Donna: A yellow-fleshed potato cultivar with potential in export seed markets

Donna is a smooth, yellow-skinned, yellow-fleshed potato cultivar of Kennebec maturity. It has significant levels of resistance to Verticillium wilt, PVX, PVY and to the North American pathotype of the potato cyst nematode. Adaptation trials conducted in several countries indicate Donna may have potential in the export seed market.     

Huckleberry Gold: A Specialty Market Potato Cultivar with Purple-Skin,Yellow-Flesh,High Tuber Antioxidants,and Resistance to Potato Cyst Nematode (H1) and Potato virus X (Nb and Rx1)

Huckleberry Gold is a purple-skin, yellow-flesh fresh market cultivar with similar culinary qualities to the market standard Yukon Gold. It has lower specific gravity, sucrose and vitamin C content, but a significantly higher level of tuber antioxidants than Yukon Gold. Notable disease resistant characteristics are Potato virus X resistance based on the presence of molecular markers for the PVX resistance genes, Nb and Rx1. In addition it also has the H1 gene present which confers resistance to the potato cyst nematode, Globodera rostochiensis, which has been confirmed by bioassay to pathotype Ro1. The size profile of Huckleberry Gold is smaller than Yukon Gold, allowing a better fit into specialty markets that are geared to smaller size for fresh use. Huckleberry Gold represents the first purple-skin, yellow-flesh cultivar to come from the Northwest (Tri-State) Potato Variety Development program.     

Resistance to <Emphasis Type="Italic">Potato virus Y</Emphasis> in a Multitrait Potato Breeding Scheme without Direct Selection in Each Generation

In an experimental breeding scheme to improve late blight (Phytophthora infestans) and white potato cyst nematode (Globodera pallida) resistance of tetraploid potato over three generations of crossing and selection, 15 clones survived the final selection, and these were derived from 15 great-grandparents. There was no direct selection for resistance to Potato virus Y (PVY), but 14 out of the 15 great-grandparents were resistant to PVY and three had extreme resistance. Thirteen of the 15 descendants had PVY resistance and one extreme resistance. This was within the range expected for a random (unselected) sample from the genotypes of the great-grandparents. Hence, we found no evidence for any positive or negative association between PVY resistance and the attributes selected. The conclusion is that laborious selection is not required in every generation when many parents have PVY resistance, including some with more than one copy of a PVY resistance gene or resistance at more than one locus. However, in the future, determining the major virus resistance genes present in potential parents in each generation using diagnostic molecular markers would prevent susceptible × susceptible crosses being made and maximise the number of resistant × resistant ones.     

The incorporation of resistance toGlobodera Pallida intoSolanum Tuberosum germplasm adapted to North America 1

Potato seeds of 24 families consisting primarily ofSolanum tuberosum ssp.andigena with someS. vernei germplasm that were segregating for resistance to potato cyst nematodes (Globodera pallida races P₄A and P₅A andG. rostochiensis race R₁A) were obtained from the International Potato Center. These seeds produced 468 clones with sufficient tubers for evaluation for resistance toG. pallida races P₄A and P₅A in pot tests at the International Potato Center. Twenty-six of these clones, selected for a high degree of resistance toG. pallida races P₄A and P₅A, were crossed with neotuberosum ×Solanum tuberosurn hybrids that had been selected for resistance toG. rostochiensis race R₁A (golden nematode) and the viruses PVX and PVY. The resultant progenies possessed a high degree of resistance to all three races of the potato cyst nematode. From these progenies, 23 clones were selected for resistance to the three races (G. pallida P₄A and P₅A,G. rostochiensis R₁A) of potato cyst nematodes. The better adapted clones with resistance to the 3 races of potato cyst nematodes will be used in the next cycle of back-crossing.     

The production of dihaploids and tetraploids with combined quantitative resistance to potato cyst nematode (Globodera pallida) and foliage blight (Phytophthora infestans)

Summary Dihaploids were produced from tetraploids which had resistance to foliage late blight (P. infestans) and had a range of levels of resistance to white potato cyst nematode (PCN) (G. pallida). Twelve of 33 dihaploids tested had useful levels of both resistances, 11 were resistant to blight alone and seven to PCN alone. There were no significant correlations between the resistances of the parents and the mean resistance of their dihaploids, for either character. There was also no correlation between levels of resistance to blight and to PCN. There were significant differences in mean levels of resistance to blight and to PCN between the tetraploid progenies of two dihaploids which possessed combined resistance.     

Potato cultivar response to late blight as affected by clonal selection andin vitro culture

Response to foliar late blight for Superior and Sebago was not affected by the two potato seed selection and multiplication methods. Kennebec and Russet Burbank potato plants derived throughin vitro tissue culture techniques had significantly more late blight damage on only 4 of 7 and 2 of 7 observation dates, respectively, than plants derived through a clonal selection system. In practical terms, the disease response differences between the two seed propagation methods were minimal. Similarly, disease response differences among the 2 and 3 years of field multiplication for Russet Burbank and Kennebec, respectively, did not demonstrate any significant disease response trends. In general,in vitro culture plots had slightly higher yields than clonal plots but only Kennebec had a significant yield response. The incidence of late blight storage rot was generally not significantly different but clonally selected Kennebec potatoes had significantly more disease than those produced throughin vitro culture.     

Foliar reaction toPhytophthora infestans in inoculated potato field trials in Michigan

Late blight, caused byPhytophthora infestans, is the most important disease of potato worldwide and foliar resistance is an important component of managing late blight in the field. The objective of this research was to identify germplasm for use in breeding cultivars with foliar resistance toP. infestans. More than 500 clones were tested from 1997 to 2002 in inoculated (US8 genotype) field experiments conducted at the Michigan State University Muck Soils Research Farm in Bath, Michigan. All of the current commercial cultivars tested were classified as susceptible toP. infestans. The most resistant clones were A90586-11, AWN86514-2, B0718-3, Jacqueline Lee (MSG274-3), MSI152-A, MSJ307-2, MSJ317-1, MSJ453-4Y, MSJ456-2, MSJ456-4, MSJ461-1, MSK101-2, MSK128-1, NY121, LBR8, LBR9, Tollocan, and Torridon. Some of these resistant selections were from crosses with B0718-3, Jacqueline Lee, and Tollocan suggesting that the resistance toP. infestans was transmissible. These resistant clones will provide the opportunity to breed late-blight-resistant cultivars from a diverse pool of cultivated germplasm. Consistent foliar reaction toP. infestans over years suggested that the Michigan State University Muck Soils Research Farm is a valuable location for North American breeders to assess the reaction of potato germplasm to the US8 genotype of late blight.     

Dakchip: A white-skinned chipping cultivar

North Dakota State University announces the name of a new potato to be called Dakchip. Dakchip is a medium maturing cultivar with chip quality quite comparable to Norchip but better than Kennebec. This new cultivar has round to oblong white skinned tubers and has an excellent plant type and growth. Dakchip is comparable to Kennebec in yield but higher than Norchip. Dakchip has moderate resistance to late blight but is susceptible to most potato viruses and some races of scab.     

Extreme resistance to infection by potato virus Y and potato virus X in an advanced hybridSolanum phureja — S. Stenotomum diploid potato population

Samples of 4285 individuals from a hybridSolanum phureja Juz. et Buk. —S. stenotomum Juz. (Phu-Stn) and 105 individuals ofSolanum phureja (Phu) diploid potato populations were twice inoculated with potato virus Y strain “o” (PVY°) using the air brush technique. After discarding seedlings with PVY visual symptoms both in the greenhouse and in the field, 1508 seedlings were judged to be resistant to PVY° (35.2%). Only 5.7% of the Phu seedlings were PVY° resistant compared to 35.2% of the Phu-Stn seedlings. At harvest, a mild selection pressure for yield and tuber appearance was applied and 602 Phu-Stn clones were chosen for further evaluation. Selected clones were re-evaluated for PVY° resistance in the greenhouse. Clones were mechanically inoculated twice with PVY°. Clones susceptible to PVY° were determined by visual observations, ELISA (Enzyme-linked immunosorbent assay) tests, grafting of tobacco PVY° infected shoots on potato clones, and infectivity tests usingNicotiana tabacum as a PVY° plant indicator. In the process, 224 clones were found to be extreme resistant to infection by PVY°, with an overall frequency for PVY° extreme resistance of 5.2%. In another experiment, the first year Phu-Stn PVY° resistant clones (554 clones) were mechanically inoculated twice with “common” strain of potato virus X (PVX). Similarly, we discarded clones susceptible to PVX by combining visual evaluation and ELISA with PVX re-inoculation of negative clones and an infectivity test, usingGomphrena globosa as a PVX plant indicator. After this process, seven extreme resistant and eight resistant clones to infection by PVX were found; the overall frequency of PVX extreme resistance was 1.3%. Five clones were extreme resistant to both PVY° and PVX.     

Utilization of potato genetic resources in variety development

Potato varieties of Europe, widely grown prior to the late blight epidemic of the 1840s, were apparently derived mainly from ChileanSolanum tuberosum Group (Gp) Tuberosum and with contributions from Gp Andigena. A small number of these old varieties had field resistance and consequently survived the late blight. These survivors, along with a limited number of 19^th and early 20^th century introductions, provided the very narrow genetic base for our modern potato variety development. Beginning in the first half of the 20th century, resistance to diseases and pests from exotic species and primitive relatives was backcrossed into the existing parental stocks, with little improvement in broadening of the genebase. By the 1980s, 77% of European and somewhat fewer North American varieties had genes, derived by backcrossing, fromS. demissum (late blight resistance) and Andigena (resistance to cyst nematode). Broadening of the Tuberosum genebase was undertaken in 1959 by creating long-day adapted Neo-Tuberosum (N-T) from large populations of Andigena. This took six or more cycles of recurrent mass selection. Simmonds, in England, was the first to begin this work, followed shortly after by Plaisted, in the U.S., and Tarn, in Canada. Varieties with N-T in their pedigrees include the New York releases “Rosa”, which is 50% N-T, and “Eva”, 25% N-T. The Tuberosum genebase has also been broadened with diploid Gp Phureja resulting in the releases of “Yukon Gold,”with yellow flesh and high internal quality, and “NorValley,”a chipper with resistance to cold sweetening. Over 5000 accessions of about 150 wild species are available to breeders from the U.S. Department of Agriculture, National Research Support Project 6 (NRSP-6) genebank. Many of these accessions have been evaluated for resistance to diseases and pests as well as other important traits. Six genebanks in other countries also have many accessions for breeders. These seven collections are a great source of valuable traits for breeding, but remain under-utilized, mainly because of the time and additional resources required in eliminating the “wildness”characters associated with the desired traits. “Pre-breeding”is needed to help breeders utilize the many needed genes and alleles in the wild species. There now are two projects with pre-breeding as an objective in the U.S., one at Madison, WI, and the other at Prosser, WA. Resistance to cold sweetening (low sugar build up in cold storage) has been backcrossed from several wild species into the Tuberosum background, as has resistance to late blight, the Columbia rootknot nematode, and the potato leafroll virus (PLRV). Resistance to potato virus Y (PVY) and PLRV obtained from N-T has been incorporated into Tuberosum parental stocks. Durable resistance to late blight in Polish breeding stocks, withS. demissum andS. stoloniferum background, and in improved Bolivian and Peruvian Andigena has also been utilized by North American programs.     

Alturas: A multi-purpose, Russet potato cultivar with high yield and tuber specific gravity

‘Alturas’, a late-maturing, high-yielding, russet potato cultivar with high tuber specific gravity, was released in 2002 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington. Originally selected for dehydration processing, its cold-sweetening resistance also makes it suitable for processing out of storage into french fries and other frozen potato products. Culinary quality is high, with larger tubers suitable for fresh market if heavily russeted skin is not essential. Alturas consistently produced greater total and U.S. No. 1 yields than ‘Russet Burbank’ and ‘Ranger Russet’ in southern Idaho trials. Across other western trial sites, total yields of Alturas have on average been 29% and 14% greater than Russet Burbank and Ranger Russet, respectively. Alturas is resistant to Verticillium wilt (Verticillium dahliae) and early blight (Alternaria solani). Compared with Russet Burbank and Ranger Russet, Alturas is less susceptible to corky ringspot and foliar and tuber infection by late blight (Phytophthora infestans). It also is less susceptible to tuber net necrosis and Fusarium dry rot than Russet Burbank, and is more resistant to common scab (Streptomyces scabies) than Ranger Russet. However, Alturas is more susceptible to infection by PVY and PVX than Ranger Russet. Total nitrogen application recommendations for Alturas are approximately 40% less than those for Russet Burbank. Alturas requires 15% to 20% more water during the growing season than does Russet Bur-bank.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Eva:A midseason golden nematode- and virus-resistant variety for use as tablestock or chipstock

Eva is a new potato variety being released by the New York and Pennsylvania Experiment Stations. Eva is notable for its bright clear skin and attractive round to oval shape. It produces a chip color comparable to Monona from 9 C storage and has specific gravity 014 less than that of Atlantic. It has exceptionally long tuber dormancy and has extreme resistance to PVX, PVY, and race RO1 of the golden nematode. Scab resistance is like that of Monona. It is expected that Eva will find primary acceptance as a tablestock variety.     

Inheritance of early blight resistance from open-pollinated 4×-2× potato hybrids

Early blight, caused byAlternaria solani Sorauer, is a serious disease of potatoes that occurs in most potatogrowing regions in the world. There is little resistance to early blight among commercial potato cultivars. However, resistance to early blight in diploid (Solanum phureja-S. stenotomum) potatoes has been identified, and was found to be highly heritable and readily transferred to the tetraploid level via4×-2× crosses. The purposes of this study were to identify good levels of early blight resistance in open-pollinated4×-2× (Solanum tuberosum×S. phureja-S. stenotomum) hybrids selected for horticultural characteristics, to estimate broad-sense heritability for early blight resistance in these hybrids, and to investigate the general and specific combining ability for resistance to early blight from some of these early blight resistant tetraploid selections. Four early blight resistant clones were crossed as female parents with four different male parents in a design II mating scheme to generate 16 families. Approximately 20 randomly chosen offspring per family were visually evaluated for early blight resistance in 1995 and 1996 in a randomized complete block design in Pennsylvania. Broad-sense heritability for early blight resistance among the open-pollinated4×-2× hybrids which were originally selected for horticultural characteristics was 0.91 with a 95% confidence interval of 0.80, 0.94. There were significant differences among female and male parents for area under the disease progress curve, indicating the importance of general combining ability for early blight resistance in this germplasm. The female x male source of variation was not significant, indicating that specific combining ability was not important. The greatest number of resistant progeny were observed in families where both parents were derived from the early blight resistant population; however, at least one highly resistant progeny was produced in all families. These results suggest that the early blight resistance in these clones can be readily incorporated into the commercial tetraploid breeding population.     

The origin and distribution of the golden nematode and its potential in the U.S.A.

Potato cyst-nematodes,Globodera pallida andG. rostochiensis (golden nematode), and their preferred host, the potato, originated in the Andes of South America. Both were introduced into Europe from the Andean region, the potato about 1570 and the nematode nearly 300 years later. Potato cyst-nematodes are believed to have been introduced into Europe in the 1850’s along with potato collections from the Andes for use in breeding for late blight resistance, but the nematodes went unnoticed until 1881. Since that time the nematodes have spread to virtually everywhere that potatoes are grown, as one or both species have now been reported from 47 countries. It is believed that the golden nematode was introduced into the U.S.A. from Europe on military equipment brought back after the First World War to Long Island, NY, but the nematode was not recognized until some 20 years later. Yield losses in countries with general infestations of potato cyst-nematodes are probably 9% or more; the potential for losses is greatest in countries where average yields are greatest, such as the U.S.A. Good resistance to the pathotype of the nematode that occurs in the U.S.A. is commercially available. If all potatoes grown in the U.S.A. contained this resistance, further spread would be restricted and the golden nematode could perhaps be eliminated from the U.S.A.; but the present supply and diversity of resistant varieties are insufficient for the total potato acreage. Restricting spread of the golden nematode in the U.S.A. minimizes costs borne by growers and government agencies in dealing with the pest. At present, the most promising approach to restricting spread is through management systems developed for keeping nematode densities below the critical level above which spread will occur. If the golden nematode is to be contained, management systems must eventually be applied to all potato acreages. Increased research effort is needed to develop resistant varieties, resistance to a broad range of pathotypes, nematode management systems, and biological control     

墨西哥野生马铃薯Solanum pinnatisectum抗晚疫病及抗马铃薯甲虫新基因的遗传分析与分子标记(英文)

马铃薯晚疫病(Phytophthora infestans)和科罗拉多马铃薯甲虫(CPB)是马铃薯生产中最为严重的病虫害。培育高抗晚疫病和甲虫的马铃薯品种是加拿大马铃薯育种工作的重要组成部分。目前,我们实验室在二倍体1EBN墨西哥野生种中已鉴定出抗马铃薯晚疫病和甲虫的新基因,并利用原生质体融合技术成功的将其转移到栽培品种中。但是,培育出抗晚疫病和抗甲虫的马铃薯新品种仍然是一项艰难而繁杂的工作。为了加快分离抗性基因,建立与抗性基因紧密关联的DNA分子标记至关重要。本研究以感病的二倍体马铃薯品种S.cardiophyllum作为父本,与带有抗性基因的墨西哥野生种S.pinnatisectum杂交。用叶片离体鉴定的方法测试F1和BC1代群体的抗病性,从而筛选抗晚疫病和抗甲虫的植株。US-8/A2交配型病菌测试显示所有的F1代植株都表现出抗晚疫病,而在BC1群体中抗病与感病植株的比例为1:1。这个结果证明,在墨西哥野生种S.pinnatisectum中存在一个抗晚疫病的单显性基因Rpi1。马铃薯甲虫抗性检测中,BC1群体的抗虫性分离比例为1:3.这表明其对甲虫的抗性是由多基因遗传控制的。在F1和BC1群体中利用分子标记结合集团分离分析法(BSA)对S.pinnatisectum中的晚疫病抗性基因Rpi1进行精细作图。根据马铃薯第7条染色体上RFLP标记TG20A和CP56之间的EST和STS标记的序列信息,合成了27对特异性PCR引物。获得一些与抗晚疫病基因Rpi1相关联的新的DNA标记。对BC1群体中大量的个体植株进行的分析表明,在马铃薯第7条染色体上位于抗晚疫病基因Rpi1两侧的两个标记S1c9和GP127-300,它们与Rpi1基因的遗传距离分别为1.17cM和3.89cM。这些标记被用来筛选两个细菌人工染色体(BAC)文库,并分离出与晚疫病抗性相关的90-125kb的BAC克隆,这些克隆将在后续的工作中通过图位克隆的方法而用于分离晚疫病抗性基因。同时分离与甲虫抗性紧密相关的分子标记的工作正在进行中。     

Performance of populations derived by selecting for resistance to potato leafhopper in A 4XSolanum Tuberosum X 2XSolanum Chacoense cross

Intercross and backcross populations derived from aSolanum tuberosum L. (2n = 2x = 48) ×Solanum chacoense Bitt. (2n = 2x = 48) cross by selecting for resistance to potato leafhopper (PLH) (Empoasca fabae Harris), were tested in the field. In F2 and F4 populations, the levels of nymphal infestation and leaf necrosis from PLH feeding were considerably lower and tuber yields were much lower compared with those measured on the susceptible cultivar Kennebec. No differences were found between the two populations. Backcrosses of the F2 and F4 populations toS. tuberosum decreased resistance to PLH. Resistance to infestation was still greater than that of Kennebec; severity of leaf necrosis equaled that of Kennebec. Tuber yields increased, but were less than Kennebec’s yield. Foliage types shifted closer to those ofS. tuberosum. Three generations of selection and intercrossing within the backcross populations did not change the level of resistance to PLH but did tend to lower tuber yields. Foliage types remained primarilyS. tuberosum in appearance although distinctive types segregated with increased frequency. A second backcross toS. tuberosum did not change the level of resistance to PLH or the level of tuber yield relative to those of the first backcross or Kennebec.     

Identification of late blight, Colorado potato beetle, and blackleg resistance in three Mexican and two South American wild 2x (1EBN)Solanum species

Wild potatoes are important sources of genes for resistance to disease and insect pests. A collection of wild Mexican and South AmericanSolarium species from the US potato Genebank was evaluated under laboratory and/or field conditions for their reaction to late blight (Phytophthora infestans), Colorado potato beetle (CPB,Leptinotarsa decemlineata Say), and blackleg (Erwinia carotovora subsp.atroseptica (van Hall) Dye) in order to identify individual genotypes with multiple resistance genes. Late blight inoculations using aggressive isolates (US-8/A2 and US-11/A1 mating types) of P.infestans revealed a wide range of variation for resistance between and within the accessions of the wild species tested. For late blight, susceptible as well as moderately to highly resistant genotypes were observed in all the species tested. However, at least one accession from the three Mexican and one South American wild diploid species tested showed a relatively uniform high level of resistance toP. infestans. These includedS. bulbocastanum, S. pinnatisectum, S. cardiophyllum, andS. circaeifolium. Two accessions from South American speciesS. commersonii were highly susceptible to late blight. For the Colorado potato beetle test, only one species,S. pinnatisectum appeared uniformly resistant to CPB under field conditions. Results of screening for blackleg resistance showed that there were major differences between genotypes in the wild species. Accessions ofS. circaeifolium PI 498119 andS. bulbocastanum PI 243504 were identified as having significantly higher blackleg resistance than cultivated potato and the other wild species tested. However, genotypes from these two accessions were more susceptible to late blight and CPB. Characterization of theP. infestans isolate P1801C.16 used for late blight evaluation and multi-locus isolate tests using US-8/A2 and US-11/A1 races revealed that the resistance inS. pinnatisectum genotypes tested corresponded to a race-non-specific genetic system, which was different from any existing R genes.Solanum pin-natisectum genotypes with both high levels of late blight and CPB resistance as well as blackleg resistance genotypes identified in the present study represent a diverse gene pool that may be useful for development of new potato cultivars with multiple disease and insect resistance. The potential utilization of these valuable sources for improvement of cultivated potato is discussed.     

Hampton: A main season golden nematode resistant variety

Hampton is a golden nematode resistant variety suited for main season tablestock production. It is resistant toVerticillium wilt, but susceptible to scab and late blight. Hampton yields as well as Katahdin and produces essentially the same distribution of tuber sizes. Its shape is distinctively spherical with shallow eyes. Its specific gravity is like Katahdin and it will not produce acceptably light colored potato chips.     

Reniform nematode resistance in potato clones

SeveralSolatium tuberosum clones were tested for resistance to the reniform nematode,Rotylenchulus reniformis. Commercial cultivars La Rouge and possibly Red La Soda had high levels of resistance to the reniform nematode.R. reniformis resistance was found to exist independently of the H₁, H₂, or H₃ genes for resistance to races of potato cyst nematodes,Globodera rostochiensis andG. pallida. In addition to reniform nematode resistance, B7642-2, B7154-8 and B7680-6 contained the H₁ gene and breeding linePI 377741 contains the H₁ and H₂ gene for potato cyst nematode resistance. Over a three month period reniform nematode counts were significantly lower in pots where resistant varieties were grown.