Acta Horticulturae® "PAA2002 Toronto Joint Meeting Symposium With ISHS."
ISHS Acta Horticulturae 619. ISHS Acta Horticulturae 619: XXVI International Horticultural Congress:
Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization. [Abstracts published
from 2002 Joint Meeting NOT published in American Journal of Potato Research
Agblor, A and MG Scanlon. "Effect of Storage Period, Cultivar and Two Growing Locations on the
Processing Quality of French Fried Potatoes."
[Vol. 79, No 3, 167-172]
The source of raw potato tubers and the tubers' duration of storage have a significant effect on color and texture of French fries.
Controlling these variations is crucial to ensuring a consistent, high-quality end product. Russet Burbank and Shepody potatoes
grown at two sites in Manitoba, Canada were stores for 9 and 11 months in 1994, and for 1 and 3 months in 1995, to determine the
effects of short-term storage period, cultivar, and two tuber-growing locations on fry color and texture. French fry texture was measured
by a puncture test, and peak force and peak deformation used as indices of textural quality. Large peak forces and deformations were
assumed to be indicative of improved textural quality. Hunterlab L (lightness) value was used to determine fry color, high values being
associated with improved color quality. Fries processed for 11-month old tubers had improved color and textural quality compared to
those processed from 9-month old tubers. Fries processed after 3 months tuber storage were darker in color but firmer in texture than
fries processed from tubers after 1 month of storage. Differences in texture and color between the two cultivars were more evident with
prolonged storage; fries processed from Russet Burbank potatoes were superior in texture and lighter in color than fries made from
Shepody potatoes. With respect to site, fries processed from potatoes grown at Portage had better texture but darker color than those
processed from Carberry potatoes. It was postulated that the calcium content of the soils may be responsible for both these results.
Alyokhin, Andrei, Gary Sewell and Eleanor Groden. "Aphid Abundance and Potato Virus
Y Transmission in Imidacloprid-treated Potatoes."
[Vol. 79, No 4, 255-262]
Imidacloprid is a commonly used insecticide that is highly effective in controlling insect pests of potato. The relatively high cost of
imidacloprid provides commercial growers with a strong incentive to reduce field application rates. In the present study, we
investigated the impact of reduced imidacloprid rates on aphid abundance and potato virus Y transmission within potato fields.
In-furrow applications of imidacloprid provided better aphid control even at a reduced rate when compared to threshold-based foliar
applications, but did not suppress the spread of the non-persistently transmitted potato virus Y. Virus transmission was
significantly decreased in foliar-sprayed plots, possibly because foliar applications incapacitated aphid vectors probing or feeding on
infected plants. Despite these generally encouraging results, we still observed 2.3 to 2.7 fold increase in virus infection at foliar-treated
plots at the end of the growing season.
Andersen Aaron W, Cindy BS Tong and Darryl E Krueger. "Comparison of Periderm
Color and Anthocyanins of Four Red Potato Varieties." [Vol. 79, No 4, 249-253]
The color, anthocyanin content per given surface area, and phenolics content of tuber periderm of four different varieties of red
potatoes were compared. Three of the varieties, Norland, Red Norland, and Dark Red Norland, are members of a color sport family.
Freshly harvest 'Norland' differed significantly in color, but no anthocyanin content per given surface area, from its sports. 'Red
Norland' tubers were lighter in color than those of 'Dark Red Norland'. In general, storage resulted in darkening of tubers and, except for
the fourth variety, MN17922, a decrease in anthocyanin content per given surface area. Tubers from green-killed 'Red Norland' plants
were more purplish-red than those from vine-killed plants. Stored tubers had greater periderm total phenolics content than freshly
harvested tubers. The increase in periderm phenolics and decrease in anthocyanin content per given surface area may lead to
darkening of tubers with storage. Cell walls connecting periderm to cortex tissue of 'MN17922' tubers were thinner than those in
'Norland' tubers, which may explain why it is relatively easy to separate the periderm of 'MN17922' from its cortex.
Araji, AA and S Love. "The Economic Impact of Investment in the Pacific Northwest
Potato Variety Development Program."
[Vol. 79, No. 6, 411-420]
Genetic improvement has been the principle contributor to productivity growth in almost all field crops. The Pacific Northwest (PNW)
had the highest rate of potato yield growth combined with the least amount of varietal change in any specialized major field crop-producing
region in North America. A coordinated potato variety development program, jointly funded by the USDA, the three land grant universities,
and the potato industry in the PNW, was established in 1984. The program developed 17 new potato varieties during the 1989-2001
period, two of them are emerging as successful processing varieties. Ranger Russet, released in 1991, and Umatilla Russet, released
in 1998, possess several desired quality and production traits. The most important of these traits is 20% higher processing yield than
present varieties. Since their release, there has been significant increase in the percentage of potato area planted with these new varieties.
The weighted average adoption rate of these new varieties in the PNW in 2000 was about 16% of the area planted with potato. This
represents 32.5% of Washington’s potato acreage, 14.3% of Oregon’s potato acreage, and 9.0% of Idaho’s potato acreage.
The benefit to investments in the PNW Potato Variety Development Program attributed only to the flow of benefits from the adoption of
Ranger Russet and Umatilla Russet is estimated at over $104.3 million in year 2000 and projected to increase to $213.595 million in
year 2014 and thereafter. Rate of return to investment is estimated at 35%.
Armstrong, John D Armstrong, G Douglas Inglis, Lawrence M
Kawchuk, Tim A McAllister, Fran
Leggett, Dermot R Lynch, L Brent Selinger and KJ Cheng. "Expression of a Fibrobacter succinogenes 1,3-1,4-ß-glucanase
in Potato (Solanum tuberosum)."
[Vol. 79, No 1, 39-48]
The potential development of potato (Solanum tuberosum) as a low-cost eukaryotic system for the production of a
commercially valuable enzyme feed supplement was examined. A Fibrobacter succinogenes 1,3-1,4-ß-glucanase
[1, 3-1, 4-ß-D-glucan 4-glucanohydrolase] gene under the control of the constitutive cauliflower mosaic virus 35S promoter was
transferred into the potato cultivar, Desiree. The presence of the ß-glucanase cDNA in the plant genome of independent transgenic
potato lines was confirmed by PCR and Southern analysis. Northern analysis identified the presence of the ß-glucanase mRNA in the
leaf tissue of transgenic plants. Furthermore, western analysis showed F. succinogenes ß-glucanase accumulations of 0.1% and
0.05% of total soluble protein in the leaves and tubers, respectively. Specific activities of the enzyme in leaves (1693 units mg
-1 ß-glucanase) and tubers (2978 units mg-1 ß-glucanase) were comparable to that previously reported for
the enzyme produced in bacteria. Lyophilization of leaves had no effect on the specific activity of the ß-glucanase, and only marginally
influenced the specific activity of the enzyme expressed in tubers. Relative to the control line (cv. Desiree), tuber yields were significantly
reduced by 28%-72% in all lines expressing the F. succinogenes ß-glucanase, and microscopy showed that expression of the
ß-glucanase caused changes in cell wall structure. Results of this study demonstrate that a 1,3-1,4-ß-glucanase can be expressed in
potato tissues, and that potato plants have the potential to be used for the commercial production of heterologous enzymes.
Bains, PS, HS Bennypaul, DR Lynch, LM Kawchuk and CA Schaupmeyer. "Rhizoctonia
Disease of Potatoes (Rhizoctonia solani): Fungicidal Efficacy and Cultivar Susceptibility."
[Vol. 79, No 2, 99-106]
Rhizoctonia stem canker and black scurf is an economically important disease of potatoes in Alberta and around the world. It reduces
the quality and yield of potatoes and has become an important impediment for export of seed potatoes, especially to Mexico. Seed
treatment using fungicides, presently registered in Canada, are not effective in controlling the disease to growers' satisfaction. Field
experiments conducted to evaluate the efficacy of various fungicides showed that captan (Captan), iprodione (Rovral), mancozeb
(Tuberseal), and fludioxonil (Maxim) provide effective control of the disease. Of these fungicides, fludioxonil consistently provided superior
protection. Based on the results of this study, Maxim was registered in 2000 for control of this disease in Canada. Potato cultivars/breeding
selections showed a range of susceptibility reactions to R. solani but none of these was completely resistant to the disease.
The information on comparative susceptibility of potato cultivars will help the growers make informed decisions regarding the management
of this disease. Of six plant species (Beta vulgaris, Brassica compestris, Hordeum vulgare, Pisum sativum, Triticum aestivum, Zea
mays) most commonly used in rotation with potatoes in Alberta, none was infected by potato isolates of R. solani. The results
suggested that use of these plant species as rotation crops with potatoes in Alberta will help in reducing the development of rhizoctonia
disease in potatoes.
Belanger, G, JR Walsh, JE Richards, PH Milburn and N Ziadi. "Nitrogen Fertilization and
Irrigation Affects Tuber Characteristics of Two Potato Cultivars."
[Vol. 79, No 4, 269-279]
Nitrogen fertilization, irrigation, and cultivars affect tuber characteristics such as tuber size, specific gravity, and N concentration. Few
studies, however, have investigated the interaction of irrigation and N fertilization on the tuber characteristics of potato cultivars,
particularly in Atlantic Canada. The objective of this on-farm study, conducted at four sites in each of three years, 1995 to 1997, was to
determine the effects of supplemental irrigation and six rates of N fertilization (0-250 kg N ha-1) on the number of tubers per
plant, the average fresh tuber weight, tuber N concentration, nitrate (NO3-N) concentration, and specific gravity of the
cultivars Shepody and Russet Burbank. Nitrogen fertilization increased the average fresh tuber weight, tuber N and NO3-N
concentrations, and decreased specific gravity. Effects of increasing N fertilization on tuber characteristics were often more pronounced
for Shepody than for Russet Burbank, and for irrigated than for non-irrigated conditions. Shepody had greater average fresh tuber weight
and tuber N concentration, lower specific gravity, and fewer tubers per plant than Russet Burbank. Supplemental irrigation increased the
average fresh tuber weight and the number of tubers per plant, but it had a limited effect on specific gravity and tuber N and
NO3-N concentrations. Tuber NO3-N concentration and specific gravity were strongly related to tuber N
concentration, which in turn depended primarily on N fertilization. Incidents of lowest specific gravity and highest NO3-N
concentration occurred with a relative yield close to or equal to 1.0. We conclude that the risks of low specific gravity and high tuber
NO3-N concentration are greater when fertilization exceeds the N requirements to reach maximum tuber yield.
Benbrook, Charles M, Deana L Sexson,, Jeffrey A Wyman, Walter R Stevenson, Sarah Lynch,
John Wallendal, Steve Diercks, Randy Van Haren and Carlos A Granadino. "Developing a Pesticide Risk Assessment Tool to
Monitor Progress in Reducing Reliance on High-Risk Pesticides."
[Vol. 79, No 3, 183-199]
A methodology is presented for the development of a pesticide risk assessment tool that was used to monitor progress in reducing
use of high-risk pesticides in Wisconsin potato production. Multi-attribute toxicity factors are calculated that reflect each pesticide's
acute and chronic toxicity to mammals, birds, fish and small aquatic organisms, and compatibility with biointensive Integrated Pest
Management. These factors are then multiplied by the pounds of active ingredient of a given pesticide applied to estimate pesticide-
specific toxicity units. Wisconsin potato industry baseline toxicity units by type of pesticide and for 11 targeted higher-risk pesticides are
presented for 1995. Reductions in toxicity units from this baseline are reported for 1997 and 999, as are reductions achieved in a
commercial-scale field experiment in 2000.
Capo, AM Cammareri, F Della Rocca, A Errico, A Zoina and C
Conicella. "Evaluation for Chipping
and Tuber Soft Rot (Erwinia carotovora) Resistance in Potato Clones from Unilateral Sexual Polyploidization (2x x 4x)."
[Vol. 79, No 2, 139-145]
The aim of this work is the evaluation of tetraploid potato clones with germplasm from S. chacoense and S. phureja
for chipping and resistance to tuber soft rot (Erwinia carotovora subsp. carotovora). Tetraploid potato clones were obtained
via 2n eggs through 2x-4x crosses. Cytological mechanisms were investigated in the diploid hybrid 2n-egg producer used
as parent in the unilateral sexual polyploidization scheme the omission of the second meiotic division and cytokinesis failure at the end
of meiosis were identified with a genetic consequence equivalent to second division restitution (SDR). Tuber marketable yield, specific
gravity and chip-processing ability evaluated at harvest and after cold storage with and without reconditioning were higher in some clones
as compared to the S. tuberosum tetraploid parent. Tuber soft rot resistance, contributed by S. chacoense, was successfully
transferred to the 4x level. After inoculation with Erwinia carotovora subsp. carotovora and estimation of the rotted area, one
tetraploid clone proved to be resistant and three partially resistant. The genetic value of exotic germplasm and sexual polyploidization
strategy are discussed in relation to potato improvement.
Carputo, Domenico, Luigi Frusciante, Luigi Monti, Mario Parisi and Amalia Barone. "Tuber Quality
and Soft Rot Resistance of Hybrids between Solanum tuberosum and the Incongruent Wild Relative S. commersonii."
[Vol 79, No 5, 345-352]
Tetraploid BC3 hybrids between sexually incompatible species Solanum commersonii and S. tuberosum
were characterized for tuber quality (stolon length, tuber eye depth, chipping color from 3-month storage at 5 C, and specific gravity) and
soft rot resistance traits. For all analyzed morphological traits, except stolon length, genotypes resembled the S. tuberosum
phenotype. On average, the specific gravity of selected genotypes was quite high (1.087), and 12 of them had a value >1.090. As for
chip-processing ability, 4.8% of genotypes chipped well directly from cold storage, and 14.3% after reconditioning. All but one of these
genotypes also possessed a high specific gravity of tubers. Variability was found for resistance to Erwinia carotovora subsp.
carotovora. In particular, 24% of hybrids had a rotted area diameter < 4 mm and were classified as resistant.
The average percentage of commersonii-specific markers still present in the BC3 hybrids was 22%, ranging from 9%
to 37%. Genotypes combining good qualitative tuber traits with a wild genome content lower than the average value of
the population were selected for further breeding efforts. The importance of molecular-assisted selection is discussed.
Christ, Barbara J, Kathleen G Haynes and Bryan T Vinyard. "Inheritance of Early Blight Resistance
from Open-Pollinated 4x-2x Potato Hybrids." [Vol. 79, No. 6, 403-410]
Early blight, caused by Alternaria solani Sorauer, is a serious disease of potatoes that occurs in most potato-growing regions
in the world. There is little resistance to early blight among commercial potato cultivars. However, resistance to early blight in diploid
(Solanum phureja - S. stenotomum) potatoes has been identified, and was found to be highly heritable and readily transferred
to the tetraploid level via 4x-2x crosses. The purposes of this study were to identify good levels of early blight resistance in open-pollinated
4x-2x (Solanum tuberosum x S. phureja - S. stenotomum) hybrids selected for horticultural characteristics, to estimate broad-sense
heritability for early blight resistance in these hybrids, and to investigate the general and specific combining ability for resistance to early
blight from some of these early blight resistant tetraploid selections. Four early blight resistant clones were crossed as female parents
with four different male parents in a design II mating scheme to generate 16 families. Approximately 20 randomly chosen offspring per
family were visually evaluated for early blight resistance in 1995 and 1996 in a randomized complete block design in Pennsylvania.
Broad-sense heritability for early blight resistance among the open-pollinated 4x-2x hybrids which were originally selected for horticultural
characteristics was 0.91 with a 95% confidence interval of 0.80, 0.94. There were significant differences among female and male parents
for area under the disease progress curve, indicating the importance of general combining ability for early blight resistance in this
germplasm. The female x male source of variation was not significant, indicating that specific combining ability was not important.
The greatest number of resistant progeny were observed in families where both parents were derived from the early blight resistant
population; however, at least one highly resistant progeny was produced in all families. These results suggest that the early blight
resistance in these clones can be readily incorporated into the commercial tetraploid breeding population.
Cotes, Jose M, Carlos E Nustez, Ricardo Martinez and Nelson
Estrada. "Analyzing
Genotype by Environment Interaction in Potato Using Yield-Stability Index."
[Vol. 79, No 3, 211-218]
The plant breeding program of the National University of Colombia carried out 10 potato regional trials during 1998 and 1999 to
evaluate 15 promising potato clones (Solanum tuberosum ssp. andigena). Genotype by environment interaction was
analyzed using Kang's methodology, which links yield performance and phenotypic stability. A MACRO was implemented using the SAS
system to obtain yield-stability indices. Shukla's variance was estimated by restricted maximum likelihood (REML), which allowed handling
unbalanced data for both genotypes and replicates. In addition, a multivariate analysis methodology was developed, based on the
yield-stability index. This methodology is useful when tuber yield is categorized by size and quality, which is usual in Colombian potato
harvests.
Daayf, Fouad and Harold W (Bud) Platt. "Variability in Responses of US-8 and US-11 Genotypes of
Potato and Tomato Isolates of Phytophthora infestans to Commercial Fungicides In Vitro."
[Vol. 79,
No. 6, 433-441]
Isolates of Phytophthora infestans collected in Canada from potato and tomato plants from 1994 to 1998 were
tested for their response in vitro to equal active ingredient concentrations (1, 2.5, and 5 µ a.i./mL) of six
commercial fungicides: Acrobat MZ (dimethomorph and mancozeb), Ridomil Gold (metalaxyl-m), Dithane (mancozeb), Curzate (cymoxanil),
Bravo (chlorothalonil), and Tattoo C (propamocarb and chlorothalonil). Relative mycelial growth of isolates estimated on fungicide-amended
vs fungicide-free media was compared among isolates of the US-8 and US-11 genotypes from the two host plants. The effects of these
fungicides on spore germination of isolates from the two genotypes were also estimated. Mycelial growth of US-8 and US-11 isolates
was most affected by Bravo and Tattoo C, followed by Acrobat, and then Curzate and Dithane. Ridomil Gold was not effective in inhibiting
in vitro growth of US-11 isolates at the concentrations tested. Variations in sensitivity to different fungicides among isolates of the
same genotype collected in different years were observed. For example, based on 2.5 and 5 µ a.i./mL, potato/US-11 isolates collected
from 1995 to 1997 showed increased sensitivity to Curzate and Ridomil Gold, while decreased sensitivity was recorded with Dithane. For
US-8 isolates, responses to the fungicides varied according to fungicide and year. Variations were generally not significant for Acrobat,
Curzate, Bravo, and Tattoo C over time. Conversely, potato/US-8 isolates from 1995 and 1998 were less sensitive to Dithane and Ridomil
Gold than those from 1994, 1996, and 1997.
Davies, Corinne S, Michael J Ottman and Stanley J Peloquin. "Can Germplasm
Resources Be Used to Increase the Ascorbic Acid Content of Stored Potatoes?"
[Short Communication]
[Vol. 79, No 4, 295-299]
Freshly harvested potato tubers contain up to 50 mg/100g ascorbic acid (AA), but levels decline rapidly during cold storage. Genetic
alterations to boost the AA content of stored tubers would contribute to human nutrition and might improve tuber resistance to oxidative
damage during chilling. While studying the breeding potential of Solanum phureja germplasm, we identified a 24-chromosome
Phureja-haploid Tuberosum hybrid (clone I, US-W5295.7) that retained a twofold higher content of tuber AA than neighboring clones after
storage at 5 C. Clone I produces 2n-pollen through a mechanism genetically equivalent to first-division restitution (FDR), which transmits
much of the nonadditive genetic variance for tuber yield. We now report a survey of clone I progeny showing significant family and ploidy
effects on tuber AA levels during cold storage, consistent with the transmission of information for higher AA by FDR 2n-pollen. These
results encourage further study of 2n-gametes and wild species germplasm to breed for increased tuber AA.
del Rio, AH and JB Bamberg. "Lack of Association Between Genetic and Geographic Origin
Characteristics for Wild Potato Solanum sucrense Hawkes." [Vol. 79: No 5, 335-338]
Collecting germplasm to broaden breeding resources is an essential activity of genebanks. Research to understand how
genetic diversity is partitioned in nature might help to identify collections rich in diversity. Previous studies among wild populations of
Solanum fendleri (a disomic polyploid selfer) and S. jamesii (a diploid outcrosser) revealed no significant associations
between genetic and ecogeographic variation. Even physical separation did not predict genetic differences. In this study 28 populations
of S. sucrense Hawkes (2n=4x=48), a Bolivian species with another breeding system (polysomic polyploid oucrosser) were
evaluated. The objective was to assess whether genetic differences between populations are predicted by differences in geographic
parameters at the natural site of origin. Genetic differentiation was estimated by using 216 RAPD markers. The average genetic distance
(GD) found between pairs of populations was 31% ranging from 8% to 44%). Correlations of GD with latitude, longitude, altitude and
distance were not significant. Multiple regression analysis also confirmed that GD was not explained by the geographic parameters
used. We conclude that geographic origin data is not very useful in gauging interpopulation genetic diversity in the genebank.
Draper, Martin D, Julie S Pasche and Neil C
Gudmestad. "Factors Influencing PVY Development and
Disease Expression in Three Potato Cultivars." [Vol. 79, No 3, 155-165]
Studies were performed to investigate factors affecting symptom expression of potato virus Y infection in three potato cultivars,
Russet Norkotah, Shepody, and Red LaSoda. Quantitative enzyme-linked immunosorbent assay (ELISA) results revealed few differences
in the relative virus titer among cultivars tested. Potato virus Y (PVY) titers developed as rapidly in Russet Norkotah as in Shepody and
Red LaSoda. Additional studies were performed to determine the effect of light intensity and infections of PVY and potato virus X (PVX),
alone and in combination, on the expression of mosaic symptoms in these three cultivars. Low light intensity (270-330 uE/m
2/sec) significantly increased plant heights and severity of mosaic disease among the cultivars compared to high light
intensity (100-200 uE/m2/sec). PVX and PVY, as well as the combination of PVX and PVY in the same plant, decreased
plant height compared to the uninoculated (healthy) controls. Low light intensity and dual infections of PVX and PVY significantly increased
mosaic disease severity in Shepody and Red LaSoda, but not in Russet Norkotah. Results of these studies refute the suggestion that
Russet Norkotah is resistant to PVY infection since virus titers in this cultivar are similar to the known susceptible cultivars Shepody and
Red LaSoda. These results further suggest that while Russet Norkotah is fully susceptible to infection by PVY, it resists symptom
expression.
Edwards, Charles G, James W Englar, Charles R Brown, John C Peterson and Erik J
Sorensen. "Changes in Color and Sugar Content of Yellow-Fleshed Potatoes Stored at Three Different Temperatures."
[Short Communication] [Vol. 79, No 1, 49-53]
Yellow-fleshed potatoes, Yukon Gold, Red Gold, Saginaw Gold, Augsberg Gold, and A082283.1 were compared to white-fleshed
cultivars, Russet Burbank and Norchip, in relation to flesh color and sugar content during long-term storage. Yellow-fleshed cultivars
had higher hue angles (h°) and chroma values (C*) compared to the white-fleshed potatoes. These values were consistently higher at
all storage temperatures. Chroma values were maximum for most yellow-fleshed tubers when stored at 8.3 C for 84 days. As
expected, lower concentrations of sucrose, glucose, and fructose were observed in tubers stored at 10 C compared to those stored at
3.3 and 8.3 C. After storage at either 3.3 or 8.3 C, Saginaw Gold, Augsberg Gold, and A082283.1 accumulated lower amounts of glucose
or fructose compared to Norchip, Russet Burbank, Yukon Gold, and Red Gold. Although the yellow-fleshed clones accumulated up to 7.4
mg/g glucose or fructose when stored at 3.3 C, Saginaw Gold and Augsberg Gold responded well to reconditioning.
Fisher, David G, Kenneth L Deahl and Maxwell V Rainforth. Horizontal Resistance in
Solanum tuberosum to Colorado Potato Beetle (Leptinotarsa decemlineata Say)."
[Vol. 79, No 4, 281-293]
Horizontal resistance (HR) was assessed as a strategy to reduce potato defoliation by the Colorado potato beetle (CPB). Hybrids
among Solanum tuberosum varieties grown in Iowa were first evaluated with a detached leaflet feeding bioassay. Beginning in
1998, resistance was increased annually over three years by intermating and selecting the most resistant 1%-2% of each generation of
300-400 plants using the bioassay. When C (= mg leaf tissue consumed *neonate larva-1 over 48 h) was measured for
the 1% most-resistant genotypes of all generations grown side by side in 2000, it ranged from 6.1 mg *larva-1 in the
parents to 2.3 for progeny of the F3 generation compared to 2.73 in ND2858-1, a resistant check. Field
trials in Wisconsin showed less defoliation in the F1 and F2 selected genotypes than in the parents. A second
breeding program using more S. tuberosum parents with greater genetic diversity, and much larger breeding populations,
resulted in significantly faster accumulation of resistance, further suggesting that recurrent mass selection is effective. Foliar glycoalkaloid
analyses revealed low levels of solanine and chaconine in the F3 selections; no leptines or leptinines were detected.
Because the parents were S. tuberosum varieties in which vertical resistance to CPB is unknown, and because the resistance to
feeding from parents to the F3 resistant plants was linear and gradual while ranging from initially very low to considerably
higher in the third year, horizontal resistance is strongly implicated. The development of a significant degree of resistance after three
rounds of breeding using relatively small breeding populations suggests that HR can be developed from varieties of Solanum
tuberosum lacking initial high levels of resistance to CPB.
Groves, CL "Characterization of Phytophthora infestans from Maine during 1999 and
2000."
[Vol. 79, No 5, 325-333]
A total of 77 isolates of Phytophthora infestans was collected in 1999 and 93 isolates were collected in 2000 from
growers’ fields, home gardens, and research plots in Maine. Genotype diversity based on glucose-6-phosphate isomerase
(Gpi) allozyme analysis was greater in the collections from 2000, with six genotypes identified vs two genotypes identified in
1999. The US-8 (Gpi 100/111/122) genotype constituted 88% of the isolates collected in 1999 and 75% of those collected in
2000. The US-14 (Gpi 100/122) genotype constituted 12% and 7% of the isolates collected in 1999 and 2000,
respectively. Three new Gpi genotypes constituted 7% of the isolates collected from potato in northern Maine in 2000. A new
genotype (A1 mating type, Gpi 100/100) that was aggressive on both tomato and potato was identified from home gardens in
western Maine and constituted 11% of the isolates collected in 2000. A1, A2, and A1A2 mating types as well as self-fertile
isolates were collected in both years. Self-fertility in artificial culture appeared to be relatively common in field isolates of
P. infestans. Potential origins of the new genotypes are discussed.
Groza, HI, BD Bowen, D Kichefski, SJ Peloquin and J
Jiang. "Red Companion: A New Red Potato
Variety for Fresh Market." [Vol. 79, No 2, 133-137]
Red Companion is a medium-early maturing variety with round tubers, stable red skin, and white flesh. Its intended use is as a
tablestock variety. Red Companion has consistently outyielded Dark Red Norland in state and regional trials. The vines are more
vigorous and mature 10 days later than those of Dark Red Norland. Red Companion has a higher specific gravity and longer tuber
dormancy than does Dark Red Norland. The sloughing of Red Companion potatoes after boiling is less than for Dark Red Norland or
Red Pontiac. Less shatter bruise was found when handled in cold storage. Red Companion is less susceptible to soft rot (Erwinia
carotovora) and corky ring spot (Tobacco Rattle Virus) than Dark Red Norland and has a medium resistance to early blight
(Alternaria solani).
Guenthner, Joseph F "Consumer acceptance of genetically modified potatoes."
[Vol. 79, No 5, 309-316]
Slow consumer acceptance has inhibited the market for genetically modified (GM) potato products. Logistic growth functions were
used to model market development patterns for three comparable products -- diet sodas, frozen potatoes and microwave ovens.
Predictions of GM-potato acceptance were based on averages for the comparable products. The model predicts that consumer
acceptance will be in the introduction stage of the product life cycle for 14 years. The predicted growth stage of acceptance will begin in
2009 and last for two decades. The timeline may be compressed or lengthened depending on the influences of the biotechnology
industry and anti-GM activists.
Hayes, Ryan J and Christian A Thill. "Co-Current Introgression of Economically
Important Traits in a Potato-breeding Program." [Vol. 79, No 3, 173-181]
Wild potato species contain many traits of economic importance. Late blight (LB) resistance and cold chipping are traits desired in
potato cultivars. These traits could be co-currently introgressed if they occurred together in wild potato species. Our research objectives
were (1) to determine if variation for cold chipping exists between potato species, accessions within species, and plants within accessions
all having foliar LB resistance, and (2) to identify wild potato genotypes combining LB resistance and cold chipping. Materials include 665
genotypes from 43 LB-resistant accessions of 12 potato species having Endosperm Balance Numbers (EBN) of 1, 2, and 4, and 59
LB-resistant genotypes retained from these accessions for breeding. Potato chips were made from greenhouse-grown tubers
following storage at 4 C for six months. Chip color was scored 1-10 < 4 is acceptable by industry standards. Most of the
variation for chip color was due to differences between species. Species ranged in the percentage of acceptably chipping genotypes
(0% - 67%) with nine of 12 species having cold-chipping genotypes. Appreciable variation was present within accessions as
well. The best chipping accessions were S. verrucosum plant introduction (P1) 161173 - 4.3.3 / 0.67 (mean / proportion
acceptable genotypes), S. stoloniferum PI 250510 - 4.36 / 0.64, S. pinnatisectum PI 347766 - 4.65 / 0.35 and 275233 -
4.73 / 0.44, and S. megistacrolobum PI 195210 - 5.14 / 0.29. Eleven 1EBN genotypes from S. pinnatisectum
and S. trifidum and five 2 EBN genotypes from S. verrucosum, S. fendleri, S. stoloniferum, and S. microdontum
were identified that combined LB resistance and cold chipping. Co-current introgression would require fewer breeding cycles than
other breeding methods to identify hybrid genotypes possessing both traits.
Hayes, Ryan J. and Christian A Thill. "Introgression of Cold (4 C) Chipping from 2x
(2 Endosperm Balance Number) Potato Species into 4x(4EBN) Cultivated Potato Using Sexual Polyploidization."
[Vol. 79, No. 6, 421-431]
Cold-chipping cultivars could reduce microbial spoilage and chemical use due to cold storage of chipping potatoes. Sexual
polyploidization breeding schemes that introgress cold chipping from diploid potato species may develop improved cultivars at an
accelerated rate. The research objectives were (1) to determine the breeding behavior of cold chipping introgressed from 2x 2
Endosperm Balance Number (EBN) potato species into 4x(4EBN) progeny using sexual polyploidization, and (2) to determine
if differences exist between 2n gametes and n tetrasomic gametes for transmission of cold chipping. Experimental families of
4x(4EBN) progeny were synthesized using sexual polyploidization (2x x 4x and 4x x 2x) and 4x x 4x matings using cold-chipping
S. phureja and cultivated potato – wild species (C – W) hybrid parents. Control families from 4x x 4x matings using
as parents current industry leading germplasm were also made. Progeny were field grown and evaluated for chip color (1 light –
10 dark, < 4.0 is industry acceptable) after 3 and 6 months storage at 4 C. A larger percentage of progeny from experimental
families had acceptable chip color compared to control families, likely due to introgression of cold-chipping alleles from diploid potato
species. Out of experimental families, the best chip color means, highest phenotypic variance, and greatest percentage of acceptable
chipping progeny resulted in 2x x 4x and 4x x 2x matings. The ability of 2n gametes to transmit dominant alleles to high frequencies of
4x progeny may contribute to the superiority of 4x – 2x crosses. Breeding schemes that use sexual polyploidization in conjunction
with early generation selection should rapidly develop 4x cold-chipping germplasm.
Haynes, KG, BJ Christ, DP Weingartner, DS Douches, CA Thill, G Secor, WE Fry and DH
Lambert. "Foliar Resistance to Late Blight in Potato Clones Evaluated in National Trials in 1997."
[Vol. 79, No. 6, 451-457]
Changes in the oomycete Phytophthora infestans in the United States and other parts of the world pose a significant threat to
potato production. A continual evaluation of potato clones for resistance to late blight is necessary to identify clones with resistance and
to monitor the stability of resistance in light of the emergence of new and more aggressive strains of this pathogen. Twenty-two potato
clones (10 cultivars and 12 selections) were evaluated in 1997 for late blight resistance at seven U.S. locations. Seven late blight
differentials (R1R2R3R4, R1R2R4,
R1R3R4, R3, R8, R10, and Rmulti) were
also included in the test at five of these locations. The US-8 strain of P. infestans was present at all locations. Percent infected
foliage was recorded at approximately weekly intervals following the onset of disease. Area under the disease progress curve (AUDPC)
was calculated. The nonparametric stability statistics mean absolute rank differences (S(1)i) and variances of
the ranks (S(2)i) were used to analyze phenotypic stability. Although neither of these statistics was
significant for individual clones, both of these statistics were significant when summed over clones, indicating the importance of
genotype x environment interactions on the rankings of these clones across locations. The most late blight-resistant and susceptible
clones were the most stable; clones in the intermediate ranges were most subject to rank changes due to genotype x environment
interactions. The most late blight-resistant clones were AWN86514-2, B0692-4, B0718-3, and B0767-2. The most susceptible clones
were B0811-13, B1004-8, NorDonna, and Krantz. AUDPC was very low for the late blight differentials R8 and
Rmulti, moderately low for R10 and very high for the remaining differentials. This study is important in
characterizing the reaction of potato clones to new strains of P. infestans.
Hosaka, Kazuyoshi. "Distribution of the 241 bp Deletion of Chloroplast DNA in Wild Potato
Species." [Vol. 79, No 2, 119-123]
The common potato (Solanum tuberosum L. ssp. tuberosum) has T-type chloroplast DNA characterized by a 241 bp
deletion. To explore the maternal ancestry of the common potato, a total of 566 accessions of 35 wild species, collected mostly from
central Bolivia to northern Argentina, were determined for presence or absence of the deletion by a simple PCR assay using
primers flanking the deleted region of chloroplast DNA. Sixteen out of 80 accessions of S. tarijense, S. berthaultii, and S.
neorossii showed a shorter PCR amplified fragment. Sequencing of these fragments revealed that the same 241 bp was deleted
at the same position in these accessions. This strongly suggests that the deletion event had occurred in wild species.
Kakafumi, Kimura and Kazuyoshi Hosaka. "Genetic Mapping of a Dwarfing Gene Found in
Solanum phureja Clone 1.22." [Vol. 79, No 3, 201-204]
Dwarf plants were obtained in an F2 population of a cross between Solanum chacoense (clone chc 525-3)
and S. phureja (clone 1.22). Segregation analyses in F2 and backcross populations suggested that the dwarfism
was controlled by a single recessive gene transmitted from S. phureja clone 1.22. The dwarf plants responded to treatment
with gibberellic acid, which recovered normal growth. We named this gene 'ga2'. Linkage analysis of the
gene ga2 with RFLP and RAPD markers indicated that the gene ga2 was located on
the most or near distal end of chromosome 7.
Love, SL, R Novy, DL Corsini, JJ Pavek, AR Mosley, RE Thornton, SR James and DC Hane. "Gem
Russet: A Long Russet Potato Variety with Excellent Fresh Market and French Fry Processing Quality."
[Vol. 79, No 1, 25-31]
Gem Russet, a new medium maturing, long russet potato variety, was released in 2000 by the USDA/ARS and the experiment
stations of Idaho, Oregon, and Washington. It is suited for use in the fresh, frozen-Med processing, and dehydration markets. Total
tuber yield of Gem Russet is similar to that of Russet Burbank when grown in eastern Idaho, but lower when grown in the long-season
areas of western Idaho and the Columbia Basin of Oregon and Washington. U.S. No. 1 yield is consistently higher that that of Russet
Burbank. Tubers of Gem Russet have good processing and baked quality. Gem Russet is resistant to most external and internal
physiological defects, including second growth, growth cracks, shatter bruise, and hollow heart. It is moderately susceptible to
blackspot bruise. Gem Russet shows extreme resistance to potato virus X, resistance to common scab, and moderate resistance to early
dying. Biochemical analysis of Gem Russet tubers has shown higher solids, lower reducing sugar and glycoalkaloid content, and
higher concentration of protein and vitamin C when compared with tubers of Russet Burbank.
Love, SL, DL Corsini, R Novy, JJ Pavek, AR Mosley, RE Thornton, SR James, DC Hane and KA Rykbost.
"IdaRose: A Potato Variety with Bright Red Skin, Excellent Culinary Quality, and Long Tuber Dormancy."
[Vol. 79, No 2, 79-84]
IdaRose is a late-maturing, potato variety with round, dark red tubers. It has high yield potential and exceptionally long tuber dormancy.
IdaRose was released in 2000 by the USDA/ARS and the experiment stations of Idaho, Oregon, and Washington. It resulted from a
1982 cross of Sangre and TXA218-7. IdaRose is suited for use in both the early summer and storage fresh markets. Tuber
yield of IdaRose is higher than that of Dark Red Norland and Sangre. It has yield potential similar to or slightly lower than Red LaSoda.
Tubers of IdaRose have good internal and external quality. Culinary quality of boiled, baked, and micro-waved IdaRose tubers is excellent.
It has moderate resistance to growth cracks, hollow heart, and other defect problems. IdaRose is susceptible or moderately susceptible
to most common field diseases of potato. Tubers of IdaRose have dry matter content (19.2%) similar to other standard red varieties, and
have a relatively high concentration of sugars and low concentration of glycoalkaloids (2.4 mg/100 g).
Lulai, Edward C. "The Roles of Phellem (Skin) Tensile-related Fractures and Phellogen
Shear-related Fractures in Susceptibility to Tuber-skinning Injury and Skin-set Development."
[Vol. 79, No 4, 241-248]
The susceptibility of potato tubers to excoriation (idiom = skinning injury) during harvest is a widespread problem that results in costly
disease, defects, and shrinkage. Little is known about the physiology associated with susceptibility of immature periderm and the
development of full and final resistance to skinning injury (skin-set) upon periderm maturation. The objective of this research was to
determine the roles of phellem (skin) tensile and phellogen shear-related fractures in skinning injury and in the development
of resistance to tuber-skinning injury upon skin-set. The resistance to skinning injury was measured on potato tubers with immature and
mature periderm using genetically diverse cultivars during two growing seasons. Separate force measurements (mNm) were obtained
to determine the relative strength associated with the "total resistance to skinning" and the "phellogen shear
component" (total resistance to skinning = phellem tensile component plus phellogen shear component). The relative strength of
the "phellem tensile component" was calculated by subtracting the force measurement for the phellogen shear component
from the total resistance to skinning. The results indicate that the phellem tensile component plays a minor role in the total resistance to
skinning in immature and mature periderm. The relative strength of the phellem tensile component appeared to be nearly constant for all
time points for each cultivar and did not measurably increase as the periderm approached maturation; this indicates that the phellem/skin
tensile component does not contribute to skin-set development. However, the force required for fracture of the phellogen shear component
did increase upon periderm maturation. These results indicate that the increased strength of the phellogen shear component was the
determinant for the development of full resistance to skinning injury, i.e. skin-set. This research uncovers and defines the role of
this second component, the phellem tensile component, for incorporation into the recently conceived paradigm for tuber excoriation and
skin-set. These findings are consistent with and complement recent microscopical research which showed that the phellogen layer
of immature periderm was the single tangential plane of fracture upon skinning and that this layer of cells was no longer prone to
fracture upon development of full resistance to tuber-skinning injury. The results were similar for all cultivars tested and provide a definite
direction for future research on the biochemical changes and processes associated with phellogen cell wall strengthening, which
comprises the phellogen shear strength component.
Mahuku, George S and HW (Bud) Platt. "Quantifying Verticillium dahliae in Soils Collected
from Potato Fields Using a Competitive PCR Assay." [Vol. 79, No 2, 107-117]
A quantitative PCR assay based on the competitive PCR technique was compared to the classical soil dilution (SD) method for its
ability to estimate V. dahliae propagules directly in soils collected from fields under potato production. A strong correlation (r = 0.97)
was observed between V. dahliae propagules estimated using the quantitative PCR assay and those using the SD method.
Co-amplification of V. dahliae DNA was competitor DNA provided accurate quantification in the range of 102 to
107 spores and 1 to 100 microsclerotia/g of soil. The number of V. dahliae propagules detected in PEI soils ranged
from 4.9 to 15.6 and 0.06 to 0.5 microsclerotia/g of soil for PCR assay and SD method, respectively. The strong correlation between
PCR assay and SD method and the non significant differences between replications of PCR estimates of V. dahliae propagules
in soils (P< 0.05) show that the PCR assay is reliable and reproducible, and comparable to the SD method. This method is fast, does
not depend on the subjectiveness of the traditional plating method, and offers an improvement in speed and precision over currently
used methods. In addition, it can be extended to estimate V. dahliae propagules in other pathosystems and finds immediate and
practical use in epidemiological studies to determine the effects of various crop management propagules in the soil in order to establish
threshold levels for assessing disease risks and develop disease prediction systems.
McGrath, J Mitchell, Christie E Williams, Geraldine T Haberlach, Susan M Wielgus, Thomas F
Uchytil and John P Helgeson.* "Introgression and Stabilization of Erwinia Tuber Soft Rot Resistance into Potato After
Somatic Hybridization of Solanum tuberosum and S. brevidens"
[Vol. 79, No 1, 19-24]
Resistance to potato tuber soft rot caused by Erwinia carotovora was transferred from Solanum brevidens to the
cultivated potato over the course of four backcross generations originating from a somatic hybrid. Soft rot reactions were determined via
a tuber plug inoculation method developed during the course of these experiments. Soft rot resistance was highest in the somatic
hybrid (only ca. 20% of tubers and plugs showed evidence of severe rotting) and lowest among progeny of control potato x potato
crosses (ca. 80% of tuber plugs showed severe rot). Backcross generations involving somatic hybrids were intermediate in their
reaction, and resistance stabilized to about 60% of tuber plugs showing severe rot in the BC 2 through the BC4.
Reciprocal crosses showed no difference in the inheritance of soft rot resistance, indicating that neither S. brevidens nor
S. tuberosum donor cytoplasm had a significant effect on the expression of resistance. Crosses between BC3
siblings where no S. brevidens genetic markers were detected but resistance was segregating demonstrated a dosage effect for
soft rot resistance. We conclude that introgression of soft rot resistance has occurred and that at least one locus responsible for
resistance in S. brevidens now resides in the S. tuberosum genome.
Mojtahedi, H, JM Crosslin, PE Thomas, GS Santo, CR
Brown and JH Wilson." Impact of
Wheat and Corn as Rotational Crops on Corky Ringspot Disease of Russet Norkotah Potato."
[Vol. 79, No 5, 339-344]
Tobacco rattle virus (TRV), the causal agent of corky ringspot disease of potato (CRS), was detected by reverse transcription-
polymerase chain reaction (RT-PCR) in root tissues of field- and greenhouse-grown wheat (two) and corn (10) cultivars. TRV was also
detected in some of the same samples by enzyme-linked immunosorbent assay (ELISA), but in a low frequency. Compared to ‘
Samsun NN’ tobacco, wheat and corn appeared to be poorer hosts of TRV. However, these crops served as inoculum reservoirs
of TRV. A nonviruliferous population of the nematode Paratrichodorus allius, the vector of TRV, acquired the virus from infected
wheat and corn roots, and transmitted it to potato. ‘Russet Norkotah’ potatoes grown following TRV-infected corn and
wheat, were blemished with arcs, concentric rings and diffuse browning, characteristic symptoms of CRS. The observations presented
here suggest that wheat and corn as rotational crops will sustain TRV in a CRS problem field and the virus may cause severe damage
on subsequent potato crops.
Mpofu, SI and R Hall. "Effect of Annual Sequence of Removing or Flaming
Potato Vines and Fumigating Soil on Verticillium Wilt of Potato."
[Vol. 79, No 1, 1-7]
The effects of removing or flaming potato vines and soil fumigation on population density of Verticillium dahliae in soil, severity
of Verticillium wilt, and tuber yield were studied in a field near Alliston, Ontario, between 1993 and 1996. Vines were physically
removed or flamed using a propane flamer in September just before harvest and soil was fumigated with metam-sodium (Vapam)
at 550 L/ha in October after harvest. Vine removal had no effect on soil populations of V. dahliae, area under the disease progress
curve (AUDPC), or tuber yield. Flaming once (1993), twice (1993 and 1994), or three (1993, 1994, and 1995) times reduced the soil
population density of V. dahliae, and flaming twice (1993 and 1994) reduced AUDPC compared to the nontreated control, but had
no effect on tuber yield. Fumigation once (1993) or twice (1993 and 1994) reduced pathogen density in soil and AUDPC, but did not
increase tuber yield. Fumigation once (1993) or twice (1993 and 1994), in combination with flaming twice (1993 and 1994), was equally
and significantly effective in reducing both population density of V. dahliae in soil and AUDPC values and in increasing tuber yield
in 1995. Annual flaming of vines in combination with soil fumigation once (1993) or twice (1993 and 1994) in the fall improved the control
of Verticillium wilt of potato and realized the greatest profits.
Murphy, Agnes, Richard Tarn, Henry De Jong, Walter Arsenault and George CC Tai. "AC Sunbury:
A New light Yellow-fleshed Medium Early Table Potato Cultivar with Resistance to Golden Cyst Nematode."
[Vol. 79, No. 6, 397-402]
AC Sunbury is an attractive, round /oval, medium early table potato with light yellow flesh and very good culinary quality, especially
when baked. It produces yields comparable to Jemseg or Superior at 80 days and is resistant to the golden cyst nematode Ro1 and to
infection by PVYo. It was bred at the Potato Research Centre, Agriculture and Agri-Food Canada, Fredericton, NB, and released in 2001.
Nakagawa, Kumi and Kazuyoshi Hosaka. "Species Relationships Between a Wild Tetraploid
Potato Species, Solanum acaule Bitter, and Its Related Species as Revealed by RFLP's of Chloroplast and Nuclear DNA."
[Vol. 79, No 2, 85-98]
Solanum acaule Bitter is a wild, disomic tetraploid potato species widely distributed in the South America. In this study, species
relationships between eight accessions of S. acaule and 108 accessions of 27 morphologically closely related species were
investigated using chloroplast and nuclear DNA RFLPs. Chloroplast DNA types were determined for most of the accessions based on
restriction digestion patterns of entire chloroplast DNA. C type chloroplast DNA was common in S. acaule and S. albicans
(a hexaploid derivative from S. acaule), which was also found in S. megistacrolobum, S. sanctaerosae, S. raphanifolium, and
several other Peruvian species in series Tuberosa. Nuclear DNA was analyzed by Southern hybridization with 31 single-copy RFLP
probes. One hundred and thirty-four bands were scored, from which a UPGMA dendrogram was constructed to show overall similarities
among accessions. Solanum acaule and S. alvicans (and S. demissum) formed a cluster with a high similarity, and
then, this group was clustered with S. megistacrolobum and S. sanctae-rosae. The resulting cluster was well separated from
other clusters. Thus, we suggest that an initial tetrasomic tetraploid arose from either S. megistacrolobum or S. sanctae-rosae.
Interestingly, a Mexican hexaploid species S. demissum showed the closest similarity to S. acaule and S. albicans,
suggesting that they share a common ancestry.
Novy, RG, A Nasruddin, DW Ragsdale and EB Radcliffe. "Genetic Resistances to Potato
Leafroll Virus, Potato Virus Y, and Green Peach Aphid in Progeny of Solanum etuberosum."
[Vol. 79, No 1, 9-18]
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-bearing Solanum etuberosum (P1 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 from S. etuberosum. This germplasm could prove useful to potato breeders in the development of
virus-resistant cultivars.
Novy, RG, DL Corsini, SL Love, JJ Pavek, AR Mosley, SR James, DC Hane, CC Shock, KA Rykbost,
CR Brown and RE Thornton. "Bannock Russet: A Dual-Purpose, Russet Potato Cultivar with High U.S. No. 1 Yield and Multiple
Disease Resistances." [Vol. 79, No 2, 147-153]
Bannock Russet, a late-maturing, long russet potato cultivar, was released in 1999 by the USDA-ARS and the experiment stations of
Idaho, Oregon, and Washington. It is suitable for processing into french fries and other frozen products. Its attractive russeted
skin and excellent culinary qualities also make it suitable for fresh market. Bannock Russet, in comparisons with Russet Burbank, has
consistently produced greater U.S. No. 1 yields in trials conducted through southern Idaho. In other western trial sites, total yields of Bannock
Russet have been comparable to or smaller than that of Russet Burbank, but its percentage of undersize and cull potatoes is consistently
less. Bannock Russet is resistant to potato virus Y (PVY), Verticillium wilt, common scab, and leafroll net necrosis. It also has
moderate resistance to early blight (foliar and tuber) and Erwinia soft rot. With respect to other potato diseases/disorders, Bannock
Russet's level of susceptibility is similar to that of Russet Burbank; the exception being shatter bruise, with Bannock Russet displaying
a greater susceptibility. Cultural management guidelines have been development to minimize shatter bruise in Bannock Russet. Bannock
Russet's multiple disease resistances coupled with its low nitrogen requirement, make it a low-input cultivar that could significantly
reduce growers' production costs.
Oltmans, Shannon M and Richard G Novy. "Identification of Potato (Solanum tuberosum
L.) Haploid x Wild Species Hybrids with the Capacity to Cold-Chip." [Vol.
79, No 4, 263-268]
Cold sweetening, the accumulation of reducing sugars in potatoes stored at low temperatures, results in dark chips unacceptable to
the consumer. Developing potato cultivars that can chip directly from cooler temperatures (i.e., 3 to 4 C) requires the identification and use
of new germplasm with cold-chipping resistance. Individuals from 16 haploid x wild species hybrid families were grown at two sites and
their harvested tubers stored at 3 C for 15 wk. Following storage, individuals were evaluated for cold-chipping ability by (1) direct chipping,
and (2) reconditioning for 2 wk at 18 C prior to chipping. At both sites, approximately 1% of progeny had good chip color (<2.0 rating using
the Snack Food Association scale). Germplasm representing haploid x wild species hybrid families was evaluated for cold-chipping ability
following storage of tubers at 3 C for 15 wk, and after storage at 18 C for 2 wk. The two cold-chipping clones identified with chip color
means <2.0 were AH 66-1 and H 28-6, hybrids derived from S. raphanifolium accessions 296126 and 310998, respectively.
S. raphanifolium PI 296126 was exceptional in that chip color means of its progeny were 2.5 and 2.7 at McLeod (North Dakota)
and Crookston (Minnesota), respectively. All clones with chip color means <2.6 involved S. raphanifolium PIs 296126, 310998,
and 458384 in their parentage. Following reconditioning, the number of progeny in the good and medium chipping categories improved
from direct chipping with 14.1% of the progeny at McLeod and 3.8% at Crookston in the good chipping category. S. raphanifolium
PIs 210048 and 310998 together accounted for 100% and 50% of the clones with chip scores <2.0 at McLeod and Crookston,
respectively. Clones ranking high for chip color following direct chipping generally chipped well following reconditioning.
Pavlista, Alexander D "Skin Set Evaluation by Skin Shear Measurements." [Vol.
79, No 4, 301-307]
Skin set of tubers, an indication of maturity, is a major reason for desiccating potato vines (Solanum tuberosum L.). A
hand-held torque meter was evaluated for measuring tuber skin resistance to shearing as a measure of skin set. To demonstrate
practical use of the torque meter to growers, shear resistance must be related to tuber skinning. ‘Atlantic’ and ‘
Snowden’ potato tubers were individually measured for sldn shear resistance followed by skinning. A linear relationship
between skin shear resistance and tuber skinning was observed. The regression equations were Torque (mN*m) = 354 - (1.4 * Percent
Skinning) for Atlantic in 1995 and Torque (mN*m) = 404 - (2.2* Percent Skinning) for Snowden in 1996. The objective measuring of shear
resistance was directly related to the more subjective measuring of tuber skinning with an R-square of 0.83. In 1995, harvested Atlantic
tubers from desiccated plants were measured for skinning and resistance to torque. Skinning decreased and torque resistance increased
during the 3-wk period after the initial desiccation treatment. However, skinning remained unacceptable at one and two weeks after
desiccation regardless of treatment. Three weeks after desiccation, tubers from diquat-treated plots showed acceptable skin set levels
and a torque resistance over 325 mN*m, which the model indicated would give acceptable skin set. Unacceptable skinning and a
low torque resistance, less than 310 mN*m, remained a problem with vine flailing. Data indicated that resistance to torque exerted by
the torque meter was an accurate measurement of sldn set for harvested tubers. However, model regressions for the two round-white
chipping cultivars, Atlantic and Snowden, differed. The torque meter can be used in the field or office. A major difficulty was maintaining a
constant pressure on the tuber skin while applying the torque.
Radcliffe, Edward B and David W Ragsdale. [INVITED REVIEW] "Aphid-transmitted
Potato Viruses: The Importance of Understanding Vector Biology." [Vol.
79, No 5, 353-386]
This review addresses some of the biological complexities presented by aphid-transmitted viruses of potato, Solanum
tuberosum L., and their vectors and discusses the application of this knowledge to the management of potato viruses with particular
emphasis on seed potato production.
Redulla,CA, JR Davenport, RG Evans, MJ Hattendorf, AK Alva and RA Boydston.
"Relating Potato Yield and Quality to Field Scale Variability in Soil Characteristics."
[Vol. 79, No 5, 317-323]
Causes of within-field spatial variability in potato (Solanum tuberosum L.) yield are not well understood. To address this, a
study was conducted from 1998 to 2000 on a commercial farm in southeastern Washington. Soil samples were collected from four
center-pivot irrigated, uniformly fertilized fields on a 0.4-ha grid interval prior to potato planting and analyzed for nitrate-N, ammonium-N, P,
K, organic matter, pH, and texture. The elevation of each grid point was also recorded. Four to five days before commercial harvest,
potatoes were collected from a 3-m row length at each original grid point using a one-row digger. The potatoes were weighed, sorted
into five weight classes, and evaluated for specific gravity. Correlation and stepwise regression analyses were conducted to test
relationships among soil-based and yield variables. Factors driving yield varied between fields. Soil texture components (sand, silt, clay)
had stronger impact on yield than with the soil chemical properties we measured. However, all four fields showed an inverse relationship
between specific gravity and soil test K, although the correlation coefficients and contributions to regression models were relatively
low. Finding a general prescription formula for goals other than higher yield (e.g., nutrient leaching potential) may be feasible. The
consistent relationship of soil textural components in our models suggest that monitoring available soil water, a factor closely related to
soil texture, should be included in any future work.
Sandgren, Maria, Robert L Plaisted, Kazuo N Watanabe, Stig Olsson and Jari PT
Valkonen.
"Evaluation of Some North and South American Potato Breeding Lines for Resistance to Potato Mop-Top Virus in
Sweden." [Vol. 79, No 3, 205-210]
The necrotic symptoms (spraing) in tubers caused by Potato mop-top pomovirus (PMTV) have become a severe problem for
potato production in Scandinavia. PMTV is transmitted by the powdery scab pathogen (Spongospora subterranea) and no methods
for control are currently available. Two breeding lines (NY99 and NY103) from the Cornell University potato breeding program, two
tuberosum x acaule lines (TA3.8.3.3 and TA3.5.3.7) from the International Potato Center (CIP), and one line (IvP35) of
Solanum phureja were tested for resistance to PMTV in field trials in Sweden in 1998 and 1999. In both years, NY99 had a low
incidence of PMTV infection in tubers, and the infected tubers showed a low accumulation of PMTV, indicating that NY99 is a promising
new source of resistance to PMTV for breeding programs. Furthermore, it may be suitable for cultivation in Scandinavia, which, however,
needs to be evaluated in more extensive field trials.
Simko, Ivan. "Comparative Analysis of Quantitative Trail Loci for Foliage Resistance to
Phytophthora infestans in Tuber-bearing Solanum species."
[Vol. 79, No 2, 125-132]
Previously published data for potato foliage resistance to late blight were examined in a combined analysis to determine how
the genetic backgrounds of the host and pathogen affect the occurrence of resistance QTLs. Data from 19 diploid populations and one
tetraploid population that originated from at least 12 different tuber-bearing Solanum species were included. Comparative
analysis across all populations revealed three highly active genomic regions on the distal parts of chromosomes 3, 4 and 5. The region
most consistently detected that conferred foliage resistance in Solanum was located on chromosome 5, near marker locus GP21.
A previously identified cluster of three race-specific R-genes on chromosome 11 was not associated with polygenic resistance.
Statistical examination of active QTLs indicates that congruence among QTLs is significantly affected by both genetic relatedness of
mapping populations and race of Phytophthora infestans to 0.20 found in unrelated mapping populations tested with different
races of Phytophthora infestans. Analysis of resistance mapping tests provided statistical evidence for the occurrence of
race-specific QTLs in tuber-bearing Solanum. The highly conserved genomic regions identified in the comparative analysis are
likely to be good candidates for gene cloning or marker assisted selection in potato breeding programs.
Sunseri, Matthew A, Dennis A Johnson and N Dasgupta. "Survival of Detached Sporangia of
Phytophthora infestans Exposed to Ambient, Relatively Dry Atmospheric Conditions."
[Vol. 79, No. 6, 443-450]
The effect of duration of exposure, daily weather conditions, and exposure to direct or indirect sunlight on survival of sporangia of
Phytophthora infestans under ambient, relatively dry atmospheric conditions was evaluated. Viability of sporangia was assessed
by determining the proportion of potato tuber slices or leaflets that became infected after inoculation with exposed sporangia. The
maximum survival time of sporangia was 24 h under moderately cool (mean of 15 C) and dry conditions (RH < 25%). Sky conditions
were sunny during daylight hours during this exposure. Infection seldom occurred when sporangia were exposed directly to sunlight;
only 25 of 566 (4.4%) groups of sporangia caused infection. Of these 25 groups, 23 (92%) had been exposed to mean temperatures
below 33 C for 4 or fewer hours. Binary logistic regression analysis of the data showed that duration of exposure, direct sunlight, and
type of day were all significant factors affecting survival of sporangia. Long exposure in direct sunlight limited survival. Survival of
sporangia was more likely to occur on cool, cloudy days and cool, rainy days than on other day-types.
Tsror, L (Lahkim) and I Peretz-Alon. "Reduction of Silver Scurf on Potatoes by Pre-
and Post-storage Treatment of Seed Tubers with Imazalil." [Vol. 79,
No 1, 33-37]
Control of silver scurf on daughter tubers was obtained by imazalil applied to seed tubers as a pre- or post-storage treatment
or as a furrow treatment (at time of planting), in three field experiments. Post-storage and pre- and post-storage combination treatments
provided consistent results. The most effective treatment in the first and second experiments was the combined pre- and post-storage
application of imazalil. However, separate pre- and post-storage treatment also significantly reduced the incidence compared with the
non-treated control. No differences were observed between dosages of 15 and 30 g a.i. of imazalil per ton of seed tubers. Although
furrow treatment at planting time (1.5 1/ha) significantly reduced silver scurf incidence on daughter tubers, it was less effective than seed
treatments. However, the combined treatment of pre-storage application and furrow treatment significantly reduced the disease and was
more effective than the single pre-storage seed treatment. In the third experiment, a reduction of disease incidence and severity index was
obtained by post-storage treatments or with the combination of pre- and post-storage applications.
Walworth, JL and DE Carling. "Tuber Initiation and Development in Irrigated and Non-Irrigated
Potatoes." [Vol. 79, No. 6, 387-395]
Tuber initiation and development are processes basic to potato production and are particularly critical in areas with short growing
seasons. It is important to know how and to what extent management decisions affect these processes in order to maximize the yield
of marketable tubers. A two-year field study, conducted in south central Alaska, examined top growth, tuber initiation, and tuber
development in eight potato cultivars grown with and without irrigation. Plants of the cultivars Allagash Russet, Bake-King, Green
Mountain, Kennebec, Lemhi Russet, Russet Burbank, Shepody, and Superior were harvested weekly throughout the growing season,
and top dry weight, numbers of tubers, and individual tuber fresh weights were recorded. Top dry weight was reduced by moisture
stress shortly after emergence in 1993, and about one month following emergence in 1994, when early-season soil moisture was
greater. The weight of tubers was similarly affected within approximately 5 wk of emergence in 1993 and 6 weeks in 1994. Tuber
weight at harvest was increased two- to three-fold by irrigation in all cultivars. The number of tubers each plant set was affected by
irrigation in most, but not all, cultivars. Some varieties (Lemhi Russet in 1994, Allagash Russet both years) set more tubers than
were maintained through the growing season. Tuber remnants found during sample collection indicated that tuber reabsorption
had occurred. Irrigated Green Mountain had more than one tuber initiation period during the season, whereas other varieties such
as Shepody maintained a relatively constant number of tubers following initial tuber set. Tuber size distribution at the end of the
growing season showed that larger tubers were favored by irrigation.
Zlesak, David C and Christian A Thill. "Variation for 2n Pollen Production and Male Fertility in
Wild Solanum Germplasm Resistant to Phytophthora infestans (Mont.) de Bary (US-8)."
[Vol. 79, No 3, 219-229]
Wild potato species possess genetic variability for valuable traits including resistance to Phytophthora infestans, the casual
agent for potato late blight disease. Breeding schemes using 2n gametes are a powerful tool for introgressing these traits. Forty-five
plant introductions (PIs) across 12 Solanum species representing various Endosperm Balance Numbers (EBN) and having
resistance to P. infestans (US-8, isolate ND 95-2) were screened for 2n pollen production and male fertility. Species evaluated
were 2x(1EBN) S. bulbocastanum, S. cardiophyllum, S. pinnatisectum, and S. trifidum; 2x(2EBN) S. berthaultii, S.
megistacrolobum, S. microdontum, and S. verrucosum; 4x(2EBN) S. fendleri and S. stoloniferum; 6x(4EBN)
S. guerreroense; and 2x(unknown EBN) S. polyadenium. Acetocarmine staining and cytological analyses were
used to determine 2n pollen production and pollen stainability from genotypes grown across three locations. Based on frequency,
genotypes were assigned to 2n pollen reproduction categories (0< 1%, Low=1%-10%, Medium=11%-60%, and High<
60%) and pollen stainability categories (0< 1%, 1=1%-5%, 2=6%-10%, 3=11%-20%, 4=21%-50%, and 5<
50%). Eleven of the 12 species and 37 of the 45 PIs examined contained genotypes producing < 1% 2n pollen with ranges of
0%-63.6% and 0%-81.8%, respectively. Dependence was found between location and pollen stainability, EBN and pollen stainability, but
not for location and frequency of genotypes of 2n pollen. Stability for 2n pollen production was observed across environments. Among the
1EBN germplasm, dependence was found between 2n pollen and pollen stainability. Resistance to P. infestans was found to be
independent of 2n pollen production; therefore, identifying genotypes combining 2n pollen production, fertility, and resistance to P.
infestans was possible.
Zvomuyal, Francis, Carl J Rosen and J Creighton Miller, Jr.. Response of Russet Norkotah
Clonal Selections to Nitrogen Fertilization. [Vol. 79, No 4, 231-239]
The low vine vigor and high N requirement of ‘Russet Norkotah’ may lead to N loss and groundwater contamination on
coarse-textured soils. Recent clonal selections from Texas have produced strains that have larger and stronger vines, which may alter N
requirements. This two-year study examined the N use efficiency (NUE), yield, and quality of Russet Norkotah strain selections fertilized
with different N levels on a Hubbard loamy sand in central Minnesota. The selections, Texas Norkotah Strain (TXNS) 112, TXNS 223, and
TXNS 278 were grown with standard Russet Norkotah under irrigated conditions and received total N levels of 28, 112, 224, or 336 kg
ha-1. Total, marketable, and large (>340 g) tuber yields increased linearly (P<0.05) with rate of N application in 1998
but not in 1997. The genotype main effect was not significant for any of the tuber yield parameters measured based on fresh weight. Vine,
tuber, and total dry biomass yields were 116%, 5.8%, and 13.2%, respectively, higher with the selections than Russet Norkotah. Harvest
index (HI), or the proportion of total dry matter partitioned to tubers, was 7% greater for Russet Norkotah than the TXNS selections,
reflecting the larger vine growth of the selections. The selections accumulated significantly higher N in the vines (0.113 kg kg-1 N)
than the standard clone (0.053 kg kg-1 N) as N rate increased from 28 to 336 kg ha-1, and the difference
between the selections and the standard clone was larger at higher N rates than at lower N rates. Russet Norkotah partitioned 10% more N
to tubers than did the TXNS selections, reflecting the difference in HI between the standard cultivar and its clones. Nitrogen recovered from
fertilizer N applied in addition to the 28 kg ha-1 starter N (NUE28) averaged 36% and varied little with genotype,
N rate, or cropping year. Biomass accumulation from similar N additions (AUE), however, was significantly higher for the selections than
Russet Norkotah at 112 kg N ha-1 in 1997 only. At low N rate (112 kg ha-1), the selections had higher
physiological use efficiency (PUE28) (mean 45.9 g g-1) than Russet Norkotah (25.9 g g-1).
Results from this study demonstrate that, although N recovery was similar for the four genotypes, the Texas Norkotah strains produced
greater biomass than Russet Norkotah per kg N applied at low rate in 1997 and per kg of fertilizer N absorbed by the plant in both years.
However, under the conditions of this study, higher biomass of the selections did not translate into a marketable yield advantage over the
standard cultivar.