/or quality, and reducing negative environmental impacts is a major goal of this research. Potato production involves the use of many types of chemicals, such as fertilizers, insecticides, nematicides, fungicides, herbicides, vine desiccants, sprout inhibitors, and disinfection agents. Growers and the public will benefit from reduced chemical use. One of the most effective ways of reducing chemical use in potato production is through the development of new cultivars with improved pest resistance, natural sprout suppression, and proper vine types for timely maturation.This project addresses the needs of the eastern potato industry through a coordinated process of potato breeding, selection, evaluation, and variety development. The project includes potato breeding and germplasm improvement within four U.S. programs (Maine, New York, North Carolina, and USDA-ARS-Beltsville). Selection, evaluation, and variety development takes place within a coordinated process among eight eastern states. These collaborative research efforts also include breeding programs and trial cooperators in eastern Canada (Agriculture Agri-Food Canada and provincial programs). The development of new potato cultivars is difficult and takes place in three major steps. First, the breeding programs generate segregating populations and evaluate them for a few important traits in close cooperation with one or more research programs. Second, superior progeny from these populations are identified and evaluated for additional economically important traits under a wide range of environmental conditions. Third, commercial-scale trials are established for the most promising lines and production recommendations are developed prior to cultivar release. The regional project described in this proposal is designed to carry out the above research and development activities in an efficient, coordinated process. The specific objectives are to: 1) Use traditional and molecular breeding approaches to address economically significant production constraints of potato in the East; 2) Develop high quality, pest-resistant varieties for fresh market, specialty, and/or processing use; and 3) Identify and quantify significant climatic and cultural effects on the performance of potato selections.
Importance of Eastern U.S. Potato Production. Potatoes rank amongst the top three vegetable crops produced in FL, ME, NC, NY, OH, PA and VA (USDA NASS 2000). Potato is also a significant portion of the diversified vegetable industries in many other eastern states. Cash farm receipts for eastern potatoes during 1999 were approximately $400 million and multiplier effects in the state and regional economies are many times this amount (USDA NASS, 2000). Production occurs under an extremely wide range of production and marketing conditions, ranging from the winter crop in southern FL to the fall storage crops of ME, NY and PA. This range of conditions creates a tremendous diversity in varietal needs. Due partly to the large population base in the East, fresh market production remains a significant part of the potato industry of most eastern states (e.g. 27% of ME's and 60% of PA's 2000 crop); however, almost 34 percent of all potato chip plants are located in the Eastern or Southeastern U.S., and they account for 38 percent of all chips produced nationwide (NPC Potato Statistical Yearbook, 1999). French fry production is expanding in ME and accounted for 48% of utilization during 2000. ME and NY maintain relatively large, high quality seed potato industries which service most of the East's seed potato markets. Research aiding the eastern potato industry impacts markets associated with over half of the U.S. population. Consumers benefit from the release of new potato varieties that facilitate efficient production for fresh market, chipping, and other processing markets in the East. Improved pest resistance should reduce the need for pesticides and agriculture's impact on the environment.
Need for High Quality, Improved Cultivars for Fresh Market. Attractive, bright, blemish-free appearance is a key need for modern fresh market varieties. New varieties are needed that combine attractive appearance, high yields, uniform size distribution, moderate specific gravity, good pest resistance, and excellent boiling and baking quality. Combining resistance to late blight and scab with high-yielding, round-white table selections in the eastern potato breeding programs will also be important for future development of the fresh market potato industry. Resistance to bruising during harvest and handling is essential. Ideally, varieties will be produced that are visually distinct and of such high quality that identification by variety in the market place will expand growers' marketing opportunities.
A premium-priced market exists for red-skinned and novelty varieties. For reds, the skin color needs to be very bright and stable in storage. Resistance to skinning, netting, and silver scurf are especially important. Novelty varieties (e.g. fingerlings, purple-skinned, blue-skinned, and multi-colored-flesh types) are growing in popularity in the high-value, direct-sale market. Better-adapted novelty varieties would offer new marketing opportunities to many eastern growers.
Need for High Quality, Improved Cultivars for Processing Markets. Two distinct marketing opportunities exist for chip potatoes in the eastern region. Potato producers from the more southern areas sell their potatoes for processing directly following harvest. The varietal requirements for these regions stress earliness, chip quality from the field, and tolerance to high temperature at bulking time. The Atlantic variety currently predominates in these areas; however, it is very susceptible to internal heat necrosis (IHN), a serious quality defect (Henninger et al., 1979). IHN is a very serious defect throughout many of the eastern-coastal and southeastern states. These regions need new varieties that are free of IHN and produce high quality chips within seven days of harvest, while still maintaining the high yields and high specific gravity of Atlantic.
Processing growers from the northern states sell most of their crop following storage. These growers need high yielding, high specific gravity varieties with the ability to process into chips or fries from long-term, cold storage. Most of the russeted, french fry varieties developed in the western and mid-western states are poorly adapted to the East, as is the standard variety, Russet Burbank. A major goal is to develop russet varieties with high yield, improved disease resistance, uniform long tuber shape, high specific gravity and acceptable fry color under eastern growing conditions. This is critical for Maine's expanding french fry markets and could allow expansion of french fry processing into other eastern states.
Disease- and Insect-Resistant Cultivars are Needed. Commercially produced potatoes, Solanum tuberosum spp. tuberosum, in North America lack sufficient resistance to important pests. Foliar fungicide applications for control of late blight (Phytophthora infestans) and early blight (Alternaria solani) represent approximately 80% of the pesticide active ingredient applied to eastern potatoes during a typical growing season. These applications are costly to growers and may result in chronic environmental degradation and/or health problems for agricultural workers. Genetic resistance to major pests is critical to ensuring efficient crop production and improving protection of the environment. Disease and insect resistant cultivars provide an economical and environmentally sound alternative to pesticide use on potatoes. Concerted efforts are needed to identify new genetic sources of resistance and incorporate them into productive S. tuberosum clones. In addition to late blight, early blight, white mold (Sclerotinia sclerotiorum) and verticillium wilt (Verticillium dahliae and V. albo-atrum), which are visibly present in foliage and destroy the crop or reduce yield and quality, numerous other pests and diseases hamper potato production in the region. Colorado potato beetle (CPB, Leptinotarsa decemlineata), aphids (e.g. Myzus persicae and Macrosiphum euphorbae), and leaf hoppers (Empoasca fabae) are commonly encountered insect pests in the eastern United States. Cosmetic diseases of the potato tuber such as scab (Streptomyces spp.), silver scurf (Helminthosporium solani), black scurf (Rhizoctonia solani), and powdery scab (Spongospora subterranea), can result in a crop that is unmarketable for seed or table use. Wart ( Synchytrium endobioticum Schilb.) and golden nematode (Globodera rostochiensis) are so destructive to the potato crop that their spread is controlled by quarantine regulations which have limited their occurrence in North America to a few distinct production areas. Other nematodes (e.g. Pratylenchus spp.) are widespread and are controlled by chemical fumigation and crop rotation. Virus diseases (e.g. potato viruses A, M, S, X, Y; potato leafroll virus, potato spindle tuber viroid, tobacco rattle virus) that impact potato productivity and quality are controlled by eliminating insect vectors that spread several of the diseases, sanitation, and careful propagation of virus-free seed. Similarly, bacterial ring rot (Clavibacter michiganense subsp. sepedonicus) is a destructive potato pest that is controlled by sanitation, careful inspection, and strict seed production regulations. Once the crop is in storage, storage decay caused by a range of pathogenic organisms (e.g. Erwinia carotovora, Phytophthora erythroseptica, Pythium spp, Fusarium spp., P. infestans, and A. solani) can cause complete and devastating losses to growers.
Current CPB and aphid control strategies rely heavily on the use of insecticides; however, CPB rapidly develops resistance to most insecticides soon after their commercial introduction. Likewise, P. infestans, P. erythroseptica, Helminthosporium solani and Fusarium species have developed resistance to fungicides previously used for control. The region's potato breeding programs are actively targeting their crossing and selection efforts to improve resistance to the most economically important diseases and insect pests of potatoes. In addition, it is necessary to screen germplasm for diseases which may occur locally or sporadically across locations (e.g. pink rot, rhizoctonia, white mold, powdery scab, etc.). Information on the disease reaction of a new cultivar is important because it reduces the risk of severe loss to sporadic disease, reduces inputs required for disease control, and allows growers to avoid particularly susceptible cultivars in areas at particular risk. Where the primary control of disease is by inspection rather than resistance (such as viruses and bacterial ring rot), selection can prevent the release of tolerant cultivars which harbor inoculum without showing detectable symptoms. Development of pest-resistant potato cultivars will be an essential resource for commercial potato growers.
Early-Maturing Cultivars. Well-adapted potato cultivars that require fewer days to produce high marketable yields would be specifically advantageous in much of the East. Unlike most western production areas, short seasons (e.g., approximately 90-110 days) prevail in much of the East, especially in northern areas, placing many growers at a possible competitive disadvantage. The development of early-maturing cultivars would also be advantageous in southeastern locations because these cultivars would escape excessively high summer temperatures that decrease yield and tuber quality. Potato production in Florida would benefit, specifically, from the development of short-day varieties that match Florida's production window. Early-maturing cultivars would also be useful in intensively-managed systems (e.g., organic, hoop houses, etc.), especially if access to the earliest markets and/or escape from persistent weed, disease, and insect pressure were desired. Cultivars requiring fewer days to mature may also require fewer applications of chemical vine killers, fertilizers, or crop protectants, thereby reducing input costs and potential negative environmental impacts.
Coordinated Eastern Approach to Potato Breeding, Selection, and Variety Development. Potatoes grown in the East are exposed to a wide range of day length, day and/or night temperatures, soils, humidity, and moisture conditions. These diverse environmental conditions can have dramatic effects on the performance and acceptability of potato breeding lines (Tai, et al., 1994). Genotype by environment interactions must be evaluated to aid in breeding for new cultivars with improved adaptation to production sites and cultural practices (Hill, 1975; Souza et al., 1993; Zobel et al., 1988). Thus, the development of a new cultivar is not complete until it has been properly evaluated over a range of environmental conditions, a wide array of disease and pest pressures, and subjected to numerous production practices. The regional research approach used in the NE-184 project is an efficient method of generating information on genotype by environment interactions. It provides information needed for rational selection of widely adapted varieties and also helps identify varieties that are suited to only a limited growing area. This information is essential for breeders, researchers, extension agents, growers, and the entire eastern potato industry.
It may take 10-15 years from the time a cross is made until a new cultivar is released. Breeders generate new germplasm with their crosses and then distribute seed to a limited number of cooperating scientists, obtain information from these scientists, and make final decisions as to which selections have enough merit to put into tissue culture and enter into certification programs. Before a selection is entered into certification programs for regional testing in the NE-184 project, breeders have been working closely with pathologists, entomologists, physiologists, and agronomists. Such cooperation frequently involves several institutions in the region. Evaluations for specific traits are conducted at those institutions where the expertise exists, not necessarily at those institutions where the breeding was done. One of the strengths of the NE-184 Project has been the size of the breeding programs associated with it. These breeding programs are large enough to sustain critical mass of germplasm for breeding purposes. Over the years, the breeders associated with these programs have developed a system of cooperation encompassing scientists at multiple state locations to evaluate the developing germplasm for numerous traits that are important to the regional industry. Each state cooperates in this regional testing in the area of their scientific expertise. Such a system minimizes duplication of efforts and maximizes the results for the overall region.
Initial crossing, germplasm improvement, and selection are traditionally conducted within the region's potato breeding programs; however, the diverse environments provided by regional cooperators are increasingly being used to supplement the early-selection process and improve the adaptation of plant materials to specific portions of the East. Once superior progeny are identified, they must be evaluated for additional traits under a wider range of environmental conditions. To accomplish this, the lines are entered into the eastern regional potato variety trials (NE-184 Regional Project) to use the diverse NE-184 environmental conditions to learn more about the geographical adaptation, pest resistance, strengths and weaknesses of the lines. The most promising lines are entered into commercial-scale demonstration trials to begin the final assessment for commercial potential. The NE-184 project is an essential part of this process. It is a collaborative effort of the region's four breeding programs and other researchers in eight eastern states (FL, ME, NC, NJ, NY, OH, PA, and VA).
Stakeholder Input and Potato Variety Development. This project helps facilitate information exchange with growers and coordination of commercial tests. Innovative growers involved in variety development regularly communicate with their peers, markets, and seed distributors. Interaction with these growers provides researchers with an opportunity to obtain input regarding industry's varietal needs and commercial performance of new breeding lines and varieties. Cultural practice, maturity, bruising, yield, quality, and storability information from the commercial trials is used to develop variety management profiles to facilitate subsequent commercial adoption.
Stakeholders play a key role in potato breeding, evaluation, and variety development. Variety adoption is impossible without active interaction between researchers, extension, and industry. All eastern potato breeding programs utilize direct input from growers, processors, and industry groups (e.g. National Potato Council executive board, grower associations, processors, and individual growers, etc.) to provide input on needs and establish priority areas for their breeding efforts. The breeding efforts described in this project proposal (e.g. disease resistance, quality attributes, yield, etc.) are a direct result of this input process. Virtually all NE-184 cooperators maintain close contact with grower groups, processors, potato brokers, and individual growers in their respective states. Needs are relayed through these state contacts and provide a basis for breeding, selection, and evaluation. Growers in each state are introduced to new breeding lines through varied mechanisms (e.g. presentations at winter meetings, research reports, printed articles, field days, research station and on-farm demonstration trials, etc.). Growers share their perceptions on the strengths, weaknesses, and optimum production practices for new varieties. The final decision for naming and release of a new variety is typically based largely on grower or industry input.
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