Brief Summary of Minutes of Annual Meeting

Summary of Minutes The 35th annual meeting of NCR-84 was held at the Best Western OHare in Rosemont, Illinois, on February 7-8, 2005. Dr. Asunta Thompson chaired the meeting. Dr. Thompson called the meeting to order at 1:00 p.m. by welcoming participants and asking attendants to introduce themselves. A motion was made by Jansky and seconded by Douches to accept the minutes from the 2004 meeting. Gary Lemme (administrative advisor) indicated that the organization can no longer by designated as an NCR group. The group must decide whether it should be designated a Coordinating Committee or an Education/Extension Research Activity. NCR-84 has been approved through September 30, 2007. A renewal application must be submitted during the fall of 2006. A new administrative advisor will be assigned to the group during the fall of 2005. Shelley Jansky announced a position opening at the USDA in Madison for a potato storage physiologist. David Douches, Technical Representative for the NRSP-6 (U.S. Potato Genebank), indicated that discussions are underway regarding the mechanism of funding for the genebank. The North Central region needs to submit a report indicating how NRSP-6 is being utilized by breeders. John Bamberg indicated that, during the period 2006-2010, a 5% budget cut is scheduled for each year. Christian Thill indicated that breeders should be informed of the annual NRSP-6 meeting so they can attend if interested. David Douches indicated that breeders should send him information about utilization of NRSP-6 germplasm so he can include it in the report. The North Central Potato Variety Trial Report was handed out. Twenty-three clones were evaluated from Wisconsin, Minnesota, Michigan, North Dakota, the USDA-Madison, Wisconsin, and Agriculture Canada. The clones were planted in four replicates of 20-hill plots at each site. Reports were presented from individual states (see Abbreviated State Reports of NCR-84 Committee). A motion was made by Christian Thill and seconded by David Douches to consider the group to be a coordinating committee. The motion passed unanimously. David Douches and Christian Thill agreed to be responsible for the renewal application. A motion was made by David Douches and seconded by Christian Thill to elect Jiwan Palta (UW-Madison) to become NCR-84 secretary. The motion passed unanimously. The site for the 2005 NRC-84 annual meeting and date will be chosen by the chair. The officers for 2006 are as follows: Chair  David Spooner, USDA/ARS, University of Wisconsin-Madison Vice-Chair  Shelley Jansky, USDA/ARS, University of Wisconsin-Madison Secretary  Jiwan Palta, University of Wisconsin-Madison Abbreviated State Reports of NCR-84 Committee Dr. Jiwan Palta, Department of Horticulture, University of Wisconsin-Madison The Wisconsin potato breeding program consists of Dr. Jiwan Palta, Dr. Jiming Jiang, and Mr. Bryan Bowen. Dr. Palta described his efforts to develop cultivars with improved calcium accumulation in the tubers. Calcium levels are low in existing cultivars and quality increases as calcium levels increase. Improvements are resulting from exploiting existing variation in cultivars and from utilization of wild Solanum species with high calcium levels. Dr. Jiangs research continues to focus on fighting late blight using the RB gene from Solanum bulbocastanum. Efforts are being made to deploy the gene into cultivars and use marker-assisted selection to identify clones carrying the gene. Mr. Bowen reported on the status of the Wisconsin breeding program. Dr. Palta will be taking over the program as Dr. Jiang phases out of the program by the end of 2006. A replacement for Horia Groza, who retired in 2004, will be hired during the spring of 2005. In 2004, the breeding program planted 70,000 single hills in the field. Approximately 33% of those tubers came from exchanges with other breeders. Two promising selections currently under evaluation include the russet clone W2683-2Rus and the red clone W2799-1R. The Spud Pro program is being used to kick start the commercialization process when superior clones are identified. Dr. Douglas Rouse, Department of Plant Pathology, University of Wisconsin-Madison. Dr. Doug Rouse reported that the organic variety research project is beginning its third year. In 2004, 332 cultivars and breeding clones were planted in three 10-hill replications on two certified organic farms in Wisconsin. Alaska Redeye had the highest marketable yield of approximately 300 cwt. No russets were among the highest-yielding clones. There is some concern about how the varieties obtained for this project will be maintained after the project is terminated. Dr. Benoit Bizimungu, Agriculture and Agri-Food Canada. Dr. Bizimungu has replaced Dr. Dermot Lynch, who has retired. In 2004, PSTV was identified in some tuber materials sent to Canada for the North Central yield trial, so the trial plots were destroyed and no data were obtained. The breeding program mirrors industry in the proportions of effort it puts into different market classes. Seventy percent of the clones it generates are for French fries, 20% for chipping and 10% for fresh market. Dr. Qin Chen, Agriculture and Agri-Food Canada. Dr.Chen is using protoplast fusion of access S. pinnatisectum as a source of late blight and Colorado potato beetle resistance. High levels of resistance have been identified in the hybrids and they are beginning to flower, but they have not been used successfully in crosses yet. Dr. David Fisher, Department of Life Sciences, Maharashi University of Management. Dr. Fisher is using recurrent selection to develop clones with horizontal resistance to Colorado potato beetle. In 2004, many seedlings were destroyed before they could be evaluated, presumably due to small mammal damage. Dr. David Douches, Department of Crop and Soil Sciences, Michigan State University. Dr. David Douches announced that the Michigan and Maine potato breeding programs will soon be jointly releasing a chipping clone named Beacon Chipper. Joe Coombs indicated that a major focus of the Michigan program is late blight resistance. Cultivars and breeding clones are being transformed with the RB gene. Transformants containing the gene range from susceptible to resistant. Efforts are also focusing on developing transgenics without selectable markers. Joe Kuhl is also looking at RB transformants. Some transformed lines have lost the RB gene. Other lines contain the RB gene, but are susceptible. In one line, the gene is not being expressed. In another line, it is expressed so he is working to determine why the line is susceptible. Elizabeth Crowell reported on her work to obtain marker-free transgenic potatoes. A two-vector system is being used  one vector contains the marker gene, the other contains the gene of interest. Transgenics should segregate for the marker gene and the gene of interest, so it should be possible to select progeny with the gene of interest, but not the marker gene. Elizabeth also discussed a project that is being initiated to improve vitamin E levels in potato by increasing levels of the precursor tocopherols. Susannah Cooper is studying the insecticidal activity of avidin against Colorado potato beetle larvae. Avidin functions as an insecticide, but can not be effectively applied as one. Transgenics with the avidin gene reduce the growth rate of larvae in detached leaf assays. Dr. Christian Thill, Department of Horticultural Science, University of Minnesota. Dr. Christian Thill indicated that his breeding program emphasizes early generation selection for biotic and abiotic stress resistance. In his program, he collects all tubers of single hill selections so some tubers can be used for evaluations. Clones are selected for market limiting factors before early generation selection is imposed for other traits. Asymptomatic PVY clones are a major problem in the Minnesota seed certification program. One research project is attempting to determine the genetic basis of the asymptomatic PVY trait. Another research focus is early generation selection for resistance to cold sweetening. Dr.Thills program has determined that a breeder has a better chance of identifying a cold chipper tubers are pre-conditioned at harvest instead being put directly into cold storage. Dr. Thill is initiating a participatory plant breeding project. He lets local organic growers walk the single hill plots after he has finished selection. The growers are allowed to pick up any hills that were left behind. Ioana Dinu discussed her work with triploid and diploid S. verrucosum x S. pinnatisectum hybrids. Trivalents were observed in triploids and up to 12 bivalents were observed in diploids, indicating that recombination occurs between the two genomes. The hybrids exhibit cytoplasmic genetic male sterility. Dr. Susie Thompson, Department of Plant Sciences, North Dakota State University. Dr. Susie Thompson discussed the North Dakota State University potato breeding program. It focuses on resistance to late blight, Colorado potato beetle, green peach aphids, cold sweetening, and sugar ends. In 2004, the program evaluated 79,937 single hills from NDSU and 17,411 from other programs. In 2004, the program released Dakota Jewel. The variety has good skin set, so storage quality is good. Bryce Farnsworth discussed efforts to identify Colorado potato beetle resistance. Resistance has been found in clones containing S. vernei, S. tuberosum gp. Andigena , S. polytrichon, S. etuberosum, and S. chacoense. Efforts to incorporate multiple resistance mechanisms and sources to the pest are underway. Dr. Shelley Jansky, Department of Horticulture, USDA, ARS; University of Wisconsin-Madison. Dr. Shelley Jansky introduced her new germplasm enhancement program. Haploid extraction will be used to study the inheritance of resistance to common scab, early blight, and cold sweetening. Selected haploids will be crossed with resistant diploid wild species to develop adapted clones with high levels of resistance. Another new area of research is evaluation of flavor in cultivated and wild potatoes using sensory evaluations and biochemical assays. Ken Frost recently completed his Masters degree. His project determined that resistance to Verticillium wilt can be transferred from diploids to tetraploids following 4x x 2x crosses. He also evaluated methods for identifying Verticillium wilt resistance in segregating populations. Jin-Joo Bae reported on her work to carry out early generation selection for Verticillium wilt resistance. One field season has been completed and clones have been identified with apparent resistance. A second field season with larger replicated trials will determine whether selection was effective. Dr. John Bamberg, USDA, ARS; NRSP-6 Potato Genebank, Department of Horticulture, University of Wisconsin-Madison. Dr. John Bamberg reported that a collection trip in the Southwest U. S. identified several new populations of S. fendleri. Comparison of these accessions with those already in the gene bank will help to determine whether more collecting should be done. Dr. Bamberg is evaluating tuber acidity in the mini-core collection. Variation has been found among species. The most acidic species are S. polytrichon, S. pinnatisectum, and S. papita, while the least acidic were cultivated clones, S. verrucosum, and S. okadae. The inheritance of the crazy sepal mutant in S. microdontum is being evaluated. This is a floral developmental mutant that results in complete sterility. Additional studies include ecogeographic associations with genetic diversity, disease resistance in S. fendleri and S. jamesii, and the use of fields in Hawaii to generate tubers of wild species.

Accomplishments This research emphasizes the development and evaluation of potato cultivars and germplasm with improved yield, quality, and disease resistance. Regionally, 420,000 new hybrid seedlings were evaluated. Collectively, this is the greatest number of seedling evaluated in the US; not only are large seedling populations evaluated, but several thousand of cross combinations. Therefore, this affords us a greater opportunity to produce superior cultivars by evaluating a diversity of germplasm. Boulder, Tablestock and chip-processing with excellent quality attractive large white skin and tubers; Dakota Jewel, Tablestock with early maturity, medium yields good culinary quality; Freedom Russet, Dual purpose exceeding Russet Burbank in US#1 yield, with resistance to scab, Verticillium and early blight; Jacqueline Lee, Tablestock selection with smooth, attractive appearance that has foliar resistance to the US8 genotype of late blight; Liberator, Chip-processing from 5ºC with strong scab resistance; Megachip, Chipping with early tuber bulking and resistant to scab and has good chip color from 5ºC storage; Michigan Purple, Tablestock with excellent quality attractive purple skin and white for the fresh market; Millennium Russet, Dual purpose russet with superior tuber appearance good specific gravity and superior fry quality after 45ºF storage. It is medium resistant to scab, PVY and early blight; MSG227-2, Chip-processing with cold-storage potential and scab resistance; MSJ461-1, Chip-processing with strong foliar resistance to late blight; MN 15620, Processing clone with yellow flesh and resistance to PVY and PLRV; MN 18747, Processing clone better than Shepody with white skin and flesh, early maturity and expresses normal symptoms of PVY and PLRV infection unlike Shepody; ND2470-27, Chipping and fresh with round, smooth tubers and white skin, white flesh and shallow eyes that chips from 5ºC; ND5822C-7, Chipping from 5ºC with high yields round, smooth tubers with bright white skin and flesh, and CPB field tolerance; White Pearl, Chipping with resistance to cold sweetening at 5ºC; Villetta Rose, Tablestock red with very uniform tubers with stable dark red color and great appearance with shallow eyes and excellent organoleptic traits for canning; Late blight: EGS for late blight resistance evaluating new hybrid progeny as transplants or seedling tubers shows merit and can accelerate EGS for LB resistance by 2 years. In Michigan, EGS evaluation of foliar late blight reaction increases the efficiency of early generation by allowing the breeder to quickly remove susceptible clones before further time and resources are invested. WI used S. demissum, S. stoloniferum, S. tuberosum ssp. Andigena, and potato-S. bulbocastanum somatic hybrids for LB resistance. Fungicide x variety interactions: Experiments were carried out in MI to evaluate combining host resistance with reduced rates and frequencies of fungicide fluazinam to control foliar potato late blight. The study demonstrates that potato cvs./ABL with reduced susceptibility to late blight can be managed with reduced fungicide rates and longer application intervals, thus offering a less expensive option for potato late blight control. Verticillium wilt and early dying: Verticillium wilt screening can involve several methods; one being sap assay. High within-plant stem-to-stem variation results using this method Knowledge of the seasonal colonization dynamics is needed to better understand the relationships that occur between stem colonization and disease progression. Resistant germplasm was identified to use in breeding programs. In MI, Potato Early-Die Disease Complex (PED) was studied on 24 lines. MSH095-4, FL1879 and W1201 exhibited significant tolerance. Common Scab: A national study indicated that resistance response of clones varies considerably over environments and evaluation at multiple sites is important for identifying clones with stable disease phenotypes. EGS evaluation was initiated at MI and WI and includes field and lab-based assays. Hybrid seedlings evaluated increases annually and EGS coupled with cultural practices resulted in about 20% of the WI lines showing very good resistance. Colorado potato beetle: Insecticide resistance to imidacloprid, appeared for the first time in the Midwest; increasing the likelihood of widespread insecticide failures in future. EGS evaluation of foliar resistance to CPB was conducted throughout the region. MI continues traditionally bred and genetically engineered resistant to CPB. Defoliation was near zero and no CPB larvae survived in field cage studies on lines engineered with Cry3A Bacillus thuringiensis (Bt) as a resistance factor. Lines with Cry1IA1 Bt, bred for resistance to potato tuberworm, reduced defoliation by CPB by >50%. avidin as a resistance factor decreased CPB feeding. Traditionally bred lines showed moderate levels of resistance. Viruses and Aphids: Host resistance for PVY revealed the highly heritable nature of PVY asymptomatic (ASM) expression, the existence of ASM gene(s) in both 2x and 4x potatoes, and ability to transmit these gene(s) by n and 2n gametes. PLRV resistance was found in 16 families. Significant location differences emphasized the inability to select for PLRV resistance without a post-harvest storage interval. Studying aphid behavior is critical to decreasing agro-chemical use promoting sustainable farming. Results have facilitated reduced insecticidal use by site-specific application, new knowledge on the epidemiology of potato viruses and expanded host range of green peach aphid to soybean, and geographical/environmental/meteorological influence on aphid population dispersal. MN has identified 20 clones that consistently express field resistance to PVY and PLRV; PVY resistance protect against all PVY strains known to occur in Minnesota (PVYO, PVYN, PVYNTN, and PVY O:N recombinants). Of the 20 PVY and PLRV resistant lines, one (designated JAD24) has shown resistance to both green peach aphid (Myzus persicae) and potato aphid (Macrosiphum euphorbiae). Line JAD24 was identified as containing both Ryadg and Rysto as well as PLRV.1, a marker for PLRV resistance. JAD24 lacks the Mi gene from Lycopersicon esculentum but contains markers for Potato virus S and Globodera pallida resistance. JAD24 has been crossed with cv. Chieftain to produce an F1 population, designated HPR, and 100 of 300 seeds have been grown out. Bacterial ring rot: Foliar symptoms of BRR, were present in all 23 inoculated selections by 90 DAP, except MI selection JACQUELINE LEE, which failed to display characteristic foliar symptoms of BRR. Remaining selections exhibited characteristic tuber and foliar symptoms. Cold sweetening resistance: The inheritance and predictability of two biological markers to identify clones with potential to resist cold sweetening (CS) by evaluating A-I and/or A-II isozymes of UGPase established that based on the correlation of chip color score with isozyme profiles and BAcInv activity, the families could be grouped into the following four distinct classes. The primary factor predicting resistance was the level of BAcInv activity. In EGS the optimum sample size of one slice from one tuber reduces type I errors, discarding clones that should be retained. EGS for CS resistance resulted in greatest genetic gain from 4x-4x crosses; but, significant improvement for CC coupled with disease resistance was from 2x potato species. Two species, S. raphanifolium and S. sparsipilum, had CC ability and late blight resistance; 232 clones were selected from these species crosses. Cultural management and N utilization: MI determined variety response to four nitrogen levels at moderate-high plant densities. Variety determined yield and tuber quality response showed highly significant interactions with nitrogen and density. Consistently low yields resulted from application of slow-release fertilizer at the 180 lb N/acre, however this was the most environmentally-friendly treatment associated with the lowest level of residual nitrate-N in the soil profile after harvest. The poultry manure + fertilizer treatment was the best economic option in terms of optimizing both yield and reduced soil profile nitrate-N. The highest yield response of chipping genotypes was from UEC and MSJ461-1; tablestock genotype Michigan Purple showed high yield potential across all management regimes evaluated. Overall, clones differed in N response and less N will be recommended in production practices. Twenty-four novel sexual diploid and triploid inter-series hybrids were generated from wild species crosses by using post-pollination applications of auxin and embryo rescue in vitro representing the first step in overcoming post-zygotic reproductive barriers among isolated species. Transgenic approaches offer breeders opportunity to combine novel traits or resistance mechanisms that may not be possible through conventional approaches. MI has obtained the RB gene from Dr. Jiang and transformations introduced this gene in susceptible and resistant lines for LB resistance. Along with these transformations, we are exploring transformation strategies to create marker-free transgenic plants.

Publications of NCR-84 participants Bamberg, J.B. and A.H. del Rio. 2004. 2004. Genetic heterogeneity estimated by RAPD polymorphism of four tuber-bearing potato species differing by breeding system. Am. J. Potato Res. 81:377-383. Brown, C.R., H. Mojtahedi and J. Bamberg. 2004. Evaluation of Solanum fendleri as a source of resistance to Meloidogyne chitwoodi. Am. J. Potato Res. 81:415-419. Busse, James S., John B. Bamberg and Jiwan P. Palta. 2004. Genetic variations for calcium accumulation efficiency in tuber and aerial shoot tissues. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 36. (Abstract) Chen, Q., D. Lynch, H.W. (Bud) Platt, H.Y. Li, Y. Shi, H.J. Li, D. Beasley, L. Rakosy-Tican, and R. Theme. 2004. Interspecific crossability and cytogenetic analysis of sexual progenies of Mexican wild diploid 1EBN species Solanum pinnatisectum and S. cardiophyllum. Am. J. Potato Res. 81:159-169. Chen, Q., S. Sun, Q. Ye, S. McCuine, E. Huff, and H.B. Zhang. 2004. Construction of two BAC libraries from the wild Mexican diploid potato, Solanum pinnatisectum, and the identification of clones near the late blight and Colorado potato beetle resistance loci. Theor. Appl. Genet. 108(6):1002-1009. Coombs, Joseph, David Douches, Susannah Cooper, and Edward Grafius. 2004. Colorado potato beetle and potato resistance mechanisms: more than just a defoliation issue. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 54. (Abstract) del Rio, Alfonso and J.B. Bamberg. 2004. Ten years of research at the US Potato Genebank using molecular markers to study efficiency in the acquisition and management of Potato Genetic Diversity. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 77. (Abstract) del Rio, Alfonso, J.B. Bamberg and Z. Huaman. 2004. Assessment of putative identical germplasm collections at CIP and US Potato genebanks determined by RAPD and SSR markers. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 32. (Abstract) Douches, David S. and Kelly Zarka. 2004. Engineered approaches to develop potatoes for sub-optimal irrigation conditions. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 57. (Abstract) Fernandez, Charles J. and John B. Bamberg. 2004. A new Solanum fendleri mutant lacking purple pigment. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 78. (Abstract) Frost, K.E., D.I. Rouse and S.H. Jansky. 2004. Distributional dynamics of Verticillium dahliae in potato plant tissue through the growing season. Phytopathology 94:S32. Ghislain, M., D.M. Spooner, F. Rodriguez, F. Villamon, J. Nunez, C. Vasquez, R. Waugh, and M. Bonierbale. 2004. Selection of highly informative and user-friendly microsatellites (SSRs) for genotyping of cultivated potato. Theor. Appl. Genet. 108:881-890. Gonzales-Vigil, Eliana, Kelly Zarka, Pavani Tumbalum, Willie Kirk, and David Douches. 2004. Combining engineered and natural host plant resistance to Phytophthora infestans in cultivated potato. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 80. (Abstract) Groza, H.I., B.D. Bowen, D. Kichefski, S.J. Peloquin, and J. Jiang. 2004. Red Pearl: A new gourmet red potato variety. Am. J. Potato Res. 81:209-213. Hannapel, David J., Hao Chen, Faye M. Rosin, Anjan K. Banerjee, and Peter J. Davies. 2004. Molecular controls of tuberization. Jansky, S.H., D.I. Rouse and P.J. Kauth. 2004. Inheritance of resistance to Verticillium dahliae in diploid interspecific potato hybrids. Plant Disease 88:1075-1078. Jansky, S.H., E.D. Mauritz, J.J. Clark, and D.I. Rouse. 2003. Disease resistance in potato haploids. In: Potatoes  Healthy food for Humanity: Internatl Developments in Breeding, Production, Protection and Utilization. Proc. of XXVI Internatl Hort. Congress, Toronto, Canada, Aug. 11-17, 2002. (Ed: R.Y. Yada). Acta Hort. 619:135-144. Jansky, S.H., G.L. Davis and S.J. Peloquin. 2004. A genetic model for tuberization in potato haploid-wild species hybrids grown under long-day conditions. Am. J. Potato Res. 81:335-339. Jansky, Shelley. 2004. Resistance to white mold in wild Solanum species. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 59. (Abstract) Karlsson, B.H. and J.P. Palta. 2003. Enhancing tuber calcium by in-season calcium application can reduce tuber bruising during mechanical harvest. In: Potatoes  Healthy food for Humanity: Internatl Developments in Breeding, Production, Protection and Utilization. Proc. of XXVI Internatl Hort. Congress, Toronto, Canada, Aug. 11-17, 2002. (Ed: R.Y. Yada). Acta Hort. 619:285-291. Knapp, S., L. Bohs, M. Nee, and D.M. Spooner. 2004. Solanaceae  a model for linking genomics with biodiversity. In: Plant & Animal Genome XII Conference, San Diego, CA, January 10-14, 2004. Comp. Func. Genomics 5(3):285-291. Lynch, D.R., L.M. Kawchuk, Q. Chen, J. Wahab, M. Konschuh, D. Waterer, J. Holley, D.K. Fujimoto, D. Driedger, H. Wolfe, L. Dunbar, P. Bains, and P. McAllister. 2004. Pacific Russet: An early maturing, attractive russet cultivar with excellent culinary quality. Am. J. Potato Res. 81:235-241. Lynch, D.R., L.M. Kawchuk, Q. Chen, M. Konschuh, J. Holley, D.K. Fujimoto, D. Driedger, H. Wolfe, L. Dunbar, D. Waterer, P. Bains, J. Wahab, and P. McAllister. 2004. Alta Russet: An early-maturing, high-quality russet cultivar for wedge-cut french fry production. Am. J. Potato Res. 81:195-201. Lynch, D.R., Q. Chen, L.M. Kawchuk, and D. Driedger. 2004. Verticillium wilt resistant germplasm-release of clone LRC18-21 and derivatives. Am. J. Potato Res. 81:295-297. Miller, J.C., Jr., G.C.C. Tai, B. Ouellette, and J.P. Miller. 2004. Discriminating Russet Norkotah intraclonal selections using canonical and cluster analysis. Am. J. Potato Res. 81:31-35. Mollov, Dimitre S. and Christian A. Thill. 2004. Evidence of potato virus Y asymptomatic clones in diploid and tetraploid potato-breeding populations. Am. J. Potato Res. 81:317-326. Ortiz, R. and A.M. Golmirzaie. 2004. Genotype by environment interaction and selection in true potato seed breeding. Experimental Agriculture 40(1):99-107. Serquen, F.C. and R.E. Hanneman, Jr. 2002. An analysis of the hybrid nature of Solanum x edinense Berth. Using molecular, cytological and crossability studies. Potato Research 45:85-97. Sowokinos, J., C.A. Thill, I. Shea, and K. Novak. 2004. Use of UDP-Glucose pyrophosphorylase (UGPase) isozymes profiles and basal acid invertase activity to select for potato germplasm resistance to cold-induced-sweetening (CIS). Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 38. (Abstract) Spooner, D.M. and K.A. Williams. 2004. Germplasm acquisition. Encyclopedia of Plant and Crop Science, Ed.: R.M. Goodman, 537-540. Dekker Agropedia, New York, New York. Spooner, David and W.L.A. Hetterscheid. 2004. Cultivar-group classification of modern cultivated potato. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 47. (Abstract) Spooner, David and W.L.A. Hetterscheid. 2004. Origin of the modern cultivated potato. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 47. (Abstract) Suttle, Jeffrey C. 2004. Physiological regulation of potato tuber dormancy. Am. J. Potato Res. 81:253-262. Tai, G.C.C. and T.R. Tarn. 2003. Evaluation of varieties: genotypes, environments and genotype-environment interactions. In: Potatoes  Healthy food for Humanity: Internatl Developments in Breeding, Production, Protection and Utilization. Proc. of XXVI Internatl Hort. Congress, Toronto, Canada, Aug. 11-17, 2002. (Ed: R.Y. Yada). Acta Hort. 619:31-34. Tarn, T.R., A.M. Murphy, D.H. Wilson, V.J. Burns, and K.G. Proudfoot. 2003. Multiple resistance to diseases in a population of long-day adapted Andigena potatoes. In: Potatoes  Healthy food for Humanity: Internatl Developments in Breeding, Production, Protection and Utilization. Proc. of XXVI Internatl Hort. Congress, Toronto, Canada, Aug. 11-17, 2002. (Ed: R.Y. Yada). Acta Hort. 619:189-194. Vega, S.E., A.H. del Rio, J.B. Bamberg, and J.P. Palta. 2004. Evidence for the up-regulation of stearoyl-ACP (?9) desaturase gene expression during cold acclimation. Am. J. Potato Res. 81:125-135. Vega, S.E., J.B. Bamberg and J.P. Palta. 2004. Characterization of gibberellin requirements for various diploid and tetraploid gibberellin deficient mutants. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 60. (Abstract) Vega, S.E., J.P. Palta and J.B. Bamberg. 2004. Evidence for the mitigation of gibberellin deficiency symptoms by root zone calcium in GA-deficient mutants of potato. Presented at 88th Annual Meeting of PAA, Scottsbluff, NE, Aug. 8-12, 2004. p. 61. (Abstract) Zlesak, David C. and Christian A. Thill. 2004. Foliar resistance to Phytophthora infestans (Mont.) de Bary (US-8) in 13 Mexican and South American Solanum species having EBNs of 1, 2, and 4 and implications for breeding. Am. J. Potato Res. 81:421-429.