Potato Processing for the Consumer: Developments and Future Challenges

In merely half a century industrial processing of potatoes into consumer products has developed into a major activity in the potato world. Yearly about 30 million MT of potatoes or almost 10% of the global potato crop are converted into consumer products, mainly in the EU and North America where one to two thirds of the daily potato consumption is in a processed form such as French fries and potato chips. In the first part of this paper the developments in potato processing are described: the global growth of the processing industry, the development of consumption and market, product diversification, and developments in potatoes supply for processing. The second part is devoted to the future challenges of global development, consumption, health and new product development, sustainability, and new cultivar development.     

Challenges to Organic Potato Farming: Disease and Nutrient Management

For organic potato producers the two main challenges are disease and nutrient management. Both factors are limited by regulations that on the one hand prohibit the use of chemical fertilisers, especially nitrogen and, on the other hand, most synthetic pesticides. Late blight, caused by Phytophthora infestans is commonly thought to be the factor most limiting yield. However, because there is no really effective fungicide available to control late blight, there are virtually no yield loss data available for organic farming conditions. In this paper the state of the art of organic potato management with respect to disease and nutrient management is summarised. In a second part, the interactive effects of N-availability in the soil, climatic conditions and late blight were studied in the presence and absence of copper fungicides from 2002–2004 for the mid-early main-crop potato cv. Nicola. From the experimental work it became clear that copper fungicides in most cases do slow down epidemics adding an average of 3 days to the growth duration. However, only 30% of the variation in yield could be attributed to disease reduction. A model including disease reduction, growth duration and temperature sum from planting until 60% disease severity was reached, and soil mineral N contents at 10 days after emergence could explain 75% of the observed variation in yield. However, the model failed when N-supply was extremely high. The implications of the results on the management of organic potatoes with respect to cultivar choice, nutrient and disease management are discussed. In conclusion, several points emerge from the results: In organic farming, yields are foremost limited by nutrient availability in spring and early summer. The effects of late blight on yields may often be overestimated and cannot be deducted from results in conventional farming because of the strong interaction with nutrient status. Resistance clearly remains the most important strategy against late blight in organic potato production. However, as important or even more important than resistance is the early development and bulking behaviour and the ability of a cultivar to make use of organic nutrients efficiently. In the absence of efficient organic pesticides it is possible to reduce blight pressure to a certain extent by arranging the crop in small narrow fields perpendicular to the main wind direction neighboured either by non-hosts or completely resistant potatoes.     

Improving Potato Tuber Quality and Production by Targeted Calcium Nutrition: the Discovery of Tuber Roots Leading to a New Concept in Potato Nutrition

Calcium plays a major role in plant growth and development and in the maintenance and modulation of various cell functions, especially related to membrane structure and function and to cell wall structure. Calcium stabilizes cell membranes by bridging polar head groups of phospholipids at the membrane surface. Calcium is also an integral part of the cell wall where it provides stable intra-molecular linkages between pectin molecules, resulting in cell wall rigidity. A change in the cytosolic calcium concentration is also known to provide a cellular signal that regulates metabolism and mediates plant responses to stresses.     

The Effect of Nitrogen Rate on Vine Kill,Tuber Skinning Injury,Tuber Yield and Size Distribution,and Tuber Nutrients and Phytonutrients in Two Potato Cultivars Grown for Early Potato Production

Early potatoes are typically produced using less nitrogen than a full season potato crop as high rates of nitrogen may delay tuber set and lead to excessive vine growth that is difficult to terminate prior to harvest. Bintje and Ciklamen potato cultivars were grown with preplant soil nitrogen levels of 34 to 38, 67, and 101 kg N ha^-1 in 2013 and 2014 near Paterson, Washington. Nitrogen rate had little impact on the number of tubers and stems per plant of both cultivars, but increasing nitrogen rate tended to increase leaf area of both cultivars. Vine desiccation of Bintje with diquat was less complete as nitrogen rate increased, while Ciklamen vine kill was reduced by higher nitrogen in 1 of 2 years. Tuber skinning injury, tuber weight loss, and tuber size distribution were not affected by nitrogen rate. Tuber skinning injury and tuber weight loss were reduced in both cultivars by harvesting at 4 weeks after initial vine kill compared to harvesting at 2 weeks after vine kill. Total tuber yield was lower for both Bintje and Ciklamen in 1 of 2 years at the 34 to 38 kg N ha^-1 rate. Tuber nitrogen and zinc levels tended to increase with increasing nitrogen rates, while most other nutrients, vitamin C, total phenolics, and antioxidant capacity showed little response. It appears that 67 kg N ha^-1 provides adequate nitrogen to produce a good tuber set and yield of small tubers while not producing excessive vine growth that may be more difficult to kill.     

The Effect of Vine Kill Method on Vine Kill,Tuber Skinning Injury,Tuber Yield and Size Distribution,and Tuber Nutrients and Phytonutrients in Two Potato Cultivars Grown for Early Potato Production

Sixteen vine kill programs were tested on Bintje and Ciklamen potato cultivars grown for early potato production over a three year period near Paterson, Washington. Mechanical (flail chopping, flail chopping and undercutting), chemical (glufosinate, diquat, sulfuric acid, carfentrazone, pyraflufen-ethyl), and physical (flaming) vine kill methods, and sequential combinations of the three were effective in killing rapidly growing potato vines of Bintje and Ciklamen. Rolling and crimping did not kill vines as completely and more vine regrowth occurred than with most other methods tested. Tuber skinning injury was greatly reduced when harvesting at 4 weeks after initial vine kill than at 2 weeks. None of the vine kill programs were able to hasten skin set enough to allow tubers to be harvested at 2 weeks after initial vine kill without significant tuber skinning injury. Glufosinate treatments that were applied several days earlier than other initial vine kill treatments tended to average less skinning injury at the early harvest possibly due to more time elapsing between initial vine kill and harvest. Total tuber yield and size distribution were similar among most vine kill treatments, with the exception of the earlier applied glufosinate treatments, which tended to reduce total yield, but still yielded a similar mass of desired 25 to 35 mm diameter tubers. Tubers from vine-killed plots tended to average greater N, P, K, Fe, and Ca content than tubers from non-killed control plots of both cultivars. Tuber ascorbate levels were also greater in non-killed controls, whereas total phenolic content tended to be greatest in earlier-applied glufosinate treatments. Nonchemical vine kill methods, chemical vine kill methods, and combinations of the two were identified that killed vines well, had low skinning injury at the 4 week harvest, and yielded similar amounts of 25 to 35 mm diameter early potato tubers.     

Potato Management Challenges Created by Phosphorus Chemistry and Plant Roots

A primary objective of phosphorus (P) management is to maintain optimal levels of P in the soil solution at the root surface. Potato plants typically have low root density, resulting in higher solution P concentration needs and critical soil test levels than most other common crop plants. The chemistry of P in fertilized soils makes maintaining these high P concentrations a challenge. Phosphorus has a very high affinity for the soil solid phase with iron (Fe) and aluminum (Al) dominating reactions in moderately acid soils and calcium (Ca) in alkaline soils. Guidelines for P stewardship for potato production are: (1) adopt practices that develop soil conditions that favor root growth and development; (2) make source, rate, time and placement decisions for nutrient applications that maintain optimal soil solution P concentrations during critical growth stages; and (3) use soil and water conservation practices to minimize P losses from the root zone and the field.     

马铃薯纺锤块茎类病毒(PSTVd)的检测与防治研究进展

详细阐述了马铃薯类病毒(PSTVd)鉴定技术的研究进展,比较了几种鉴定技术(指示植物、往返电泳、核酸斑点杂交及RT-PCR)的优缺点,并对类病毒的防治措施进行了论述。     

QTL Analysis of Tuber Dormancy and Sprouting in Potato

Tuber dormancy and sprouting are important traits in commercial potato varieties. Since wild Solanum species can contribute new alleles in breeding, we combined Solanum chacoense and S. berthaultii species in a mapping population to develop a linkage map with genome wide markers and identify quantitative trait loci (QTL) for tuber dormancy and sprouting. There was genetic variation for the evaluated traits and high correlation (0.80) between dormancy and apical dominance release. QTL for tuber dormancy and sprouting traits were mapped to the same or similar positions on chromosomes 2, 3, 5, and 7, explaining from 9.5% to 16.3% of the phenotypic variance. We identified candidate genes associated with all major phytohormone regulation in close linkage with the QTL. The QTL on chromosomes 2, 3 and 7 are good candidates for marker assisted breeding, since they were associated with dormancy and apical dominance release and should be useful to delay or accelerate tuber sprouting.     

原原种的块茎大小对马铃薯的农艺性状、繁殖系数和产量的影响

选用早熟品种‘荷兰15号’和中晚熟品种‘克新13号’的脱毒原原种为试验材料,分别探讨原原种块茎大小对马铃薯的农艺性状、繁殖系数和产量性状的影响。研究结果表明：‘荷兰15号’原原种,株高对种薯总产的直接作用最大;‘克新13号’原原种,保苗率和株高对种薯总产的直接作用最大。‘荷兰15号’原原种的块茎大小在10－20 g时,繁殖系数最高,原原种的块茎大小在5－20 g时,其种薯的商品薯产量和总产最高。‘克新13号’原原种的块茎大小在7－15 g时繁殖系数、商品薯产量和总产均最高。     

Potato Common Scab: a Review of the Causal Pathogens,Management Practices,Varietal Resistance Screening Methods,and Host Resistance

Potato common scab is a widespread disease in which scab-like lesions develop on tubers. The disease is caused by pathogenic Streptomyces species, which synthesize the phytotoxin thaxtomin. The txtAB operon, responsible for thaxtomin production, can be used as a marker to identify pathogenic strains of the bacterium. Screening methods to assess scab susceptibility in breeding programs are time-consuming and can produce variable results. Management practices to control the disease vary and include crop rotation, tolerant varieties, monitoring soil pH, avoiding low soil moisture at tuber initiation, and application of soil- and/or seed-applied pesticides. There is a wide range in levels of tolerance among potato varieties. Many public research programs are committed to breeding for scab-tolerant varieties and evaluating management methods. Topics reviewed target readers focused on breeding and disease management objectives to reduce the incidence and severity of potato common scab.     

Overview of the Turkish Potato Sector: Challenges, Achievements and Expectations

Having a history of nearly 150 years in Turkey, potato has become one of the most important agricultural crops of the country. Potato production, processing, marketing and consumption have become a major sector as well. However, regardless of these advancements, the Turkish potato sector has still not reached its full potential. Therefore, different approaches are needed in the Turkish potato sector to overcome chronic problems as soon as possible. This paper summarizes the past and the current situation of the Turkish potato industry and evaluates its weaknesses and strengths.     

原原种的块茎大小对马铃薯的农艺性状、繁殖系数和产量的影响

选用早熟品种‘荷兰15号’和中晚熟品种‘克新13号’的脱毒原原种为试验材料,分别探讨原原种块茎大小对马铃薯的农艺性状、繁殖系数和产量性状的影响。研究结果表明:‘荷兰15号’原原种,株高对种薯总产的直接作用最大;‘克新13号’原原种,保苗率和株高对种薯总产的直接作用最大。‘荷兰15号’原原种的块茎大小在10~20 g时,繁殖系数最高,原原种的块茎大小在5~20 g时,其种薯的商品薯产量和总产最高。‘克新13号’原原种的块茎大小在7~15 g时繁殖系数、商品薯产量和总产均最高。     

马铃薯薯形突变体T-DNA插入侧翼序列分析

以‘鄂马铃薯3号’为材料,通过试管薯快速转基因技术获得一个编号为pCL2b-2薯形突变系,本研究通过表型鉴定、侧翼序列扩增和生物信息学等方法对其进行了研究,目的是分析该突变株表型变化控制机制。结果表明,该突变体的试管薯和温室收获块茎长宽比在p<0.05水平均显著大于野生型受体薯,其中试管薯长宽比为1.78,野生型试管薯长宽比为1.33;温室收获块茎长宽比为1.50,野生型块茎为1.29;利用hiTAIL-PCR技术对T-DNA插入位点两侧的侧翼序列分析表明,T-DNA插入编码异戊烯基转移酶(IPT)基因内部,该基因为细胞分裂素合成酶基因(StIPT),暗示StIPT基因可能参与马铃薯薯形发育。     

Manipulating Stem Number, Tuber Set and Size Distribution in Specialty Potato Cultivars

Manipulating seed physiological age is an effective method to alter tuber set and size distribution for many cultivars. However, cultivars Cal White, Red La Soda, Chieftain, Yukon Gold, and Satina were largely insensitive to high temperature-induced age-priming treatments. Gibberellins (GA) also have potential for altering tuber set and size development. When applied to cut seed of the five cultivars, GA hastened plant emergence, increased stem and tuber numbers per plant, and decreased average tuber size. The optimum concentration of GA for shifting tuber size distribution to maximize crop value without decreasing total yield depended on cultivar. Total yields decreased substantially in all cultivars with 10 mg L^?1 GA but lower concentrations (0.5–4 mg L^?1) either increased yields of Red La Soda, Yukon Gold, Chieftain and Satina by 11, 13, 15, and 24 %, respectively, or had no effect (Cal White). GA-induced increases in tubers per hectare ranged from zero (Cal White, Satina) to 36 % (Chieftain) and associated increases in yields of premium priced creamer size potatoes (C size; 10–66 g, 28–51 mm diameter) ranged from 0 to 140 %, depending on cultivar and length of the growing season. Increases in total crop values ranged from 7 to 30 % (Chieftain) with the optimum concentrations of GA, which also varied by cultivar. Effective use of GA to alter tuber size distribution for increased value depends on cultivar, concentration, and harvest timing.     

Impact of Stolbur Phytoplasmas on Potato Tuber Texture and Sugar Content of Selected Potato Cultivars

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg⁻¹ fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg⁻¹ FW in 2007 and 19,560 mg kg⁻¹ FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. ‘Courage’ and ‘Lady Rosetta’ showed high numbers of diseased tubers and high sucrose concentrations, ‘Lady Claire’ had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones.     

种植密度对马铃薯品种合作88产量及大薯率的影响

以云南省高寒冷凉山区大春一季马铃薯种植的主要推广品种“合作88”为试验材料,探索不同种植密度对其产量及大薯率的影响。试验结果表明,在云南东北部马龙县土地平整、肥力上等的栽培条件下,合作88以每667m2种植1389株的密度和60cm×80cm的株行距为最佳,平均单产达到了4096.6kg/667m2,产量名列第一位,比对照(密度4167株/667m2的处理)每667m2增产鲜薯865.6kg,增产26.8%,增产极显著;大薯率达到了61.9%。     

马铃薯纺锤块茎类病毒检测技术比较与选择

马铃薯纺锤块茎类病毒(PSTVd)是威胁我国马铃薯生产的重要病害之一,目前有多种技术可应用于PSTVd的检测,如生物学方法、电子显微镜技术、往返聚丙烯酰胺凝胶电泳(R-PAGE)、核酸斑点杂交(NASH)、RT-PCR和FQ RT-PCR。这些方法各有利弊,互相补充,构成了PSTVd的检测技术体系。日常工作中,应根据自身条件及目的等科学地选择适宜的检测技术,确保脱毒种薯/种苗的质量。