Reevaluation of the potato aphid,Macrosiphum euphorbiae (Thomas), as vector of potato virus Y

The effectiveness of the potato aphid,Macrosiphum euphorbiae (Thomas), to transmit potato virus Y (PVY) to potato has generally been overestimated because tobacco has been used as the indicator host. Our results demonstrate that, although apterousM. euphorbiae can acquire PVY from potato and tobacco plants and transmit it to tobacco plants, it does not readily transmit it to potato plants. Alatae only transmitted the virus to 4.5% of potato plants. This relative inability to transmit the virus to potato seems independent of potato cultivar. Results suggest that the role of the potato aphid in the spread of PVY in potatoes may be negligible.     

Genetic Resistances to Potato Leafroll Virus, Potato Virus Y, and Green Peach Aphid in Progeny ofSolanum etuberosum

Increasing prevalence of potato leafroll virus (PLRV) and potato virus Y (PVY) has been reported in seed and commercial potato production, resulting in the rejection of potatoes for certification and processing. Host plant resistance to PLRV and PVY and their primary vector, green peach aphid,Myzus persicae, could limit the spread of these viruses. Host plant resistance to PLRV, PVY, and green peach aphid has been identified in non-tuber-bearingSolanum etuberosum (PI 245939) and in its backcross 2 (BC₂) progeny. Resistance to green peach aphid involved a reduction in fecundity and adult aphid size. In addition, one BC₂ individual was identified as possessing a genetic factor that was detrimental to nymph survival. PVY resistance was identified in all five BC₂ progenies evaluated in a field screening under intense virus pressure. PLRV resistance was identified in two of the five BC₂ progeny. This resistance was stable in field and cage evaluations with large populations of viruliferous aphids. Based on the segregation of virus resistances in the BC₂ , PVY and PLRV resistances appear to result from the action of independent genetic mechanisms that reduce the levels of primary and secondary virus infection. Two BC₂ individuals, Etb 6-21-3 and Etb 6-21-5 were identified as having multiple resistances to PLRV, PVY, and green peach aphid derived fromS. etuberosum. This germplasm could prove useful to potato breeders in the development of virus-resistant cultivars.     

Importance and control of potato virus YN (PVYN) in seed potato production

Summary The tobacco veinal necrosis strain of potato virus Y (PVY^N) first became epidemic in several European countries in the 1950s. To prevent PVY^N-infections, account must be taken of virus sources both within and without potato fields; for forecasting, the aphid vector species, their vector efficiency, and their flight activity must all be known. Well-timed haulm destruction needs knowledges of PVY^N-translocation in potato plants and of the development of mature plant resistance. For successful virus control, also reliable methods for virus detection are needed, and for this ELISA has been well established for many years in seed potato certification schemes. A combined treatment of mineral oil and pyrethroids reduces aphid populations and the spread of stylet-borne viruses in the fields. In breeding for resistance, the major gene Ry induces complete protection against infections of all known PVY-strains.     

改进生产马铃薯种薯技术的研究

我国于１９７５年已利用马铃薯茎尖组织培养获得无病种薯．相继在马铃薯主要产区的许多省份内均取得显著的增产就地留种的效应．但获得的无病毒种薯并不是一劳永逸的，因此必须采用综合措施防止无病毒种薯再侵染病毒和其它病原。例如，应用蚜虫飞迁资料控制传播病毒以及将微型薯和小薯种植在防虫温室和防虫网棚内．在种薯检验过程中应利用酶联免疫和往返凝胶电泳跟踪检测，以便在防虫网棚群内采取局部控制，对脱毒小薯进行无性繁系选择．     

Soft-rot Resistance of Coloured Potato Cultivars (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.): The Role of Anthocyanins

Coloured potatoes (Solanum tuberosum L.) rich in anthocyanins are gaining increasing interest on the markets, mainly due to beneficial health effects. Potato varieties containing colour pigments are therefore utilized more and more in actual breeding programmes. In this study, 10 purple-fleshed potato cultivars were compared in their resistance to soft rot caused by Pectobacterium carotovorum (Pc) with 10 white/yellow-fleshed potato cultivars. The results revealed that coloured potato cultivars exhibited on average better resistance to soft rot than white/yellow-fleshed potato cultivars. On tuber halves of purple-fleshed cultivars, the extent of rotting caused by Pc was on average 28.6% lower than on white/yellow-fleshed cultivars. The greater resistance of coloured potatoes coincided with the presence of anthocyanins, higher concentrations of soluble phenols and elevated polyphenol oxidase activity in tuber tissue. These three components were significantly correlated with the extent of rotting caused by Pc. However, coloured and white/yellow-fleshed cultivars were not very different in phenylalanine ammonia-lyase and peroxidase activity. There were also no significant differences in concentrations of dry matter, starch, crude protein and glycoalkaloids. Key findings reveal that total soluble phenols and anthocyanins contributed crucially to resistance expression in tuber tissue of coloured potato cultivars.     

利用体细胞杂交获取马铃薯软腐病的抗性

对马铃薯四倍体栽培种和二倍体野生种Solanumbrevidens的体细胞杂种通过叶片离体培养获得的四倍体植株,以及用四倍体栽培种进行回交获得的五倍体植株的块茎对软腐病的抗性进行了测定。结果表明,由体细胞杂种通过叶片组织离体培养再生植株中,有一个株系SC107对软腐病菌Erwiniacarotovora具有较强的抗性。在用不抗软腐病的马铃薯栽培种对体细胞杂种进行回交获得的杂种后代中,大部分株系对软腐病菌具有高水平的抗性,从而说明Solanumbrevidens对软腐病的抗性基因已转移到马铃薯栽培种。     

A Greenhouse Assay for Powdery Scab (<Emphasis Type="Italic">Spongospora subterranea</Emphasis> f. sp. <Emphasis Type="Italic">subterranea</Emphasis>) Resistance in Potato

The plasmodiophorid pathogen Spongospora subterranea f. sp. subterranea causes powdery scab disease of potatoes (Solanum tuberosum L.), which severely affects tuber quality. Adequate chemical control of the disease is lacking, so breeding resistant potato cultivars is important. Little is known about the mechanisms or genetics of host resistance, as the epidemiology of the pathogen makes research on the disease difficult. An environmentally controlled disease screen that allows the accurate and repeatable assessment of diseased tubers (rather than a ranking system) is required to study host resistance in more detail. A high-throughput greenhouse disease assay is described that has been used to assess varying levels of tuber disease resistance of potato genotypes for three consecutive Southern Hemisphere growing seasons (2001–2002, 2002–2003, 2003–2004). This assay allows the evaluation of symptoms on tubers to verify resistance, rather than inferring the tuber infection on the basis of root galling or zoosporangial root infection. The assay was used to determine the level of resistance of genotypes of both known and unknown resistance status. The assay clearly distinguished the susceptible and resistant standards, and the results were highly correlated over the three seasons. The most efficient ways of assessing tuber disease susceptibility of genotypes are discussed. The consistency of the results and the ability to screen many genotypes confirms the value of the assay as a tool for early-generation selection in a plant breeding programme.     

Interactions betweenPotato leafroll virus and potato plants and their implications for assessment of infection resistance

The effects of Potato leafroll virus (PLRV) isolates and inoculation method on the resistance to PLRV in potato clones and cultivars were investigated. In the season of inoculation, aphid inoculation resulted in higher proportions of infected plants and higher virus concentration in infected plants, as compared to graft inoculation. In these respects, grafting showed superiority over aphid inoculation in the tuber progeny of inoculated plants, though distinct dominance of aphid inoculation was observed for some tested clones. This leads to the conclusion that both methods should be applied as complementary tests for the efficient selection of highly resistant potato clones. For inoculations, two isolates of PLRV were applied, and one of them, isolate L7, was routinely used in screening breeding materials for resistance to the virus. The second isolate originated from plants of the highly resistant clone DW84-1457, which were incidentally infected with PLRV. The virus isolated from these plants was able to infect only specific clones, which were resistant to isolate L7. At the same time, potato clones with resistance derived from a source different from that present in DW84-1457, and standard susceptible and resistant cultivars, showed generally lower infection ratings after inoculation with the new isolate. This result suggests that the isolates may be different strains of PLRV. It is possible that under the strong selection pressure of resistance genes present in clone DW84-1457, a new isolate I-1457 could evolve the ability to overcome resistance to infection controlled by these genes.     

One cell: The thin slice of profit

Calculations based on average parenchyma cell diameters of 160 to 240 μ in potatoes show that for chips expected losses range from 8 to 12% at 2 mm slice thickness, and from 16 to 24% at 1 mm thickness. Similar calculations for different size and thickness of dice used in dehydrated and frozen potato products show losses ranging from 4 to over 13% per piece. These calculated losses are due entirely to cut cells, the contents of which are washed out before processing. It is assumed that clean, sharp cuts are made without tearing of additional cells. These calculations do not take into account losses from peeling, trimming, leaching, irregular pieces, and other sources. Total losses from all potato processing may exceed 750 million pounds of potato solids per year. Relationships of these losses to the economy of potato processing and particularly to potato breeding, growing, and problems of waste reclamation and utilization are discussed.     

Relationship Between Tuber Storage Proteins and Tuber Powdery Scab Resistance in Potato

The potato genotypes (Solanum tuberosum L.) with russet tuber skin are generally resistant to powdery scab (Spongospora subterranea f.sp. subterranea or Sss). Lipoxygenase (LOX; EC 1.13.11.12) and patatin are two key storage proteins that are known to offer resistance to several diseases and insects. The objective of this study was to find out the relationship of these proteins in stored tubers with potato tuber powdery scab resistance, especially in russet skinned potatoes. An evaluation of potato germplasm with different tuber characteristics in a greenhouse environment over several years (2006–’11) suggests that russet skinned tuber genotypes (Mesa Russet, Centennial Russet and Russet Nugget) with negligible tuber disease severity index (DSI) and 100 % marketability were resistant to powdery scab. Higher physiological levels of LOX protein (on a dry weight basis) were negatively correlated with tuber DSI and positively correlated with tuber russet skin. Tuber total protein and patatin-lipase levels did not have a significant relationship with tuber powdery scab resistance. The proposed role of LOX protein in suberin- and/or non-suberin-mediated mechanisms of powdery scab resistance in russet skinned tubers are discussed here. The physiological levels of LOX protein can be considered as a useful marker for powdery scab resistance in potato breeding programs.     

Colorado potato beetle resistance management strategies for transgenic potatoes

NewLeaf potatoes could provide substantial ecological and economic benefits to potato growers. A concern with NewLeaf potatoes, however, is that Colorado potato beetle may develop resistance to the Bt endotoxin because of the intense selection pressure imposed by its constant presence in the transgenic crop. Before these cultivars were released, however, entomologists throughout North America conducted biological research needed for a strategy to prevent or delay resistance in Colorado potato beetle. This paper describes the considerations and research behind the proposed strategy. Because NewLeaf potatoes express a relatively constant and high concentration of Bt endotoxin throughout the foliage of each plant, reducing selection for resistance must come from planting standard potatoes as a refuge for susceptible beetles. Avoiding resistance through random mixtures of NewLeaf and standard potatoes was evaluated in laboratory and field studies. The conclusion from this research was that the seed mixture would not provide an effective refuge. The most effective alternative refuge was judged to be a block of standard potatoes planted in the same field as the NewLeaf potatoes. By allowing susceptible beetles to survive in their fields, potato growers might sustain the benefits of very effective controls.     

Populations of aphids on named varieties of Irish potatoes

Populations of the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas), were observed on 27 named varieties of Irish potatoes in the Yakima Valley of Washington intermittently from 1947 through 1968. The Epicure, Great Scot, and B5141-6 varieties produced relatively fewer green peach aphids than other varieties tested; Bliss Triumph and Red Pontiac produced relatively fewer potato aphids. Except for Doebay Red, the red-skinned varieties, Bliss Triumph, Red McLure, Norland, and Earnly Rose, were extremely to moderately productive of the green peach aphid. No correlation was apparent between abundance of aphids and the specific gravity or yield of tubers.     

The effect of theH1 gene in potatoes,conferring resistance toGlobodera rostochiensis,on resistance toG. pallida derived fromSolanum vernei andS. tuberosum ssp.andigena CPC 2802

Summary The major geneH1 confers resistance in potatoes to the golden potato cyst nematode (Globodera rostochiensis). No direct effect of the gene on resistance to the white potato cyst nematode (G. pallida) was found, but factors increasing resistance toG. pallida were detected and it is possible that these are linked to theH1 gene. The implications of such linkage are discussed.     

Progress and Successes of the Specialty Crop Research Initiative on Acrylamide Reduction in Processed Potato Products

Acrylamide, a suspected human carcinogen, is a Maillard reaction product that forms when carbohydrate-rich foods are cooked at high temperatures. Processed potato products, including French fries and potato chips, make a substantial contribution to total dietary acrylamide. Health safety concerns raised by acrylamide in food increased financial risks to the potato industry and encouraged industry to take a proactive approach toward acrylamide mitigation. The USDA National Institutes of Food and Agriculture Specialty Crop Research Initiative (SCRI) on acrylamide reduction in potato was a cooperative endeavor in which industry partners worked at a systems level with university and government researchers to develop acrylamide mitigation strategies. Short-term goals focused on identifying advanced breeding clones and recently released varieties that have lower acrylamide-forming potential than standard potato varieties. Research was also directed at developing more efficient potato breeding methods, including marker-assisted breeding, genome wide selection, and improved phenotyping methods. Data from the National Fry Processing Trial (NFPT) and SCRI agronomic trial have shown that dramatic reductions in acrylamide are achievable through the use of new varieties that maintain low concentrations of tuber reducing sugars. Chipping potato trials coordinated by Potatoes USA and data from breeding populations suggest that maintaining low tuber reducing sugars through extended storage and lowering tuber asparagine content are options for decreasing acrylamide content in potato chips. To have an impact, new varieties must have exceptional agronomic performance and must produce finished products that meet requirements for consumer attributes including color, texture and taste. Data consistently show that this is more easily achievable in chipping potatoes than in fry processing potatoes.     

Evaluation in pot and field trials of resistance of potato cultivars and breeding lines to common scab caused byStreptomyces scabies

Summary The resistance to common scab of nine cultivars and eight advanced breeding lines of potatoes, fiveSolanum andigenum Juz. et Buk. clones, and three potato breeding lines selected for resistance to common scab, was investigated in a field and a pot trial. In the pot trial potaroes were planted in inoculated coarse river sand in plastic pots (150 mm in diameter) placed on irrigated subsoil in a glassfibre house. In a field trial potatoes were planted in an artificially infested field. The harvested tubers were scored individually for scab incidence according to two scales, viz. a 1–5 point scale for percentage surface covered with scab and a 1–3 point scale for lesion type. A scab index value was calculated for each tuber. A significant correlation coefficient of 0.82 was obtained for the results of the two tests.     

甘肃省马铃薯产业现状及提升措施建议

本文在对甘肃省马铃薯产业现状进行简要阐述后,认为甘肃马铃薯产业涉及的品种选育、种薯繁育、商品生产、贮藏保鲜、加工转化、市场销售等6大环节已发展完备,但发展不平衡,不配套,产业链没有形成有效对接,整个产业大而不强,缺乏产业整体的市场竞争力。产业各环节自身还存在大大小小的问题亟待解决。通过对存在问题的原因进行深刻分析后,进而提出了"设立育种专项"等进一步提升甘肃省马铃薯产业特色优势的措施建议12条。     

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。     

A case history: Hundred years of potato production in Europe with special reference to the Netherlands

The production of potatoes has become important in Europe, especially since the 19th century. Since 1850 the yield of ware potatoes increased in The Netherlands from approximately 10 t ha^?1 to the present level of 45 t ha^?1. This was achieved by various improvements in production techniques. Several breakthroughs were accomplished in breeding for host resistance against pathogens. The current use of pesticides (nematicides, herbicides, fungicides, etc.) is high in potato production, at least in The Netherlands, particularly due to the use of fumigants to control nematodes in the starch potato growing areas. The Dutch government adopted objectives with respect to general reductions in the use of pesticides and the leaching of nutrients (nitrate). Adaptations in cultural measures are required to meet these objectives and to arrive at more sustainable systems of production in the future. In this paper special attention is given to past and present problems and possibilities with respect to cyst nematodes, late blight, wart, Colorado potato beetle, nitrogen nutrition, weed control, haulm destruction and sprout suppression.     

彩色马铃薯在恩施州的引种栽培试验

将2009年引进的彩色马铃薯品系在温室扩繁后进行正规的栽培试验,对各品系的生育期、植株及块茎的形态特征、晚疫病抗性、产量等综合性状进行分析,从中选出优良品系,为恩施州彩色马铃薯育种和下一年的正规试验提供材料和科学的依据。结果表明:AC0338和AC0151两份品系综合性状较优,有望成为恩施州彩色马铃薯主推新品种。     

The Effect of Long Term Storage on Bacterial Soft Rot Resistance in Potato

Bacterial soft rot is a serious disease in potato (Solanum tuberosum L.), causing rapid tuber tissue maceration and, consequently, marketable yield loss. Soft rot bacteria, including Pectobacterium carotovorum subsp. carotovorum (Pbc), are favored by moist conditions, which are prevalent in large potato storage facilities. However, although most potatoes in North America are stored before use, there are no published surveys of soft rot resistance in cultivars exposed to long-term storage conditions. Thus, we tested 65 cultivars and 13 breeding lines for soft rot resistance after 6 months of storage. There was a significant effect of cultivar and production environment on soft rot resistance score. During 6 months of storage, tuber soft rot resistance in resistant clones did not change, while it changed in susceptible clones. The three most resistant cultivars to soft rot were Freedom Russet, Anett, and Alaska Red Eye.