Duration: 10/01/2007 to 09/30/2012

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Importance of work - Consumer demographics and food preferences present new challenges for farmers who seek to supply high quality, highly nutritional products to consumers, while maintaining economically and environmentally sustainable production practices. This multidisciplinary regional research project helps farmers address these needs. Specifically, we propose to provide farmers new potato varieties to solve production problems and meet consumers changing needs. These varieties will have improved yields, enhanced fresh market, processing or value-added traits, and better pest resistance resulting in reduced chemical inputs. As evidenced in Appendix 1, we have a solid track record in producing new potato varieties that have been commercially accepted. For example, the varieties Reba, Keuka Gold, Pike, Andover, Harley Blackwell and Marcy have all enjoyed success in the marketplace. While King Hairy, a clone resistant to several insects is becoming increasingly popular with organic growers. We propose to continue our regional collaborative efforts to breed, select, and develop improved potato varieties to enhance marketing opportunities and reduce farm dependence on costly agricultural chemicals (e.g. fertilizers, insecticides, nematicides, fungicides, herbicides, vine desiccants, sprout inhibitors, and disinfection agents). Success in our research efforts will benefit growers and the public because it will result in reduced chemical usage and provide new potato varieties with expanded marketing opportunities. This will lead to a more economically and environmentally sustainable potato production system.


Importance of potato production to the Eastern US - Potato ranks amongst the top three vegetable crops produced in FL, ME, NC, NY, OH, PA and VA (USDA NASS 2006). Potato is also a significant portion of the diversified vegetable industries in many other Eastern states. Cash farm receipts for Eastern potatoes during 2005 were approximately $570 million (USDA NASS, 2006). Multiplier effects in the state and regional economies are many times this amount. For example, the Maine potato industrys total impact on the ME economy is estimated at $540 million sales, $230 million income, and 6,100 jobs (Planning Decisions, Inc, 2003). Potato production in the Eastern US 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. Markets range from high value, direct sales of specialty varieties to contracting with large, international processing companies. This span of conditions creates a tremendous diversity in variety needs. Due in part to the large population base in the East, fresh market production remains a significant aspect of the potato industry of most Eastern states (e.g. 20% of MEs and 60% of PAs 2006 crop); however, many potato chip plants are located in the Eastern or Southeastern US, accounting for 42 percent of all chips produced nationwide (USDA, NASS, 2006). Processing for French fries and chips accounted for 67% of MEs utilization during 2006. Also, ME and NY maintain large, high quality seed potato industries which service most of the Easts seed potato markets. Thus, research aiding the Eastern potato industry impacts markets associated with over half of the US population. Consumers benefit from the release of new potato varieties that provide new, high quality products, facilitate efficient production for fresh market, chipping, and other processing markets in the East, and provide improved pest resistance resulting in less pesticide use.


Needs as indicated by stakeholders - Grower and industry stakeholders need high quality improved varieties for the fresh and processing market segments. Stakeholders want new varieties suited to the demanding quality needs of each market segment. New varieties are needed which are also resistant to diseases and insects. In this long-term project, stakeholders have always had a key role in our potato breeding, evaluation, and variety development efforts. Variety adoption is impossible without active interaction between researchers, extension, growers, and industry. All Eastern potato breeding programs utilize direct input from growers, processors, and industry groups (e.g. National Potato Council executive board, state grower associations, processors, and individual growers, etc.) to provide input on needs and establish priorities 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.


New red-skinned varieties, in particular, are in high demand. A premium-priced market exists for red-skinned and novelty varieties. For reds, the skin color needs to be 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. The organic sector is also a very rapidly increasing production and marketing segment that would benefit greatly from varieties developed by this project. New varieties containing multiple resistances to insects, pathogens and stress factors would provide better performance without chemical inputs in this growing market segment.


For the processing types, two distinct marketing opportunities exist for chip potatoes in the Eastern region. Potato producers from the southern areas (FL, NC, VA, NJ, OH) sell their potatoes for processing directly following harvest. The variety requirements for these regions stress earliness, chip quality from the field, and tolerance to high temperatures during bulking. Atlantic currently predominates in these areas; however, it is very susceptible to internal heat necrosis (IHN), a serious quality defect throughout many of the Eastern-coastal and Southeastern states (Henninger et al., 1979; Yencho et al., 2007). 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.


Contrasted with the south, processing growers from the northern states (PA, NY, and ME) sell most of their crop following storage. These growers need high yielding, high specific gravity varieties with low defect levels and the ability to process into chips or fries from long-term cold storage. Most of the russet- and French fry-type 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, low internal and external defects, and acceptable fry color under Eastern growing conditions. This is critical for Maines French fry markets and could allow expansion of French fry processing into other Eastern states.


In all market sectors, disease- and insect-resistant varieties are also needed for the Eastern potato production system. Commercially produced potato, Solanum tuberosum spp. tuberosum, in North America lacks sufficient resistance to many important pests. While significant progress has been made addressing these needs, much work remains. Foliar fungicide applications for control of late blight (Phytophthora infestans) and early blight (Alternaria solani) account for 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. Disease and insect resistant varieties provide an economical and environmentally sound alternative to pesticide use.


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. 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 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.


Advantages of a collaborative, multistate research project - This project addresses the needs of the Eastern potato industry through a collaborative process of potato breeding, selection, evaluation, and variety release (see Appendix 2 for a flow chart of this system). This project is a highly collaborative project involving eight states and four breeding programs in the Eastern US. Our project encourages pooling of regional resources and promotes collaboration and communication among researchers and stakeholders  all with the aim of enhancing farmers ability to provide a safe and nutritious supply of potatoes to consumers in an environmentally sustainable manner that enhances profits and rural America. Our overall goal is to develop an array of attractive, high yielding, disease- and insect-resistant, tablestock, processing and/or specialty-type potato varieties that can be produced by potato farmers in the Eastern US for a diverse consumer base. Within this context, it is important to recognize that the Eastern US region is not only linked geographically, but it is also is closely linked through potato seed sales and product marketing. Thus, regional communication among scientists, farmers and industry members is a critical aspect of the variety development process.


Potatoes grown in the East are exposed to a wide range of day length, day and/or night temperatures, soils, humidity, and moisture conditions. Environmental conditions have dramatic effects on the performance and acceptability of potato breeding lines and varieties (Tai et al., 1993). Genotype by environment interactions must be evaluated to select new varieties with improved adaptation to production sites and cultural practices (Hill, 1975; Souza et al., 1993; Zobel et al., 1988). In addition to breeding, this project conducts collaborative selection and performance trials under diverse environmental conditions and a wide array of disease and pest pressures so that new potato varieties can be selected that are adapted to varying conditions of the Eastern region.

Related, Current and Previous Work

The NE-1014 Project and its predecessors have played a central role in Eastern potato variety development for many years. Appendix 1 provides a table of potato varieties released through this program during 1997-2007. Currently, the NE-1014 project provides a collaborative research program involving eight states, three Canadian Provinces, and two federal agencies (two USDA-ARS laboratories and the AAFC laboratory in Fredericton, NB, Canada). The regional potato variety development projects have allowed potato breeders to share breeding materials and test results. The NE-1014 project has developed a uniform potato germplasm evaluation and selection system, which takes advantage of the diverse environmental and pest incidence conditions of the Eastern region. A uniform seed source is utilized and evaluation methods are standardized across the trial network. The project also provides a mechanism for screening regional selections for specific characteristics at a single location (e.g. early blight, late blight, and powdery scab resistance in PA; golden nematode resistance in NY; bacterial ring rot symptom expression in ME) and multiple locations (e.g. IHN in NC, NJ and VA). This collaborative evaluation system makes efficient use of scientific expertise available in the region, and results in more efficient release and adoption of new potato varieties than would occur without the project. We also recently established a user-friendly web-based variety database that has become a model for the rest of the U.S. potato variety development programs (http://potatoes.ncsu.edu/NE.html).


The objectives and activities of related projects, such as NRSP-6 (introduction, preservation, distribution, and evaluation of Solanum species), NCR-84 (potato genetics), and WRCC-27 (potato variety development) are complementary to this project. NE-1014 interacts with these projects through exchange of promising germplasm, seedling tubers for selection under conditions not available to individual breeding program, and published results. There is a need for good communication between regions to take advantage of widely-adapted germplasm. Occasionally a selection from the Western or North Central region will perform well in the East; however, this is quite unusual. In order to obtain selections that are well adapted to the Eastern U.S., clones usually must be selected in the East.


The incorporation of disease resistance into varieties with desirable horticultural characteristics is of immense importance. In New York, golden nematode control would be impossible without resistant varieties. The number of fungicide applications normally used to control late blight on susceptible varieties can be substantially reduced when resistant varieties are grown. In the absence of resistant varieties, common scab, pink rot, and other tuber diseases can severely reduce marketable yield. The breeders in the NE-1014 Project have succeeded in incorporating these and other important resistance factors into many of the recently released varieties and clones now being tested. All selections in the NE-1014 Project are now being screened for the development of internal necrosis, bacterial ring rot symptom expression, and total glycoalkaloid content to insure that these undesirable attributes are not discovered after naming and release of a new variety. Regional screening for pink rot resistance will be added in 2008. Breeding, selection and evaluation of disease- and pest-resistant clones continues to be a priority for NE-1014.


Although progress has been made in developing and introducing new varieties with combined disease resistance, favorable horticultural traits and desirable processing qualities, large-scale commercial adoption is hampered by marketing and seed production constraints. Our project intends to continue its focus on enhancing disease/pest resistance of potato while continuing to meet the diverse marketing needs of the Eastern fresh market (e.g. whites, reds, russets, organic and specialty varieties, etc) and processing (French fries and chipping from field and/or storage) industries. We are also developing additional information and programs to enhance commercialization of new varieties (e.g web-based information, variety profiles, licensing procedures, etc).


Fresh Market and Specialty Varieties. Excellent appearance and cooking quality are essential for fresh market varieties. White- and russet-skinned varieties must have a bright, clean appearance when washed as well as uniform tuber size and shape. Resistance to common scab and other diseases which cause external blemishes is extremely important. Resistance to mechanical damage during handling is critical. Unique tuber skin color (e.g. red, purple, yellow, etc) can enhance appeal and marketing opportunities. Heavy tuber netting and susceptibility to tuber skinning limits the marketability of many white-, purple- and red-skinned varieties in the East, so elimination of these traits is important in our breeding and selection efforts. Yellow-fleshed potatoes are becoming increasingly popular in U.S. markets. Methods for breeding for improved yellow-flesh characteristics have been developed (Haynes et al., 1994; Haynes et al., 1996). Yellow-flesh intensity is highly heritable in the diploid hybrid phu-stn population, indicating that the development of intense yellow-flesh in this population will be relatively easy (Haynes, 2000). Cooking and internal quality are also critical for fresh market. Our project provides an excellent, collaborative system for selecting varieties with good external appearance and resistance to the most common internal defects (e.g. hollow heart, blackspot bruise, and internal heat necrosis). Flavor and sensory components of cooked potato can be compared with various analytical methods (e.g. Oruna-Concha et al., 2001; Jensen et al., 1999; Ulrich, et al., 2000; Vainionopaa et al., 2000); however, these methods have not effectively substituted for sensory evaluation. Our project routinely conducts sensory evaluation of advanced potato selections to assure that new releases meet the markets rigorous quality demands. Potatoes are naturally nutritious and rich in vitamin C; however, introgression of yellow-fleshed diploid phu-stn hybrids into S. tubersosum will increase tuber concentrations of carotenoids, and other phytonutrients that would be highly beneficial to human health. Improving the nutritional quality of potato is a long-term goal of the project. Over the past 10 years, nine fresh market and specialty varieties have been released by this project (Appendix 1). Continued improvement is needed in the quality and pest resistance of potato varieties available to Eastern growers so that marketing opportunities can be expanded and production can be more profitable, while minimizing negative environment impacts.


Chipping and French Fry Processing. Selection of clones that maintain processing quality during cool temperature storage is a high priority of the project and is a viable approach towards reducing sprout inhibitor and energy use. Diploid potato species which have long-term cold storage chipping ability [S. phureja and S. raphanifolium (Hanneman, 1993)] and other germplasm with resistance to sugar accumulation in cold storage are being used to improve the genetic base of chipping potatoes adapted to Eastern conditions. Adapted French fry processing clones are being selected from crosses conducted in ME and other states. New chipping varieties with high yields, high tuber dry matter, reduced susceptibility to bruising, and resistance to IHN are being developed by all Eastern breeding programs. Our research has shown that there is no significant correlation between susceptibility to IHN and either total yield or specific gravity (Henninger et al., 2000) and that diploid hybrid population of S. phureja x S. stenotomum (phu-stn) can be used to expand the genetic base for chipping potatoes and reduce IHN problems for growers. (Haynes et al., 1995; Sterrett et al., 2002). Over the past 10 years, seven chipping and/or French fry processing varieties have been released by this project (Appendix 1). The varieties Pike, Andover, Harley Blackwell and Marcy have been particularly successful in the processing marketplace. However, continued improvements in the yield, quality, and pest resistance of new chipping and processing varieties available to Eastern potato growers are needed.


Potato Diseases Constraining Eastern Production. Bacterial and fungal diseases such as late blight, early blight, scab (common, acid, and powdery), verticillium wilt, rhizoctonia (stem canker and black scurf), silver scurf, pink rot, soft rot, dry rot (Fusarium spp.) and virus diseases (leafroll, potato viruses X and Y, corky ring spot) reduce the yield and quality of the Eastern potato crop. All currently available potato varieties are susceptible to one or more of these diseases. Resistance to fungicides previously used for disease control [e.g. mefenoxam resistance to pink rot (Fitzpatrtick and Lambert, 2006); changes in late blight populations and resistance levels since 1990] makes development of improved genetic resistance particularly important. Breeding and selection for improved disease resistance is a major focal area for the Eastern potato breeding programs and NE-1014. The impacts provided by successful development of high yielding, high quality and pest-resistant potato varieties are tremendous for Eastern growers (e.g,. reduced costs, fewer losses, lower risk, etc.) and the public (e.g. less pesticide use, higher quality, etc.).


Insect Pests and Variety Resistance. Colorado potato beetle (CPB) continues to be the most serious insect threat to Eastern potato production because of the severe damage that it causes and because this insect has developed resistance to all insecticides deployed against it (Weber and Ferro 1994). Aphids, leafhoppers, fleabeetles, and other insect pests also cause significant losses to the profitability of Eastern potato production. Research to develop potatoes resistant to CPB and other insects will contribute to the development of more sustainable approaches to insect control. Resistance to insect pests in the East is focused on the incorporation of two complementary sources of resistance, trichome-mediated resistance from S. berthaultii (Bonierbale et al., 1992, 1994) and leptine-based resistance from S. chacoense (Sanford et al., 1997; Yencho et al., 2000). Considerable progress has been made in the NY program to incorporate glandular trichomes [e.g. NY released NYL235-4 an insect resistant clone for use in germplasm improvement (Plaisted et al., 1992) and has released two insect resistant varieties for organic production]. Leptines are foliage-specific glycoalkaloids that provide potent resistance against CPB. Leptines are coded by only a few genes (Sinden et al., 1986) and are under relatively simple genetic control (Yencho et al., 2000). It is our intent to eventually combine trichome-mediated and leptine-based resistance to provide even more effective and durable insect control.


Regional Evaluation and Modeling Efforts. Performance data obtained from collaborative trials in the NE-1014 project have provided a rich information source to carry out research on genotype x environment interactions in the East. The project has developed two sets of baseline data: one consisting of five industry standards that are grown at all sites; the other being "breeders choices" where each of the participating breeders indicates one to three advanced selections that are tested at all sites for that year. The analytical results provide considerable information on the interplay between genotype and environment. Tai et al. (1993) showed that linear regression was useful for evaluating the performance and adaptability of selections over a range of environments. AMMI (additive main effect and multiplicative interaction model)[Gauch, 1992]; BLUP (best linear unbiased predictor); and REML (residual maximum likelihood)[Genstat, 1993; Horgan, 1992] have been used to further analyze NE1014 trial data with the goal of better understanding genotype x environment interactions and helping us develop better selection tools for potato variety development in the region.

Objectives

1. Conduct multidisciplinary conventional and molecular marker-assisted breeding, germplasm enhancement, and early-generation selection research to improve potato productivity and quality for important Eastern U.S. markets.
   
2. Use novel and improved potato germplasm to reduce the impact of economically important potato pests in the Eastern US.
   
3. Evaluate yield, quality, and pest resistance of preliminary and advanced potato breeding lines in experimental- and commercial-scale trials at multiple Eastern locations to aid industry adoption of new varieties.
   
4. Provide timely and relevant information to stake-holders through various means including the development of a project website and a web-based potato variety performance database for use by researchers, extension, potato growers, and allied industry members.
   

Methods

Objective 1: Conduct multidisciplinary conventional and molecular marker-assisted breeding, germplasm enhancement, and early-generation selection research to improve potato productivity and quality for important Eastern US markets. 1a. Development of a Collaborative Approach to Potato Breeding, Selection, and Variety Development in the Eastern US. Initial crossing and germplasm improvement will be conducted within the ME, NY, NC, VA and USDA-ARS potato breeding programs using the approach outlined in Appendix 2. Most of the crosses conducted within each program utilize parental material that includes S. tuberosum lines from North America, Europe, and the International Potato Center (CIP) in Peru. Parents are selected for desirable yield, quality, and pest resistance traits, as well as pollen and flower fertility. Wild or cultivated diploid germplasm (e.g. S. phureja and S. stenotomum in the USDA-ARS program; S. chacoense for insect resistance in the USDA-ARS and NC programs; and S. berthaultii for insect resistance in the NY program) is also used to introduce novel traits for pest resistance or improved quality. VA will assist in breeding efforts by developing self-pollinating, true breeding inbred lines of diploid potato that can be used in genetic studies. Initial selection is usually done by each breeding program at their field sites. 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 across Eastern environments. Lines will be field tested within each breeding program for 5 to 8 years to evaluate yield, quality (size distribution, external appearance, tuber glycoalkaloid levels, processing quality, etc.), disease resistance (e.g. scab, late blight, early blight, verticillium wilt, etc.), and other characteristics (e.g. tuber greening, bruise susceptibility, vine maturity, cooking quality, etc.). The most promising clones will be entered into the Eastern regional potato variety trials (NE-1014 Regional Project) to use the diverse NE-1014 environmental conditions for further screening and selection. 1b. Quantitative, molecular genetic and biochemical studies to improve processing quality and resistance to internal heat necrosis. Improved Specific Gravity - Extraction of monoploids is expected to result in the deletion of deleterious genes. Doubled monoploids (homozygotes), and dihaploids resulting from anther culture of somatic hybrids resulting from the monoploid fusion (heterozygotes consisting exclusively of alleles that have passed through the monoploid sieve) have been crossed with three high specific gravity diploids from the S. phureja-S. stenotomum population. The specific gravity in these three diploids was significantly higher than Atlantic (Atlantic=1.082; BD278-2=1.101; BD282-2=1.092; BD292-2=1.090). Segregating progeny from these crosses (homoygotes x diploid; dihaploids x diploid) and open-pollinated diploids will be evaluated for plant vigor, plant maturity, flowering, fruit set, pollen fertility, yield, number of tubers, specific gravity, tuber shape, eye depth, and external defects. Family means and variances for these traits will be compared. It is unknown to what extent deleterious genes may be limiting genetic gain in breeding populations. Resistance To IHN - Germplasm from the four breeding programs will continue to be screened for IHN resistance in FL, NC, NJ and VA. The methods used in these studies have been outlined by Henninger et. al. (2000), Sterrett et al. (2003), and Sterrett and Henninger (1997). We have identified IHN-resistant or IHN-susceptible clones that are stable across environments and we have used these to identify putative molecular markers associated with IHN. However, our markers do not explain enough of the IHN trait variance to be used as a selectable marker (McCord, 2005). To further our research, we propose to develop a medium density molecular genetic map for a population of cultivated tetraploid potato using Amplified Fragment Length Polymorphism (AFLP) and simple sequence repeats (SSR) markers. This population is segregating for IHN as well as other important traits such as specific gravity and yield. We will use two marker types for the development of the linkage maps. Large numbers of SSRs have been identified in potato and its close relative, tomato. Feingold et al. (2005) have identified and mapped a number of potato EST-derived SSRs, and Frary et al. (2005) have identified a set of SSR and other PCR-based markers that are mapped in tomato. We intend to use a subset (50-100) of these markers to anchor the maps. Mapping software will be used to identify quantitative trait loci (QTL) for IHN resistance and/or susceptibility, specific gravity, and yield in these studies. We hope to use this information to gain a better understanding of the genetic basis of IHN and develop better markers for this trait. 1c. Further develop and capitalize on the improved genetic base for long-term cold storage processing ability. Tetraploid lines with the ability to chip directly from long-term cold storage at 4F have recently been developed by R. Hanneman of the USDA in Madison, WI and C. Thill of the Univ. of MN. This cold-processing ability results primarily from crosses with the wild species S. raphanifolium. Crosses among lines that chip directly from long-term cold storage and S. tuberosum will be made and evaluated for adaptation in NY and ME. Those with the best agronomic performance will then be crossed with regionally adapted chipping varieties. Progeny from these crosses will be selected based on their ability to produce light colored chips or fries after prolonged cold storage. Promising selections will be entered into regional trials for further evaluation. 1d. Improve the genetic base of specialty potatoes, such as yellow-fleshed and red-skinned types. Yellow-Fleshed Potatoes - Total carotenoid content of yellow-fleshed diploid PHU-STN clones ranged from 3 to 13 times of that found in the yellow-fleshed variety Yukon Gold (Lu et al., 2001). Three diploid yellow-fleshed clones (with 14x, 6-8x, and 2x the carotenoid content of Yukon Gold) have been crossed to a light yellow-fleshed tetraploid selection from TBR. Sixty to 70 offspring have been produced from each of these three crosses. The inheritance of carotenoid content in this segregating population will be evaluated (USDA). Selected clones will be analyzed for processing and/or fresh market capabilities and genotypic stability at multiple state locations to ensure wide adaptability prior to release as a new variety. Red-, Purple-Skinned, and Other High-Value Novel-Colored Potatoes - Crosses and backcrosses will be made between tetraploid TBR and diploid PHU-STN lines with solid or patterned red or purple skin to increase color variation in regionally adapted clones. PHU-STN possesses several interesting color traits including a "double layer" of colored skin that may mask cosmetic damage due to superficial skinning during harvest. Segregating progeny will be evaluated for skin color intensity, tuber conformation and appearance, and resistance to silver scurf (USDA, NY). Red and purple skinned clones will also be intercrossed with yellow-flesh clones to develop a population of colored-skin, yellow-flesh lines (USDA, NY, NC). Objective 2: Use novel and improved potato germplasm to reduce the impact of economically important potato pests in the Eastern US 2a. Improve potato resistance to significant pests in the East. Late Blight - A diploid PHU-STN late blight resistant population has been developed by USDA and PSU. After one cycle of recurrent maternal half-sib selection late blight has been reduced by 1/6th, and another similar reduction in late blight severity is predicted for the next cycle of selection currently underway (USDA, PSU). Late blight resistant clones from both cycles were screened for 2n pollen production, and 4x-2x crosses were made to incorporate late blight resistance from these diploids into the tetraploid population. The resultant 65 clones will be evaluated for late blight resistance beginning in 2008 and additional 4x-2x crosses will be made with late blight resistant diploids from the second cycle population (USDA, PSU). Multiple tetraploid sources of resistance to late blight have been identified from Indian, South American, Latin American, European, and North American germplasm and utilized in crosses. About 600 late blight resistant clones have been identified from preliminary evaluation of the progeny of these crosses. These clones will be evaluated in multiple locations (USDA, PA, MN, and OR) in 2008 to identify stable late blight resistant clones for developing late blight resistant varieties. Some of these late blight resistant clones chip well from storage, and a few even chip well from prolonged cold storage. Early Blight - Resistance to early blight in a diploid PHU-STN population was found to be highly heritable. A recurrent maternal half-sib selection program was initiated for improving early blight resistance in this population. Based on the high heritability of this trait, early blight resistance is predicted to decrease by about 40% in the second cycle of selection (currently underway). However, QTL for resistance to early blight have been identified in the diploid PHU-STN population and one of these QTL was found in an area associated with late maturity. In making selections to constitute the second selection cycle an effort was made to select for earliness, but the cycle two population was noticeably later in maturity than the original population. Selecting for earliness first and then for resistance to early blight may result in a population that is less resistant because one of the major QTL for resistance is associated with late maturity. Other QTL associated with early blight resistance were found to be independent of maturity. We will attempt to develop a marker for late maturity. This will allow us to select earlier-maturing, early blight resistant clones in the future. Scab - To develop molecular markers for resistance to common scab, individuals in a population must be accurately phenotyped. Field trials have been too variable for accurate assessments. To further compound the problem, we have found that the rating scale also affects the results and interpretation of the results. True seed from diploid PHU-STN families with resistance or susceptibility to common scab will be grown in a controlled environment. Known quantities of inoculum will be introduced into sterilized potting mix and seedlings from these diploid families will be grown to maturity in the controlled environment chamber. These same clones will be planted in scab infested field trials at USDA and PA and evaluated for their reaction to common scab. If sufficient segregation is observed in one of these families, molecular markers will be developed. If not, if highly resistant and highly susceptible clones are identified, crosses will be made in all possible combinations to generate families for the molecular marker study. Golden Nematode - Virtually all crosses in the NY breeding program include at least one golden nematode resistant parent. Segregating populations from the breeding program will be evaluated for resistance to both races of the golden nematode and for superior horticultural characteristics. Mapping studies will continue to map the gene(s) conferring resistance to race Ro2 of the golden nematode (NY). Colorado Potato Beetle and Potato Leafhopper - Two complementary approaches will be adopted for this work. The first approach will focus on the introgression of genes for resistance to CPB and PLH from S. berthaultii (Cornell). The second will focus on introgressing genes for leptine biosythesis, a potent class of glycoakaloids from S. chacoense that impart resistance to CPB and are present only in potato foliage (NCSU). Progeny from these crosses will be grown in CPB and/or leafhopper-infested fields each year in NY and NC. The most resistant selections will then be utilized as parents in the next crossing cycle. When the trichome-based and leptine based resistance work has progressed sufficiently we will attempt to pyramid these valuable genes into a common background using traditional and molecular genetic approaches. Combining the two should increase the overall durability of these resistance sources. Pink Rot - Lenape, several of its progeny varieties and Delta Gold (parent of Lenape) will be studied to verify whether Lenape is the source of pink rot resistance in Atlantic, Snowden, Pike and Gem Russet (Fitzpatrick and Lambert, 2006; Salas, et al 2003). Initial studies suggest that resistance is probably conferred by just one or a few major genes from Lenape but by QTL in varieties with intermediate resistance. Selection efficiency for pink rot resistance depends largely on precise understanding of the mode of inheritance of this trait and the number of genetic loci that contributes to the trait. The inheritance of pink rot resistance will be investigated by developing progenies from crosses of resistant clones such as Lenape and Atlantic with susceptible ones. Their progeny and F2/BC generations will be evaluated for pink rot resistance. We will use AFLP markers for initial DNA fingerprinting of the parental genotypes and the resulting polymorphic loci will be used (in subsequent years of the project) for the analysis of co-segregation between the DNA markers and the resistance phenotype. We will also attempt to develop co-dominant PCR-based markers that can eventually be used for routine selection and introgression of resistance loci to elite breeding materials (ME). Objective 3. Evaluate yield, quality, and pest resistance of preliminary and advanced potato breeding lines in experimental- and commercial-scale trials at multiple Eastern locations to aid industry adoption of new varieties. 3a. Evaluate Promising Selections in Standardized Trials for Early Maturity, Quality, and Storage Potential. Seed Increase for Standardized Regional Variety Trials - Advanced selections from the breeding programs will be placed in the NE-1014 Project seed nursery at the University of Maine Aroostook Research Farm in Presque Isle, ME. This nursery will serve as a source of uniform plant material for use by project cooperators. The seed will be tested according to Maine seed certification regulations. This common seed source is a vital component for valid research and modeling of environmental characteristics, since performance of any given clone varies widely according to the growing conditions and storage environments to which the seed stocks are exposed. Regional Variety Trial Procedures - All tablestock, processing and specialty market selections will be evaluated in replicated field trials in multiple locations (FL, ME, NY, NJ, NC, OH, PA, VA) using standardized NE-1014 evaluation techniques and descriptors. These techniques include observations on plant traits to identify selections that mature early with minimal need for chemical desiccation, external tuber appearance, total and marketable yield, tuber size distribution, and internal tuber defects incidence. Bruise susceptibility (Hunter and Reeves, 1983; Pavek et al., 1985), storage weight loss, and sprouting characteristics will also be measured (ME, NY). Each cooperator will be able to evaluate each selection for three growing seasons and then the selection will be removed from NE-1014 seed nursery. Processing from Storage - Samples of varieties and selections entered into the NE-1014 project from the breeding programs will be stored at a minimum of two temperatures. Weight loss will be measured to help select clones that do not require the use of plant growth regulators for sprout suppression. Chip or fry color will be measured with an Agtron instrument or with USDA Chip or Fry Color Charts following storage for two to six months at temperatures ranging from 4 to 10C (ME, NY, PA, USDA). 3b. Evaluate Promising Selections for Resistance to Potato Pests. Early, Late Blight, Scab and Rhizoctonia - All selections undergoing evaluation for possible release as a new variety will be evaluated for their reaction to late blight, scab, rhizoctonia, viruses, ring rot, and pink rot in replicated field trials. Varieties with known reaction to each pathogen will be included each year of the test as a basis for comparison. Early and late blight trials will be conducted in PA and ME. Scab tests (primarily common scab) in PA. Rhizoctonia tests will focus on tuber malformations, presence of aerial tubers, yield losses, and distribution of tubers in the various size categories to determine response to infection in the field and will be conducted by our collaborators in Quebec and ME. Genetic improvement of potato for resistance to rhizoctonia cannot proceed until sources of resistance to rhizoctonia are found. Viruses - Advanced potato breeding selections in the NE-1014 project will be planted in replicated field trials and mechanically inoculated with potato virus X and Y. Visual symptoms of virus infection will be recorded as well as virus titers using ELISA. Advanced selections will be planted in replicated trials in Florida in stubby root infested soil. Tubers will be evaluated externally and internally for corky ringspot, the visual symptom of tobacco rattle virus infection (FL). Ring Rot - Advanced potato breeding selections will be inoculated with Clavibacter michiganense subsp. sepedonicus and planted in replicated field trials in Maine. Foliar symptoms will be recorded during the growing season. At harvest, tuber symptoms will be recorded. Pink Rot - All NE-1014 clones will be screened for pink rot susceptibility at a single site (ME). A field approach will be used until greenhouse/laboratory methods can be developed that reflect field results. 3c. Evaluate promising selections for sensory and nutritional quality. Six to ten advanced selections will be grown each year in ME. Each line will be evaluated for boiling and baking quality after four months of storage at 7oC. Test lines will be compared to appropriate industry standards (e.g. Superior, Katahdin, or Russet Burbank). Only lines with acceptable total gylcoalkaloid (TGA) content (<20 mg per 100g) will be evaluated for sensory quality (Asano et al., 1996; Baker et al., 1991; Friedman and McDonald, 1997). A consumer panel will evaluate the samples in comparison to the appropriate standard variety. A nine point hedonic scale will be used for each of the baked attributes (cooked color, texture, flavor, and overall acceptability). Similar consumer panels and scales will be used for boiled quality attributes (color, flavor, after cooking darkening, sloughing, and overall acceptability). Chlorogenic acid content (Banjongsiniri (1999)) as well as the rate of browning (Sapers and Miller, 1993) will be evaluated at the time of the sensory evaluations. Correlations between chemical and sensory data will be explored. Sensory quality of promising French fry lines will be evaluated in ME. Tubers from each French fry line will be stored at 10oC for two months and then evaluated versus Russet Burbank as a standard. Fries will then be served to panelists for color, texture, flavor and overall quality evaluation. The total solids content of the raw tubers and the fat content of par- and finished fries will be determined following published methods (True et al., 1983). Advanced potato breeding lines will be assayed for phytonutrient quality and quantity (ME). Information will be shared with the breeding programs. Extracted ascorbic acid will be quantified by the microfluorometric method (AOAC, 2000). Tuber carotenoids (lycopene, lutein, and other provitamin A carotenoids) will be determined by reverse phase HPLC according to Bushway (1986) and Simonne et al. (1993; 1997b; 2001). Antioxidant capacity will be measured following the methods of Cao et al. (1996). Protein (Simonne et al., 1997a), moisture, ash, and total lipid content of the tubers will be analyzed by AOAC methods (AOAC, 2000). Information obtained will be used to direct breeding and selection efforts to improve potato nutritional quality. 3d. Study cultural practices that optimize the performance of new potato clones and develop more sustainable agricultural systems. Optimized cultural practices need to be developed for new potato clones to increase the likelihood of success in commercial production. Some important environmental factors may be mitigated by cultural practices such as irrigation, appropriate fertilization or timely harvest. Cultural practice experiments will be performed with new clones to determine optimal input levels (ME, NY, PA, FL, NC, NJ). These studies may include fertilization, harvest date, irrigation, plant spacing, and other cultural practices. A subset of these sites will conduct cultural studies with a range of genotypes to help develop selection tools for specific cultural practices. For example, several sites will evaluate performance of selected pest-resistant lines under organic or low chemical production systems. 3e. Classify the Eastern region environments for use in variety selection and modeling. Data from the NE-temp1302 project will be analyzed using Residual Maximum Likelihood (REML, Genstat, 1993; Horgan, 1992), Best linear unbiased predictor (BLUP) and AMMI (Additive Main Effects and Multiplicative Interaction effects, Zobel et al., 1988; Gauch, 2006) to provide information on the relative merits of breeding lines, test environments, and genotype x environment (GE) interactions. Research will also be conducted on morpho-physiological traits and environmental variables that are causal factors of the GE interactions. The NE-1014 project will continue to work with our rich dataset and new statistical tools to help describe performance of selections, understand GE interactions, and refine the evaluation and selection process. Objective 4. Provide timely and relevant information to stake-holders through various means including the development of a project website and a web-based potato variety performance database for use by researchers, extension, potato growers, and allied industry members. Project cooperators will present project information to stakeholders through oral presentations, printed media, and websites to inform them of promising selections and new variety releases. A long-term database for NE-1014 trials has been established to facilitate the data analysis and encourage collaboration among NE-1014 participants. Web interfaces to this database will be created to allow access for all project participants. The data management system will be augmented through links to data from published studies and public databases. Web pages will be designed to provide general project information, links to participant web sites, as well as, reports and summaries for the general potato research and production community. Our website will provide up-to-date potato production information and project results and an interactive, searchable potato variety trial database designed to provide easy and rapid access to the results of the trials coordinated through the Eastern potato variety development project.

Measurement of Progress and Results

Outputs

• Potato breeders and allied scientists will design improved regional breeding and selection strategies to more efficiently develop varieties for wide geographic areas.
• The germplasm pool of high specific gravity, disease-resistant, insect-resistant and/or nutritionally enhanced clones available for breeding purposes in the US will be broadened.
• New potato varieties with improved disease and/or insect resistance, resistance to IHN, improved processing or fresh market characteristics, and enhanced nutritional quality will be released.
• Several genetic maps of important potato breeding progenies will be developed enabling the identification of genes and/or QTL associated with resistance to internal heat necrosis and other traits such as yield, specific gravity, and resistance to diseases.
• Communication and interactions among potato scientists located in Eastern US and elsewhere will be maintained and strengthened.
• A project website and a web-based potato variety performance database for use by researchers, Extension, potato growers, and allied industry members will be fully implemented.

Outcomes or Projected Impacts

• New potato varieties with improved disease and insect resistance, resistance to IHN, improved processing or fresh market characteristics, and enhanced nutritional quality will be released, providing growers with better marketing opportunities and/or improved resistance to pests.
• Adoption of new, high quality, pest resistant varieties will be more rapid, leading to increased profitability, greater worker safety, and reduced pesticide load in the environment and human diet.
• Web-based and traditional conduits for the distribution of timely and readily available potato variety production information to growers, allied industry members and consumers will be further developed and strengthened.
• Rural communities dependent upon Eastern potato production will be better stabilized resulting in improved economic and environmental sustainability of Eastern potato industries.

Milestones

(2008): Incorporate disease and insect resistances, abiotic stress resistances, improved processing characteristics, and enhanced nutritional quality, from diverse diploid and tetraploid potato species into high quality, adapted germplasm (S. tuberosum). (on-going activity)

(2008): Quantitative, molecular genetic and biochemical studies to improve processing quality and resistance to internal heat necrosis commenced. (on-going activity)

(2008): Interactive and searchable potato variety trial database designed to provide easy and rapid access to the results of the trials coordinated through the Eastern potato variety development project established. (on-going activity)

(2008): Diploid PHU-STN late blight resistant population developed by USDA and PSU and early blight mapping research commenced.

(2009): Molecular genetic map of potato IHN mapping population developed.

(2009): Crosses and backcrosses made between tetraploid TBR and diploid PHU-STN lines with solid or patterned red or purple skin to increase color variation in regionally adapted clones and selections made. (on-going activity)

(0):10): QTLs associated with resistance to internal heat necrosis, yield, specific gravity, earliness and chipping ability as feasible in IHN mapping population.

(0):10): Late blight resistance of 4x-2x breeding populations identified and transferred into adapted S. tuberosum germplasm, and stable late blight resistant germplasm identified.

(0):010): Crosses among S. raphanifolium lines that chip directly from long-term cold storage and S. tuberosum made and evaluated for adaptation in NY and ME.

(0):11): Inheritance of high carotenoid content in 4x-2x hybrids determined and crossing initiated to introgress traits of interest.

(0):11): Family means and variances for diploid families resulting from doubled monoploid x diploid and dihaploid x diploid hybrids, and open-pollinated diploids compared and breeding initiated to introgress traits of importance.

(0):10): Research to develop molecular markers to expedite the development of scab resistant and/or early maturing, early blight resistant germplasm and varieties commenced.

(0):10): Improved nematode and insect resistant germplasm identified and crosses with advanced S. tuberosum breeding lines to develop varieties with resistance to GN and/or improved resistance to CPB and PLH made. (ongoing activity)

(0):11): Pink rot resistant germplasm developed and molecular mapping efforts commenced.

(0):12): Eastern region environments classified for use in variety selection and modeling.

Projected Participation

View Appendix E: Participation

Outreach Plan

The NE-1014 Regional Potato Variety Development Project currently conducts extensive outreach activities in all participating states using numerous techniques ranging from face-to-face presentations at grower and scientific meetings to providing web-based content for industry members and consumers. Typical outreach activities include:
1. Publication of project results in the NE-1014 annual publication, scientific journals, and other outlets.
2. Development of applied publications and Extension materials targeted to growers in each participating state or province.
3. Multiple formal and informal presentations, demonstrations, and field days targeted to growers and industry in each participating state or province.
4. Providing web-based project information via the NE-1014 project website to enhance access to research results, variety profiles, and photographs (http://potatoes.ncsu.edu/NE.html).

Organization/Governance

The regional technical committee is composed of all participating cooperators (see Section 11, attachments), an administrative advisor (Dr. Kirby Stafford) appointed by the Northeast Agricultural Experiment Station Directors, and a CSREES Representative (Dr. Ann Marie Thro). The technical committee meets at least once each year to discuss progress of the research, review procedures, coordinate research and plan future research activities. Voting privileges are restricted to one member from each participating unit.


The regional technical committee will elect an executive committee composed of a chair, vice-chair, and secretary. A succession of officers will be maintained so that the vice-chair becomes chair, the secretary becomes vice-chair, and a new secretary is elected each year. The responsibilities of the executive committee members are as outlined in the Guidelines for Multistate Research Activities. The chair will preside at all meetings of the technical committee and is responsible for organizing the agenda of the annual meeting. The vice-chair will prepare the annual report for the project. The secretary will prepare the minutes of the annual meeting and any special meetings. The administrative advisor is responsible for distributing the minutes and submitting the annual report and minutes to the CSREES representative and other interested parties. Participation by Agriculture Canada, the Provinces of Quebec and Prince Edward Island, Maine Department of Agriculture, Cooperative Extension, and Industry representatives is at the invitation of the Technical Committee with the approval of the Administrative Advisor.

Literature Cited

AOAC International. 2000. Official Methods of Analysis, 17th ed.

Asano, M., N. Goto, and K. Isshiki. 1996. J. Jpn. Soc. Food Sci. Technol. 43:593-597.

Baker, D.C., R.F. Keeler, and W. Gaffield. 1991. Toxicosis from steroidal alkaloids of Solanum species. In: Handbook of Natural Toxins, Keeler, R.F., Ed., Marcel Dekker, New York, Vol 6., 71-82.

Banjongsinsiri, P. 1999. The influence of potato cultivar and chemical treatment on the development of a pre-peeled, refrigerated product. M.S. Thesis, University of Maine, 104 pp.

Bliss, C.I. 1960. Some statistical aspects of preference and related tests. Appl. Stat. IX (1):8-19.

Bonierbale, M.W., R.L. Plaisted and S. Tanksley. 1992. Genetic mapping and utilization of quantitative trichome-mediated insect resistance in potato. Neth. J. Pl. Path. 98 Supplement 2:211-214.

Bonierbale, M.W., R.L. Plaisted, O. Pineda and S.D. Tanksley. 1994. QTL analysis of trichome-mediated insect resistance in potato. Theor. Appl. Genet. 87:973-987.

Bushway, R.J. 1986. Determination of a- and P-carotene in some raw fruits and vegetables by
high-performance chromatography. J. Agr. Food Chem. 34:409-412.

Cao, G. E. Sofic, and R.L. Prior. 1996. Antioxidant capacity of tea and common vegetables. J. Agr. Food Chem. 44:3426-3431.

Feingold S., J Lloyd, N. Norero, M. Bonierbale, and J. Lorenzen. 2005. Mapping and characterization of new EST-derived microsatellites for potato (Solanum tuberosum L.). Theoretical and Applied Genetics 111:456-466.

Fitzpatrick, E., D.H. Lambert 2006. Phytophthora erythroseptica fungicide options and mefenoxam (metylaxyl) insensitivity among isolates in Maine. Solanaceae / PAA Annual Meeting, Madison, WI 25 July, 2006

Frary A., Y. Xu, J. Liu, S Mitchell, E. Tedeschi, and S. Tanksley. 2005. Development of a set of PCR-based anchor markers encompassing the tomato genome and evaluation of their usefulness for genetics and breeding experiments. Theoretical and Applied Genetics 111:291-312.

Friedman, M., and G.M. McDonald. 1997. Potato glycoalkaloids: Chemistry, analysis, safety and plant physiology. Crit. Rev. Plant Sci. 16:55-132.

Gauch, H.G. Jr. 2006. Statistical Analysis of Yield Trials by AMMI and GGE. Crop Sci. 46:1488-1500.

Genstat 5 release 3 Reference Manual. 1993. Chapter 10: REML estimation of variance components and analysis of unbalanced designs. Pp. 539-584.

Hanneman, R.E., Jr. 1993. Ability of wild and cultivated potato species to chip directly from 2C storage. Am. Potato J. 70:814.

Haynes, K.G. 2000. Inheritance of yellow-flesh intensity in diploid potatoes. J. Amer. Soc. Hort. Sci. 125:63-65.

Haynes, K.G., W.E. Potts, J.L. Chittams and D.L. Fleck. 1994. Determining yellow-flesh intensity in potatoes. J. Am. Soc. Hort. Sci. 119:1057-1059.

Haynes, K.G., J.B. Sieczka, M.R. Henninger and D.L. Flock. 1996. Clone x environment interactions for yellow-flesh intensity in tetraploid potatoes. J Am Soc Hort Sci

Haynes, K.G., D.R. Wilson and M.S. Kang. 1995. Genotype x environment interactions for specific gravity in diploid potatoes. Crop Sci 35:977-981.

Henninger, M. R., J. W. Patterson, and R.E. Webb. 1979. Tuber necrosis in Atlantic. Amer. Potato J. 56:464.

Henninger, M.R., S.B. Sterrett and K.G. Haynes. 2000. Broad-sense heritability and stability of internal heat necrosis and specific gravity in tetraploid potatoes. Crop Science. 40:977-984.

Hill, J. 1975. Genotype-environment interactions -- a challenge for plant breeding. J. Agr. Sci. 85:477-493.

Horgan, G.W. and E.A. Hunter. 1992. Introduction to REML for scientists. 59pp. Univ. of Edinburgh.

Hunter, J.H. and A.F. Reeves. 1983. Respiration increase as an objective measurement of relative susceptibility to bruise damage in breeding clones. Am Potato J 60:811(abst.).

Jensen, K., M.A. Peterson, L. Poll, and P.B. Brockhoff. 1999. Influence of cultivar and growing location on the development of flavor in precooked vacuum-packed potatoes. J. Agric. Food Chem. 47:1145-1149.

Kleinhenz, M.D., D.M. Kelly, E.C. Wittmeyer, B. Schult, D.R. Miskell, J.Y. Elliott, W.D. Bash, and R.J. Keller. 2001a. Report of results from the 2000 Ohio potato germplasm evaluations, the North-central (NCR84) and Northeast (NE184) Regional Projects Cooperating, The OSU Horticulture and Crop Science Series No. 706, Jan. 2001. 53 pp.

Kleinhenz, M.D., E.C. Wittmeyer, Mark A. Bennett, and Richard L. Hassell. 2001b. Variety selection for resistance to abiotic stresses, a summary of Ohios involvement in the North-central and Northeast Regional Genetics and Breeding Projects. Potato Association of America Annual Meetings, 2001. Amer Jour Potato Res. In press.

Lambert, D.H. and B. Salas. 2001. Pink Rot in W.R. Stevenson, R. Loria, G.D. Franc and D.P. Weingartner (eds.) Compendium of Potato Diseases, 2nd ed. American Phytopathological Society Press, St Paul, MN. Pp.33-34.

Love, S.L., B. Shafii, L.C. Haderlie, and C. Eberlein. 1993. Use of foliar symptoms and plant height to predict yield loss in potatoes due to metribuzin injury. Am Potato J 70:517-525.

Lu, W., K. Haynes, E. Wiley, and B. Clevidence. 2001. Carotenoid content and color in diploid potatoes. J. Amer. Soc. Hort Sci. 126:722-726.

McCord, Per Hilding. 2005. Sinks above and sinks below physical mapping of fruit-derived ESTs in peach, a model species for Prunus and Rosaceae structural genomics, and identification of amplified fragment length polymorphism (AFLP) markers associated with internal heat necrosis (IHN) in 4x-2x Solanum tuberosum x S. phureja-S. stenotomum hybrids. MS Thesis, NC State University., 122pp.

National Potato Council. 2005. 2005-2006 Potato statistical yearbook. NPC, Englewood, CO, 96pp.

Oruna-Concha, M.J., S. C. Duckham, and J. M. Ames. 2001. Comparison of volatile compounds isolated from the skin and flesh of four potato cultivars after baking. J. Agric. Food Chem. 49:2414-2421.

Pavek, J., D. Corsini, and F. Nissley. 1985. A rapid method for determining blackspot susceptibility of potato clones. Am Potato J 62:511-517.

Plaisted, R.L., W.M Tingey and J.C. Steffens. 1992. The germplasm release of NYL235-4, a clone with resistance to the Colorado potato beetle. Am. Potato J. 69:843-846.

Planning Decisions, Inc. 2003. A study of the Maine Potato Industry, its economic impact. S. Portland, ME, 36 pp.

Salas, B, G.A. Secor, R.J. Taylor, and N.C. Gudmestad. 2003. Assessment of resistance of tubers of potato cultivars to Phytophthora erythroseptica and Pythium ultimum. Plant Dis. 87:91-97

Sanford, R.S. Kobayashi, K.L. Deahl, and S.L. Sinden. 1997. Diploid and tetraploid Solanum chacoense genotypes that synthesize leptine glycoalkaloids and deter feeding by Colorado potato beetle. Am Pot J 74:15 21.

Sapers, G.M and R.L. Miller. 1993. Control of enzymatic browning in pre-peeled potatoes by surface digestion. J. Food Sci. 58:1076.
Simonne, A.H., S.J. Kays, P.E. Koehler, and R.R. Eitenmiller. 1993. Assessment of beta-carotene content in sweetpotato (Ipomoea batatas Lam.) breeding lines in relation to dietary requirements. J. Food Compos. Anal. 6:336-345.

Simonne, A.H., E.H. Simonne, R.R. Eitenmiller, H.A. Mills and C.P. Cresman, III. 1997a. Could the Dumas method replace the kjeldahl digestion for nitrogen and crude protein determination in foods?. J. Sci. Food Agr.73:39-45.

Simonne, A. H., E. H. Simonne, R.R. Eitenmiller, H.A. Mills, and N.R. Green. 1997b. Ascorbic acid and provitamin A contents of unusual colored bell peppers (Capsicum annuum L.). J. Food Comp. Anal. 10:299-311.

Simonne, A.H., T.-S. Huang, and C.I. Wei. 2001. Cooking time unequally affects carotenoids in different vegetables. Paper presented at the 2001 Annual IFT meeting, NewOrleans, LA.

Sinden, S.L., L.L. Sanford, and K.L. Deahl. 1986. Segregation of leptine glycoalkaloids in Solanum chacoense Bitter. J Agric Food Chem 34:372-377.

Souza, E., J.R. Myers and B.T.Scully. 1993. Genotype by environment interaction in crop improvement. In: Crop Improvement for Sustainable Agriculture. Edited by M.B. Callaway and C.A. Francis. University of Nebraska Press. pp. 192-233.

Sterrett S.B. and M.R. Henninger. 1997. Internal heat necrosis in the mid-Atlantic regioninfluence of environment and cultural management. Am Potato J 74:233-243.

Sterrett, S.B., M.R. Henninger, G.C. Yencho, W. Lu, B.T. Vinyard, and K.G. Haynes. 2003. Stability of internal heat necrosis in tetraploid x diploid potatoes. Crop Science43: 790-796.

Tai, G.C.C., T.R. Tarn, G.A. Porter and S.B. Sterrett. 1993. Performance evaluations of varieties and selections in the Northeastern regions of North America. Amer. Potato J. 70:685-698.

True, R.H., T. M. Work, R. J. Bushway, and A.A. Bushway. 1983. Sensory quality of French fries prepared from BelRus and Russet Burbank potatoes. Am. Potato J. 60:933-937.

Ulrich, D., E. Hoberg, W. Neugebauer, H. Tiemann, and U. Darsow. 2000. Investigation of the boiled potato flavor by human sensory and instrumental methods. Am. J. Potato Res. 77:111-117.

USDA National Agricultural Statistics Service. 2005. Potato Production Statistics.

Vainionopaa, J., R. Kervinen, M. de Pardo, E. Laurila, M. Kari, L. Mustonen, and R. Ahvenainen. 2000. Exploration of storage and process tolerance of different potato cultivars using principal component and canonical correlation analyses. J. Food Eng. 44:47-61.
(1972).

Weber, D.C. and D.N. Ferro. 1994. Colorado potato beetle: diverse life history poses challenge to management. In: G.W. Zehnder, R.K. Jansson, M.L. Powelson, and K.V. Raman (eds.). Advances in Potato Pest Biology and Management. APS Press, St. Paul, MN.

Yencho, G.C., Kowalski, S.P., Kennedy, G.G., and Sanford, L.L. 2000. Inheritance of leptine glycoalkaloids and resistance to Colorado potato beetle (Leptinotarsa decemlineata Say) in F2 Solanum tuberosum (4x) X S. chacoense (4x) potato progenies. Am. J. Potato Res. 77: 167 178.

Yencho, G.C., P.H. McCord, K.G. Haynes, and S.B. Sterrett. 2007. Internal heat necrosis of potato  a review. AJPR. (in press).

Zobel, R.W., M.J. Wright and H.G. Gauch, Jr. 1988. Statistical analysis of a yield trial. Agron. J. 80:388-393.

Attachments

Land Grant Participating States/Institutions

FL, MD, ME, NC, NJ, NY, OH, PA, VA, WI

Non Land Grant Participating States/Institutions

Beltsville Area, Maine Seed Potato Board