Alaska red: A general purpose,productive, red-skinned potato

‘Alaska Red’ is the first red-skinned potato bred and selected in Alaska as a clone suitable for the fresh potato market. Its parents are Alaska Clone 11-57-1-59 and ‘Red Beauty’. It is a high yielding, medium specific gravity potato with uniform skin and eye basin color, shallow eyes, uniform oval-to-flattened shape and is very attractive. The flesh is snowy white and remains white after boiling. Alaska Red keeps well in storage at 38°F (3.3°C). Scab of the tubers is the only disease that has been observed. In this subarctic region, flowers abort in the early bud stage. Red-skinned potato varieties available to Alaskan growers for the past quarter century have been unsatisfactory due to one or more of the following characteristics: low dry matter content, poor yield, uneven skin pigmentation and internal or external tuber cracking. Although consumers buy far less red than white-skinned potatoes, the demand brings Florida “reds” to Alaska as well as “reds” from other regions so that there is a year round outlet. Imported “reds” never approach the high quality of Alaskan grown “reds”. During the screening of seedlings, ‘Red Beauty’ was selected as a parental line because of its excellent conformation, skin color and eye arrangement. Low yield and shatter cracking made it unsuitable for commercial production. Alaska Red is a selection from seedlings of the cross Ak. 11-57-1-59 and Red Beauty made in 1965 and is the first red-skinned potato released from Alaska’s potato breeding. It was first evaluated by potato growers in 1972 and released in 1976 by the Agricultural Research Service, United States Department of Agriculture, Box AE, Palmer, Alaska 99645.     

Losses during Storage of Potato Varieties in Relation to Weather Conditions during the Vegetation Period and Temperatures during Long-Term Storage

Degradation of harvested tubers due to water loss, sprouting, and disease can cause severe economic difficulties in the cultivation of potatoes (Solanum tuberosum). This study evaluated the storage losses of new varieties of potato and determined the sprouting dates of potatoes stored at different temperatures. Additionally, this study evaluated the influence of weather conditions during the vegetative growth period on the date of sprouting in storage. After storage at three different temperatures (3, 5, and 8 °C), we estimated natural losses and losses caused by sprouting or the development of disease. The potato varieties stored at 3 °C, and 5 °C had similar weight losses (8.8% and 9.3%, respectively), but the potatoes stored at 8 °C had higher losses (10.8%). The average potato losses caused by disease ranged from 0.6% to 10%. The onset of sprouting of potatoes stored at 8 °C depended on the variety and began in the 20 day of December. Storage at 5 °C delayed sprouting by about 50 days compared with storage at 8 °C. Weather conditions (hot and rainy) during vegetative growth of the plants also influenced sprouting date, natural losses, and the amount of disease during storage. Our data showed a significant correlation between the hydrothermal coefficient during the vegetative period and the date of sprouting of potatoes during storage.     

Elkton: A New Potato Variety with Resistance to Internal Heat Necrosis and Hollow Heart and Suitable for Chipping Directly from the Field in the Southern United States

Elkton is a medium to medium-late maturing potato variety with tan netted-skin, round-oval tubers, and white-flesh. Average marketable yields ranged from 76 % to 113 % of Atlantic and average specific gravities ranged from ?0.002 to ?0.006 less than Atlantic depending on location. Chip color processed directly from the field in southern locations or from storage in the northern locations is equivalent to Atlantic. Elkton is resistant to internal heat necrosis and hollow heart. Color and texture ratings of Elkton following baking, boiling and microwaving have been similar to Atlantic. Elkton is moderately resistant to early blight and Verticillium wilt; moderately susceptible to foliar late blight and susceptible to tuber late blight; moderately susceptible to powdery scab; and, susceptible to potato virus Y and potato virus S. Its reaction to common scab has been inconsistent. Plant Variety Protection has been requested for Elkton.     

Evaluation of “UFV Aeroponic System” to Produce Basic Potato Seed Minitubers

We evaluated misting nozzle types and the coating on the bucket’s inner wall on the yield of basic potato seed minitubers. Tubers of potato cv. Agata were sprouted in a non-acclimatized greenhouse from June to September 2013. Six treatments were evaluated, three types of misting nozzle (32 L/h with anti-drip, 32 L/h without anti-drip, and 9 L/h without anti-drip) and two types of bucket inner lining, with and without polyurethane, with four replications. Dry weight of roots, stems and leaves besides minituber number and tuber fresh weight were evaluated. The “UFV Aeroponic System” effectively produces minitubers and should be equipped with a fogger with an outflow of 32 L/h without anti-drip and no inner lining of the bucket for optimal yield.     

Sugar-Starch Metabolism and Antioxidant Potential in Potato Tubers in Response to Different Antisprouting Agents During Storage

Single applications of different antisprouting agents like hot water treatment, spearmint oil and clove oil were carried out on potato cultivar “Lady Rosetta” to compare their efficacy with that of synthetic chloro isopropyl N-phenyl carbamate (CIPC). The tubers were stored at ambient storage conditions (25?±?2 °C) for 81 days to assess changes in their sugar-starch concentrations and antioxidant potential. Antioxidant potential in the tubers was assessed as their total phenolic concentrations and radical scavenging activities. In addition, the enzymatic activities were also determined in order to evaluate the possible depletion of these antioxidants as substrate during storage. Results revealed significant response of stored potatoes to all antisprouting agents compared with the control (P?≤?0.05). CIPC and clove oil applications maintained tuber dormancy almost twice as long (81 days) as observed in the control (45 days). Application of spearmint oil and hot water treatment maintained tuber dormancy for almost 2 months. However, it was associated with an increased percentage sprouting during the last weeks of storage. At the end of storage, the highest starch (16.83%) and lowest sugar (0.99%) concentrations were estimated after CIPC application and maximum total phenolic concentration (143.57 mg gallic acid equivalent (GAE)/100 g), and highest antioxidant activity (39.73%) were found after clove oil application. Enzymatic activities were not statistically different between CIPC and clove oil application during most of the storage period. Results showed that efficient replacement of CIPC with clove oil in the premium potato cultivar might be useful; this may avert related food safety and environmental issues and would also ensure organic potato storage.     

Varietal Differences in Minituber Production Costs

Minitubers have become important components of seed potato production systems. Minituber production methods and yields affect costs. We used data from the University of Wisconsin seed potato program to estimate minituber production costs by variety in 2009, 2010, and 2011. Labor is identified as the most significant operating cost, while salaries represent the greatest fixed cost. The 3 year average total cost per minituber across all varieties was estimated at $0.47. Of the varieties grown in all 3 years of analysis Langlade had the highest average yield and lowest cost. Yukon Gold and Pike had the lowest yields and highest costs.     

Pomerelle Russet: an Early Maturing Potato Variety with High Yields of U.S. No. 1 Tubers Suitable for Fresh Market and mid-Storage Processing and Tolerance to Potato Mop-top Virus

Pomerelle Russet is an early maturing fresh potato variety, which produces moderately high early-season (95–110 days after planting) yields of long tubers with brown-russet skin. It is notable for its very attractive, smooth tubers and resistances to internal and external defects with a high percentage of U.S. No. 1 tubers. Fresh merit ratings for Pomerelle Russet in trials conducted in Idaho, Oregon and Washington were consistently higher than Russet Burbank and Russet Norkotah. Early harvest yields for Pomerelle Russet are generally comparable to Russet Norkotah with a higher percentage of U.S. No. 1 tubers. Compared to Russet Burbank and Russet Norkotah, Pomerelle Russet has greater resistance to Potato mop-top virus, soft rot, corky ringspot and tuber infections from late blight. It also has higher protein and vitamin C concentrations than Ranger Russet, Russet Burbank and Russet Norkotah, indicating that it can provide an enhanced level of dietary protein and vitamin C relative to these standard potato varieties. Pomerelle Russet has moderate specific gravity and good resistance to sugar ends. It also has moderately long dormancy, about 30 days shorter than Russet Burbank. Average post-harvest processing ratings for Pomerelle Russet were similar to Ranger Russet and greater than Russet Burbank. Pomerelle Russet also has maintained acceptable fry color for about 180–200 days in storage at 8.9 °C, indicating potential for processing out of mid-term storage, with improved fry color uniformity relative to industry standards. However, its primary use appears to be as a high quality, early fresh variety.     

Change in Some Glycoalkaloids of Potato under Different Storage Regimes

The potato (Solanum tuberosum L.) is an important food crop worldwide. Potato tubers can be stored to provide continuity of supply between production seasons, but it is important that they be stored under appropriate conditions as incorrect storage will result in deterioration in end user quality and may increase glycoalkaloid levels. We have investigated the effects of types of household storage on potato glycoalkaloid content (total glycoalkaloids [TGA]; α-solanine; α-chaconine) in Turkey. Tubers of potato cultivars (cvs.) Agria and Bettina were stored under four types of storage conditions (indirect sunlight for 10 h per day and dark storage for the remaining 14 h per day; storage under continuous fluorescent light; storage in constant darkness; storage in the dark in a refrigerator) for 56 days. Samples of tubers were taken at the beginning of the storage period and after 14, 28 and 56 days of storage for tuber glycoalkaloid measurement. Tubers stored in the three light environments showed an increase in glycoalkaloid levels; however, none of the cv. Agria tubers reached the critical level of 200 mg/kg tuber. On day 56 the TGA level of cv. Bettina tubers stored under fluorescent light reached 234.31 mg/kg.     

Screening for Chip-Processing Potato Line from Introgression of Wild Species’ Germplasms with Post-Harvest Storage and Chip Qualities

The processing of potatoes into chips is expanding in China. There is a need for new processing cultivars that are well-suited for the local ecological environment. Eleven potato varieties were bred from hybridization and backcrossing between the local cultivated potato varieties (Solanum tuberosum L.) and wild potato species. Lines from different wild species’ germplasms showed that the ability to accumulate reducing sugars was significantly different during low temperature storage (4 °C). A correlation analysis was conducted to determine the correlation coefficient among reducing sugars, acid invertase, free amino acids, chip colors and the content of acrylamide after storage at room and low temperatures. The lines 0706-116, 0737-6 and 0726-205 had low levels of reducing sugars, acrylamide content and acceptable chip colors for potato chip processing. The results indicated that the transfer of wild species’ processing traits into local cultivars by hybridization and continuous backcrossing is an effective potato breeding method and that the wild germplasm resources S. phureja and S. chacoense are suitable for improving the processing traits of local varieties.     

Somerset: A new chipping potato variety

The Somerset potato variety is a medium-maturing variety with attractive, round to oblong, white-skinned, white-fleshed tubers with shallow eyes. Its major use is expected to be as a chipping variety in areas where potatoes are stored for some length of time, since its sugar content is lower than most varieties during storage, and it can be chipped after six months in storage. Somerset does not show the net necrosis caused by potato leafroll virus, and is immune to race 0 of Phytophthora infestans (late blight). Somerset is also moderately resistant to infection by Alternaria solani (early blight), and is only moderately susceptible to Verticillium wilt. Somerset is more susceptible to both common and acid scab than Superior, but less susceptible than Kennebec and Katahdin. It also has shown susceptibility to skinning and shatter bruise, but does not have a strong blackspot bruise reaction.     

Rate of Cooling Alters Chip Color,Sugar Contents,and Gene Expression Profiles in Stored Potato Tubers

When stored at temperatures below 10 °C, potatoes accumulate sucrose and the reducing sugars glucose and fructose. This process, cold-induced sweetening, has been studied extensively because potatoes with elevated reducing sugar contents produce undesirable, dark-colored products and acrylamide, a suspected carcinogen, during high-temperature cooking. Potatoes in commercial storages are cooled slowly, but many research studies have used potatoes cooled rapidly. In this study, effects of cooling rate and variety on chip color, sugars, and gene expression were examined. Sucrose and reducing sugar contents were substantially lower in slowly cooled than in rapidly cooled tubers of ‘Snowden’ and “MegaChip’ for the first 11 weeks after cooling to 3 °C began. Differences in gene expression for VInv, β-amylase, SPS, AGPase and GBSS were observed between cooling treatments and varieties. Overall, the data showed that cooling rate, time in storage, and variety influenced multiple aspects of cold-induced sweetening.     

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.     

Characterization of the Tolerance against Zebra Chip Disease in Tubers of Advanced Potato Lines from Mexico

Potato zebra chip disease (ZC), a threat to potato production in the USA, Mexico, New Zealand, and Central America, is associated with the bacterium “Candidatus Liberibacter solanacearum” (Cls) that is vectored by the potato psyllid (Bactericera cockerelli Sulc.). ZC control currently depends on insecticide applications, but sustainable control will require development of resistant and/or tolerant varieties. This study characterized four promising potato lines (246, 865, 510 and NAU) exposed to Cls-positive adult psyllids in choice and no-choice assays for ZC resistance. Psyllids preferred to settle on Atlantic over 246 and 865, and oviposit on Atlantic compared to 510. However, tolerance to ZC appeared more dependent on host responses to Cls infection. All four of these potato genotypes exhibited putative ZC tolerance in raw tubers compared to the susceptible commercial variety Atlantic. Expressed tolerance was associated with reduced concentrations of phenolic compounds in Cls-infected raw tubers with corresponding reductions in freshly-cut symptoms. However, these four genotypes exhibited ZC-linked discoloration of fried tuber slices, which was associated with increased sugar content that occurred following Cls-infection. As a result, these four ZC-tolerant experimental potato lines could be useful if the tubers produced are used for fresh, but not processing, markets.     

Effect of culture,storage and variety on polyphenol oxidase and peroxidase activities in potatoes

The Viking potato variety was found to possess the highest activities for polyphenol oxidase and peroxidase, among the five varieties tested. The Norland and Pontiac varieties possessed the lowest polyphenol oxidase activity. There was a direct positive correlation between storage temperature and peroxidase activity (r = 0.66). The application of fertilizer potassium was shown to be a significant factor determining polyphenol oxidase activity in the tubers (p = 0.025), appearing in interactions with storage temperature and variety.     

Potato chip color,specific gravity and fertilization of potatoes with N−P−K

The effects of fertilizers on potato chip color were studied over a period of 11 years. Yield and specific gravity data also were taken. Single element and compete fertilizers were used in randomized block and split plot experiments. Most of the work was done with the Russet Burbank variety but in some experiments the Kennebec, White Rose, Norgold Russet and Cascade varieties were also included. Specific gravity and chip color data were taken immediately after harvest. Effects of storage and reconditioning on chip color were recorded in some cases. Though statistically significant effects of N?P?K on chip color were found, the differences were small and of no commercial importance. Neither nutrient balance nor total amount of fertilizer used greatly affected chip color whether the tubers were harvested “immature” in July or in October after the vines were dead. The greatest effect of over-fertilization was on the specific gravity of the tubers. As amount of fertilizer applied increased, specific gravity often decreased which would reduce the amount of processed product per unit of fresh produce. Since most manufacturers of processed potatoes prefer high specific gravity tubers perhaps varieties should be grown specifically for the processing industry. Since proper fertilization did not have a commercially important effect on chip color but greatly increased the yield, farmers should fertilize for maximum production when growing potatoes for potato chips.     

Sensory Evaluation of Eleven Baked Russet-type Potato Varieties and Clones

Six hundred untrained panelists evaluated the baked sensory appeal of up to six varieties, three clones, and two Russet Norkotah (RN) strains. Panelists consumed small samples of plain baked potato and recorded their preference for aroma, flavor, texture, aftertaste and acceptance. After viewing photographs of two unidentified baked potatoes (RN and Classic Russet) sliced in half, they selected the photo that best described their visual preference of a baked potato; each potato was stored at 6.7 °C for 6 months prior to cooking. Eighty percent of panelists shown the photographs of the unidentified baked potatoes preferred the visual appearance of Classic R (white/cream - colored  flesh) to that of RN (yellow/Gy - colored flesh). Mean scores for all culinary traits averaged > 5.0 on the 1-9 scale, which indicated that panelists generally liked the culinary attributes of all trialed varieties, however, panelists were able to detect differences among varieties. Flavor and texture were addressed in written comments from panelists more frequently than other attributes. On a texture scale of 1–7, with 1 = moist/dense and 7 = dry/crumbly, most panelists preferred baked potatoes with a texture of 3 (creamy/smooth).     

Variability of Phytonutrient Content of Potato in Relation to Growing Location and Cooking Method

Potato has a defined complement of metabolites that contribute to the human diet. Among these are the carotenoids and anthocyanins. Carotenoids are found in all potatoes in the flesh. White-fleshed varieties have 50 to 100 μg per 100 g fresh weight (FW), while moderately yellow-fleshed varieties will generally possess from 100 to 350 μg per 100 g FW. The more intensely yellow-fleshed genotypes, which may look orange, at the higher extremes are at levels above 1,000 μg per 100 g FW. The highest level published is 2,600 μg per 100 g FW in diploid germplasm derived from South American Papa Amarilla cultivars. Potato generally has predominantly lutein, a xanthophyll which is also found in the human retina, and must be obtained in the diet. The genotypes with extremely high levels of total carotenoids have zeaxanthin, an isomer of lutein, which is also present in the human retina. Anthocyanins are present in red- or purple-skinned and fleshed varieties. Total anthocyanins range from 1.5 mg to 48 mg per 100 g FW in a solidly pigmented purple-skinned, purple-fleshed breeding line. The degree of pigmentation in the flesh appears to be under polygenic control. Anthocyanins are potent antioxidants and anti-inflammatory substances. The level of total anthocyanins is correlated with antioxidant level (r?=?0.94, P?<?0.001). Several methods of cooking interacted with genotypes in the antioxidant level remaining after cooking compared to raw potatoes. No method of cooking completely eliminated antioxidant activity, while boiling appeared to increase it compared to raw potato in the case of the most highly pigmented clone.     

Potentiality of Potato Flour as Humectants (Anti-staling Agent) in Bakery Product: Muffin

The potential of potato flour as a humectant (anti-staling agent) was investigated. The experiment utilised eight variants of potato flour, prepared from processing cultivar K. Chipsona-1 and table cultivar K. Laukar, in muffins as a bakery product. On the basis of higher values of water retention and water absorption, and comparatively lower values of setback and flavour intensity, grilled (180 W for 25 min) potato flour from cultivar K. Laukar (GPF-T) was selected for muffin preparation. For optimization, muffins were prepared with GPF-T at 1, 3, 5 and 7% (w/w) level in the formulation. The storage study was conducted for 8 days at 25?±?2 °C and 55?±?5% RH. It was concluded from the product characterisation, sensory evaluation and storage study that 3% GPF-T can be used as a low-cost alternative to commercially available humectants for muffin preparation. Research findings may be adopted by small-scale industry entrepreneurs to delay the staling of muffins two-fold without adversely affecting the sensory scores.     

Determination of Glycoalkaloids in Potatoes and Potato Products by Microwave Assisted Extraction

Potato glycoalkaloids can reach levels that are harmful to human health. A rapid and reliable microwave assisted extraction method for quantitative analysis of α-solanine and α-chaconine content in raw potato and potato based products is presented. A chemical microwave was used to determine optimal temperature and pressure conditions for the extraction of α-solanine and α-chaconine from Idaho grown tubers and six commercially available mashed potato products. Recovery efficiency of glycoalkaloids was 37% greater by microwave assisted extraction (19.92 mg/kg glycoalkaloid) as compared to conventional solid/liquid methods (12.51 mg/kg glycoalkaloid). Optimal extraction of glycoalkaloids from potato samples dissolved in methanol was achieved using a microwave reactor set to 90 °C for ten minutes. The interior of Idaho grown tubers was determined to contain lower levels of glycoalkaloids (19.92 mg/kg dry weight; 6.5 ± 1.78 mg α-solanine and 13.40 ± 1.65 mg α-chaconine), as compared to commercial potato products (33.86–81.59 mg/kg).     

Potato Breeding: a Challenge, as ever!

Breeding efforts for the potato sector are faced with the classical questions “What to breed?” and “How to breed?”. The answers to these questions are very diverse and challenged. Until recently these two questions were unrelated. With the increase in scientific knowledge and the public debate on modern tools, these questions have become intertwined. The “What to breed?” question has changed: breeders nowadays have to breed for wider adaptation to increasingly stressful environments with an increase in focus on quality demands by an increasingly complex and diverse food processing industry and distribution networks. The “How to breed?” question has changed also: public funding is increasingly scarce for agricultural research in general and for research on the biotechnology, molecular genetics and molecular biology of potato in particular. Young scientists also move away from the potato crop. However, the complexity of the inheritance and of the physiology of potato combined with the diverse stress to which this crop is exposed, requires large investments to be able to use modern scientific tools. Such huge investments are mostly too costly for the traditional dominant players in potato breeding despite the mergers that have taken place. The only solution for this is to link up with and stimulate international networks and use the modern information technology to obtain access to valuable scientific information. The technology used also determines public acceptance of the product, thus making the “What to breed?” and “How to breed?” questions interwoven. Another important issue that has affected the environment for potato breeders is the fact that breeders have not been defending their rights very well. Counterfeited multiplication of protected varieties has become commercially more important whereas new conventions and treaties have made the exchange and use of germplasm much more complicated. Modern potato breeders, while maintaining their classical skills, have to be prepared to be more involved in basic science, more receptive to public concerns and more proactive to protect their rights.