整薯播种对马铃薯生育及产量的影响

1979～1984年,在黑龙江省北部黑土地区气象条件、生产水平和栽培条件下,通过田间试验,研究了整薯播种对马铃薯生育和产量的影响。结果表明:整薯播种与传统习惯的切块播种相比,6年期间平产出现频率为2次,一般年份整薯播种比切块播种增产9～12%,在春旱严重的1980年,整薯播种表现出非常突出的抗旱保苗效果。在群体叶面积发展进程上,整薯播种表现早发早衰,切块播种晚发晚表,一般年份光合势前者比后者高9.6%,春旱严重的1980年高82.8%。块茎商品率以112.5克为准时,6年平均整薯播种为74.1%,切块播种为80.0%,两者相差5.9%;以50克为准时,整薯播种为97.3%,切块播种为98.2%,两者相差0.9%。     

The effect of wound severity, type of tissue, and use of the tuber disk model system on arachidonic acid-induced rishitin accumulation in potato tuber

The wound response within damaged potato tubers (Solanum tuberosum L.) must be a coordination of suberization with other resistance responses if infection is to be avoided. Previously, we showed that wound healing was affected by wound severity and consequently the type of tissue damaged within the tuber. Using arachidonic acid-induced accumulation of rishitin as a model for phytoalexin accumulation, we now demonstrate that this tuber resistance response is also influenced by wound severity and the type of tissue exposed to the elicitor. Kennebec and Reddale tubers that were superficially wounded by removing a thin tissue slice (0.75 mm thick) from the surface and then treated with the elicitor arachidonic acid produced significantly less rishitin than more severely wounded tubers (e.g., tubers cut in half) and excised tuber tissue disks (17 mm × 4 mm). Excised, elicitortreated tuber tissues accumulated significantly more rishitin in cortical cells than in perimedullary and pith cells. Rishitin accumulation was routinely measured 96 h after wounding and was found to be declining by 144 h regardless of wound severity. Induction of rishitin accumulation was very localized with more than 80 % of the rishitin found within 0.75 mm of the treated wound. These results indicate that excised tuber tissue disks, often used as models in wound research, are not fully representative of intact tubers. Perhaps more important, the results show that superficial wounds of intact tubers, i.e., similar to shallow nick and abrasion type wounds typically incurred during harvest, accumulate very little rishitin. However, rishitin accumulation in the tuber disk model system is much greater than that found in superficially wounded tubers, but is similar to the accumulation that could be elicited in cut (seed) tubers. The complications contributed by these wound-related and tissue-specific interactions must be factored into the model system(s) used in describing the role(s) of phytoalexins in the broad framework of disease resistance for stored potatoes and cut seed.     

The effect of potassium deficiency on chemical, biochemical and physical factors commonly associated with blackspot development in potato tubers

Blackspot bruise is a physiological disorder of potato tubers resulting from mechanical damage to tissues during handling. This study examined the effect of potassium nutrition on biochemical and physical changes normally associated with blackspot bruise in potato tubers. Four potato (Solanum tuberosum L.) genotypes (TXA 763-5 [very resistant], Ranger Russet [very susceptible], Russet Burbank [susceptible], and Lemhi Russet [very susceptible]) differing in susceptibility to blackspot bruise were grown at three potassium nutrition levels (100%, 10% and 0% of the potassium in full strength Hoagland’s solution). Tubers from the three treatments were tested for their chemical, biochemical and physical characteristics commonly related to blackspot bruise susceptibility. The potential to develop malanin pigments was measured as total oxidative potential (optical density, OD₄₇₅) of clarified tuber homogenates. Tuber tissue extracts were assayed for polyphenol oxidase (PPO) activity with catechol, measured as increase in OD₄₁₀ over time. Specific gravity of tubers was determined with a brine solution series. Physical property measurements were made by impacting cores of tuber tissue in a specially designed instrumented pendulum. Shock wave speed, Young’s modulus, failure stress, and failure strain were all measured dynamically during impact. Tubers produced under both the 10% and 0% potassium regimens had almost 2x the free tyrosine of control tubers. The 0% potassium tubers had significantly higher PPO activity than the control. Both of these factors likely contributed to the significantly higher total oxidative potential that was observed in tubers from both the 10% and 0% potassium treatments. Tubers from both the 0% and 10% potassium treatments had a significantly lower Young’s modulus (a measure of stiffness), significantly lower failure stress and the shock wave of impact propagated through both of them significantly slower. Although the cultivars were significantly different in their susceptibility to black pigment development, they all responded similarly to the treatment with regards to the variables measured. The TXA-763-5 clone was much more susceptible to developing black pigments in these tests than expected. The other three cultivars performed as they do in commerce.     

Seed potato contamination with fusarial propagules and their removal by washing

Seed potatoes from Maine, New Brunswick (Canada), Wisconsin, Minnesota and North Dakota were examined during 4 years for contaminating fusarial propagules on tuber surfaces. The degree of contamination was estimated by counting the number of infections that developed on cut surfaces of 100 pieces cut from 50 tubers removed from the tops of 6 cwt bags. Lesion counts were made after 2-weeks incubation at 13 to 16 C. Of seventy-seven seed stocks examined, 29 developed lesions on 91–100% of the seed pieces. Twenty-four of these heavily contaminated stocks came from Maine and New Brunswick. For the different years,Fusarium solani was obtained from 70 to 90%, andF. roseum from 5 to 28% of the lesions cultured each year. BothFusaria were on potatoes from the different production areas. The infectious propagules were in soil washed or brushed from tuber surfaces, and surface-borne inoculum from the tubers. A preliminary report on identifying contamibefore cutting. Plant emergence and productivity were correlated with tuber contamination.     

马鈴薯脱毒种薯早收试验

1984～1985年,作者在北京延庆县田间观察马铃薯脱毒种薯早收对减少种薯感染病毒的效果。在桃蚜迁飞高峰后10～15天割秧的(以下简称割秧)病毒感染率很低:1984年0.08～0.25%;1985年1.17～1.50%。不割秧的病毒感染率很高:1984年0.83%;1985年3.30%。翌年挖取芽眼经病毒提取作PVX、PVY和TMA血清鉴定,割秧者呈阴性反应,不割秧者呈阳性。翌年将所得种薯栽种田间目测病毒症状,割秧者未见症状,不割秧者病毒株率5.5%。割秧每亩8000穴的亩产10克以上的种薯块数达32240～37600块,而不割秧正常密度的亩产10克以上种薯块数只16400～26800块。因此,早割秧密植不仅可以减少病毒感染,而且利于加大种薯繁殖系数。     

Effect of two forms of maleic hydrazide on the cell structure at the midsection,stem and bud ends of the cortical and perimedullary regions of Russet Burbank tubers

The cortical and perimedullary cells of the potato tuber increased in size when treated with the diethanolamine and the potassium salt of maleic hydrazide. The best time for maleic hydrazide application appeared to be from mid to late July. There was a greater increase in cell size in the cortex than the perimedullary region and treatment with the amine salt was more effective than the potassium salt. The cells were smallest at the bud end; however, with maleic hydrazide treatment, increase in cell size was greater in this region compared to the midsection and stem end. From late August to late September the cell size of untreated tubers remained relatively unchanged, whereas, tubers treated with the amine salt showed a 16 to 46% increase with a lesser increase with the potassium salt. The rounder form of the treated tubers can be explained by the shape and increase in cell size in the cortical and perimedullary region. Increase in cell size also may help prevent the formation of misshapen tubers.     

Transmission of potato leafroll virus to or from tuber slices by aphids feeding through a membrane

Summary Eye-bearing slices, cut from healthy potato tubers and placed between Parafilm membranes, were inoculated with potato leafroll virus (PLRV) byMyzus persicae. PLRV was detected by ELISA and by transmission tests in tuber slices and in plants grown from the slices of the susceptible cv. Désirée, but not in those of the resistant cv. Arkula. These results suggest that PLRV replication and transport within tuber phloem is controlled by specific mechanisms of resistance.M. persicae was also able to acquire and transmit PLRV toPl floridana from slices cut from tubers of infected plants. The aphids effectively transmitted PLRV from slices cut from the sprouting rose end but they failed to transmit it from slices cut from the heel end of tubers.     

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.     

Effect of production temperature of seed potatoes on subsequent yielding potential

A two year experiment was conducted to test if the temperature environment under which seed potatoes are produced significantly affects the tuber development and yield of the resultant potato plants. Six temperature regimes were established in the controlled facility of the Biotron. Two generations ofSolanum tuberosum ‘Kennebec’ tubers were grown in these environments and the yielding ability of plants produced from these tubers was tested in greenhouse facilities. Plant growth and tuber yields were similar to those which might be expected under field conditions, and marked differences in the development and productivity as a result of the production environment of the seed tubers were apparent. However, no evidence was found to support the contention that seed potatoes originating from cooler environments had any increased potential to produce higher yielding plants than comparable seed from warm environments. Even within a generation, the highest yields were found in the warmest environments, somewhat modifying the concept that the potato is strictly a cool-season crop. Other possible non-pathogenic explanations for previously observed differences in seed quality as a result of the production environment are discussed.     

Potato production and incidence ofVerticillium dahliae following rotation to nonhost crops and soil fumigation in the state of Washington

For three years, potato yields, tuber quality, and incidence ofVerticillium dahliae were measured in field plots previously cropped for one year to the following nonhosts: sudan grass, green peas followed by sudan grass (same year), spring wheat, spring wheat followed by sudan grass (same year), sweet corn and field corn. One year rotation to nonhosts did not reduce the population ofV. dahliae propagules in the soil and in only one of the three years wereV. dahliae propagule numbers in potato stems significantly reduced in plots following nonhost crops, compared with plots following potatoes. Verticillium wilt symptoms in potatoes were not reduced by one year rotation to any of these crops and only in one year in three was yield significantly increased. In two of three years, percent U.S. No. 1 tubers was increased following one-year rotation with green peas plus sudan grass, and in one of the two years, specific gravity was increased by rotation. Rotational cropping to nonhosts for two years between potatoes significantly reduced preplant soil populations ofV. dahliae propagules in the soil and in potato stems the following fall. However, soil populations in these two year rotational plots the spring following potato were not reduced compared to plots previously cropped to potatoes two consecutive years. Cropping to nonhosts for two years had no consistent effect on incidence of Verticillium wilt in subsequent potato crops. Two years’ rotation to nonhosts increased plant height and yield compared to continuous cropping to potato but not percent U.S. No. 1 tubers. The various nonhost crops all had about the same non-significant effect on yield. In two out of three years’ trials, fumigation significantly reduced both the incidence of Verticillium wilt and number ofV. dahliae propagules in stems in plots compared to plots non-fumigated. In only one trial, fumigation significantly increased tuber yields and percent U.S. No. 1 tubers.     

Incidence of potato tuber blight in Ecuador

Potato late blight, caused byPhytophthora infestans (Mont.) de Bary, is the most important biotic constraint to potato yield and productivity in Ecuador. Yields are severely reduced by foliage blight, but tuber blight has never been quantified in this country. To address this issue, three independent surveys were carried out in Ecuador to estimate the incidence of tuber infection byP. infestans. The first two (1998–1999) involved the collection and assessment of more than 8,000 tubers from the four provinces that produce the most potatoes: Carchi, Chimborazo, Pichincha, and Tungurahua. In the third survey (1999–2001), approximately 10,000 tubers were sampled from the two provinces producing the most potatoes, Carchi and Chimborazo, and from Canar and Bolivar, two provinces that produce relatively small amounts. In spite of confirmed foliage infection in most fields sampled, very few infected tubers were found. In 1999, an extremely low incidence of tuber blight (less than 0.1%) was detected in three samples (each of more than 1,000 tubers) from the province of Pichincha. In a separate survey in 1999, tuber blight was also found in three fields in the province of Carchi, but with very low incidence. Our data indicate that tuber blight does occur in Ecuador, but the incidence of the disease is extremely low. Factors that might suppress tuber blight in Ecuador are discussed.     

Integrated pest management of potato tuber moth in field and storage

Summary The potato tuber moth (PTM),Phthorimaea operculella (Zeller), is one of the most damaging pests of potatoes in field and storage. Tuber moth is active throughout the year in North Africa but is most active from late April to early August. Many cultural practices that are used by farmers to improve the yield and quality of potato can also limit the development of the potato tuber moth and minimise damage to tubers. As the farmers gain more experience with both agronomic practices and chemical insecticides, they are likely to rely more heavily on cultural practices and less on insecticides to manage PTM. Measures which could keep PTM damages in rustic and diffuse light stores to a minimum are discussed. Ideally, there is need to integrate pest management in potato fields and stores. PTM control in stores was found to be more effective if infestation in fields was kept to a minimum. Low infestation at harvest and rapid handling of the potatoes going into store established good initial storage conditions and decreased the likelihood of post-harvest losses. Biological insecticides in particular were more effective in preventing losses by insects in stores in cases where the initial level of infestation was relatively low.     

Susceptibility to Pressure Flattening Correlates with Texture Analysis of Potato Tubers

The physiological disorder referred to as pressure flattening is a cause of significant economic losses in the storage of Irish potatoes (Solanum tuberosum L.) intended for use in the fresh market. As the flattened area on each tuber becomes larger in diameter or becomes more depressed the USDA quality grade, and therefore the market value of the potatoes is reduced. Experiments were conducted to identify at-harvest which potato lots within and among cultivars were likely to pressure flatten earlier or more severely. The use of an instrumented penetrometer or texture analyzer to measure peak load required for periderm deformation at harvest appears to anticipate correctly the majority of fields from which tubers are more likely to have severe pressure flattening at six months’ storage duration. At-harvest texture analysis appears to segregate varieties according to susceptibility to deformation based on cultivar specific factors that play a role in pressure flattening development during storage. The Pearson correlation coefficient (R²=0.5481) indicates that there is a correlation between tuber texture at harvest and pressure flattened area on the tuber following storage. Testing of tubers from different fields and cultivars as the potatoes are loaded into storage, may allow growers to identify and ship potatoes that are more susceptible before they develop significant pressure flattening.     

Anatomy and compositional variation within potatoes II. Phenolics,enzymes and other minor components

Minor components, including principal phenolics and certain enzymes, are distributed within the potato tuber according to patterns that are significant to many practical problems in the growing, handling, and utilization of potatoes. Chlorogenic acid is much more concentrated in outer than in inner tissue zones; is also highly concentrated in the phloem and phloem parenchyma tissues of both cortex and perimedullary zone. Tyrosine is generally distributed but is more concentrated in the stem end than in the bud end of the tuber and probably is also more concentrated in central than in outer tissues. Results of histochemical tests on distribution of these phenolics agree in general with quantitative analytical results. Phenolases and peroxidase also show characteristic patterns of distribution. Peroxidase affects tissue differentiation and specialization and shows strong histochemical relationship with cell-wall specializations. Phenolases show association with distributions of phenolic substrates and usually are associated with cell contents. Distribution patterns are reviewed for other minor constituents, such as, iron, copper, ascorbic acid, thiamine and solanin.     

Parenchyma cell growth in potato tubers I. Different tuber regions

Enlargement rates of starch-storage parenchyma cells during growth of Kennebec and Russet Burbank potato cultivars were determined for cortical, perimedullary, and pith tissuues of bud ends, midsections, and stem ends of tubers. Average volumetric size of parenchyma cells increased 7 to 18x during growth of Russet Burbank tubers, with the greatest increases occurring in cortical and perimedullary cells of bud ends and midsections, and the least in stem ends and pith tissues. In Kennebec tubers parenchyma cells in both stem end and midsection increased only 5 to 8 x, whereas increases in bud ends ranged from 8 to 20 times. Cell enlargement to tuber enlargement ratios appproached unity early in growth of Russet Burbank tubers. As tubers increased beyond the 45 g size, cell enlargement and tuber enlargement rates were essentially equal. Calculations of cells per unit tissue volume agreed with ratio determinations. The timing of such unity appeared to be delayed in Kennebec tubers, and was not quite as pronounced as in Russet Burbank tubers. This may have been due to differences in growth rates of individual tubers in response to cultural conditions. In general, cells of harvestmature Kennebec tubers were about 60% as large as similar cells of Russet Burbank tubers.     

Transmission ofPhytophthora infestans in cut potato seed

One or two cycles of late blight transmission may occur in cut potato seed between cutting and emergence. If seed are not planted immediately, mycelium from diseased pieces can infect across adjoining cut surfaces within 8 hr. Sporangia production begins on freshly cut diseased tubers in 1–2 days, on mycelium-infected seed pieces within 4–5 days, and on spore-infected seed pieces in about 1 wk. These spores are further dispersed during handling and planting, and may infect contaminated seed in the ground, regardless of suberization. Sporangia can be transferred to healthy tubers on cutting knives, although this appears infrequent. The risk and degree of secondary spread increase with the length of time cut seed are held before planting. Such secondarily infected seed are more likely to survive and produce infected stems than the original infected tubers. Treatment of seed with appropriate fungicides immediately after cutting substantially reduces or prevents transmission of late blight to healthy seed. Certain seed treatments withoutPhytophthora-specific components may increase the risk of tuber blight.     

Analysis of <Emphasis Type="Italic">Potato Mop-Top Virus</Emphasis> Survival Probability in Post-Harvest Storage

Potato mop top virus (PMTV) induced necrosis can cause tuber quality loss at harvest and storage. Stored potatoes help maintain a constant supply of potatoes to the market and processing industry. PMTV-induced necrosis continues to develop during storage and appropriate timelines are needed for growers to make marketing decisions of their potatoes before incurring any significant quality losses. Survival analysis was used to estimate the time to event occurrence (PMTV-induced necrosis) in four (red-, russet-, white-, and yellow-skinned) potato market types across six post-harvest assessments conducted over two years. At each assessment the presence and absence of PMTV-induced necrosis was recorded and probability of tuber survival was estimated. Survival curves were significantly different among the four market type potato cultivars (Log-Rank test, P < 0.0005). Red- and russet-market type cultivars showed low and high survival probability, respectively, demonstrating that red cultivars need priority marketing. The survival probabilities decreased with increased storage time during both years, indicating that PMTV-induced necrosis development is dependent on potato cultivar and post-harvest storage. The median (50% of tubers with symptoms) survival times were estimated as 167 and 214 days for red- and other market type potato cultivars. The information from this study could potentially help growers regulate storage times for their cultivars to minimize tuber quality loss due to PMTV-induced tuber necrosis.     

Environmental conditions influence the content and yield of anthocyanins and total phenolics in purple- and red-flesh potatoes during tuber development

Changes in content and yield of anthocyanins (ACY) and total phenolics (PHEN) during development of purple- and red-flesh potato (Solanum tuberosum L.) were studied in cultivars grown in Texas and Colorado. In both locations, the ACY and PHEN content (mg/100 g tissue) decreased with tuber growth and maturity, while tuber weight (kg), total yield (Ton ha^-1) and compound yields (kg ha^-1) increased. Longer days and cooler temperatures in Colorado favored about a 2.5- and 1.4-times higher ACY and PHEN content, respectively, than in Texas-grown tubers. Harvesting potatoes at later maturity stages maximized compound yields while minimizing the glycoalkaloid content. This information can be useful to potato breeders and producers in selecting appropriate growing conditions for the enhancement of natural colorant and antioxidant yields in purple- and red-flesh potatoes for the nutraceutical and food industry.     

Anatomy and compositional variations within potatoes. IV. Total solids distribution in different cultivars

Distribution of cortical, perimedullary, and pith tissues and total solids content were determined on both a fresh and a dry weight basis for six potato cultivars grown concurrently in three locations in California. At one location, tubers harvested 80 days from planting were 1.0 to 2.5% lower in total solids than tubers harvested at later dates. The high solids cortical tissues ranged from 39 to 51% of whole tubers on a dry basis, and the amount appeared to be related to tuber shape. White Rose and Red LaSoda showed greater difference in per cent total solids between cortical and perimedullary tissues than did Kennebec, Lenape,³ Norchip, and Russet Burbank. The high total solids of the cortical tissues is particularly significant to processing losses. Any method of peeling that removes one half the linear depth of the cortical tissues can result in a loss of 25% or more of total tuber solids, depending upon cultivar and tuber shape. Tuber development and distribution of total solids and other components were previously described for Red Pontiac, Russet Burbank, and White Rose tubers obtained from the retail market (6,9,10,11). It was particularly noted that the high-solids cortical tissues, although averaging only about 6mm in depth, comprised between 40 and 50% of both fresh and dry tuber weights (6,11). Because this sort of distribution of solids is especially significant to peeling loss, possible differences in solids among cultivars and at different harvest dates were investigated.     

Effects of Different Soil Treatments on the Development of <Emphasis Type="Italic">Spongospora subterranea</Emphasis> f. sp. <Emphasis Type="Italic">subterranea</Emphasis> in Potato Roots and Tubers in the Greenhouse

Powdery scab caused by Spongospora subterranea f. sp. subterranea (Sss) causes extensive losses in potato production systems globally. Two pot experiments were established in the greenhouse in summer 2013 and winter 2014 to evaluate the effectiveness of different soil chemicals, fumigant, amendments and biological control agents (BCAs) against Sss in the rhizospheric soil, potato roots and tubers. The study used visual assessment methods to assess the effect of treatments on root galling and zoosporangia production, and qPCR to measure Sss concentration in the soil and in the potato roots and tubers. All six soil treatments, namely metam sodium, fluazinam, ZincMax, calcium cyanamide, Biocult and a combination of Bacillus subtilis and Trichoderma asperellum recorded significantly (P < 0.05) lower numbers of zoosporangia in the roots compared to the untreated control. The same effect was observed on the concentration of Sss DNA in the roots at tuber initiation. A more diverse picture was obtained when root gall scores at tuber initiation and Sss DNA in the rhizospheric soil at tuber initiation and harvesting were compared. Significant differences (P < 0.05) were also noted in disease severity, disease incidence, and tuber yield between metam sodium, fluazinam, ZincMax, calcium cyanamide and the untreated control. Calcium cyanamide gave the highest tuber yield. The study demonstrated the potential of soil treatments such as metam sodium, fluazinam, ZincMax and calcium cyanamide in managing Sss in potatoes by reducing the pathogen both in the rhizospheric soil and the roots of the potato plant.