Afek, U, Janetta Orenstein and E Nuriel. "Using HPP (Hydrogen Peroxide Plus) to inhibit potato
sprouting during storage." [Vol. 77, No. 1, 63-65]
Potatoes (Solanum tuberosum L.) samples, cv. Desiree, were treated for sprout control and stored at 10+/- 1 C for 6 months.
Those treated four times with HPP (hydrogen peroxide plus), applied with the "Tabor Atomizing System", had a 0% rate of
sprouting. Those treated with CIPC (chloro-isopropyl N-phenyl carbamate) also had no sprouting, while the nontreated control had 84%.
A single treatment with HPP or CIPC resulted, after 6 months of storage at 10+- 1, in sprouting rates of 61 and 58%, respectively, vs. 87%
in the untreated control.
Afek, Uzi, Janeta Orenstein and Ephraim Nuriel. "Using the Tabor Atomizer System to maintain
weight and firmness in stored potato tubers." [Vol. 77, No. 3, 203-205]
A new fogger - the Tabor Atomizer System - features unique atomizers, based on compressed air and water.
The droplets produced have a very small mass (less than 10 m,) and behave like a dry cloud, producing 96%-98% relative humidity (RH)
without depositing free water on the tubers. After 6 months of storage at 10 C, with 96%-98% RH applied with the Tabor Atomizer System
(room A), 92%-94% applied with a spin-disk humidifier (room B), and 82%-86% with no added humidity (room C), the weight losses for
stored potatoes were 2%, 7%, and 12%, respectively. The firmness of the tubers expressed as newtons (N) required to penetrate the tubers
before storage and after 6 months in room A, B, or C was 76, 74, 68, or 63 N, respectively.
Al-Kahtani, Hassan A, Hamza M Abu-Tarboush, Atif A Abou-Arab, Adnan S Bajaber, Mohamed Asif
Ahmed and Mohamed A El-Mojaddidi. "Irradiation and storage effects on some properties of potato starch and use of
thermoluminescence for identification of irradiated tubers."
[Vol. 77, No. 4, 245-259]
The effect on properties of starch isolated from Ajax and Diamant potatoes freshly harvested and irradiated immediately after harvest
and after two weeks with 0.05, 0.10., 0.15, and 0.20 kGy were reported. Changes due to post-irradiation storage
up to six months at two different conditions (5 C, 90+/- 2% RH and 20 C, 79+/- 5% RH) were also studied. Swelling power (SP) slightly
decreased or remained unchanged with different irradiation dose, but the effect of timing of irradiation after harvest was significant. Doses
of 0.2 and 0.15 kGy significantly (p < 0.05) increased solubility, particularly at 90 C solubility
temperature compared to lower doses. Decrease in viscosity with increasing dose immediately after irradiation was observed in both
varieties but was more pronounced in Diamant. However, changes were dependent on variety, irradiation dose, timing of irradiation, and
post-irradiation storage conditions. Viscoamylograph test showed that 0.2 kGy significantly (< 0.05)
increased transmission temperature (TT) and temperature at maximum viscosity (TMV), but decreased the maximum viscosity
immediately after irradiation. The same trend was established during the post-irradiation storage time, particularly in Ajax starch,
regardless of timing of irradiation or storage conditions. Thermoluminescence (TL) glow curves exhibited qualitative differences between
irradiated and unirradiated tubers during the entire storage period, but dose estimation could not be determined.
Bamberg, JB, C Singsit, AH del Rio and EB Radcliffe. "RAPD analysis of genetic diversity in
Solanum populations to predict need for fine screening." [Vol. 77, No. 4, 275-278]
Populations of two wild potato species known to have high levels of green peach aphid, PLRV, and PVY resistance (Solanum
polytrichon PI 184170 and S. stoloniferum PI 160226) were assessed for heterogeneity of RAPD markers among plants within
these populations and among other populations of the same species. These species are reputed selfers, so were suspected of being
relatively inbred. About 75% of the bands segregating within their species were fixed within these populations, and more than 90% of the total
bands observed within these populations were fixed. These levels of homogeneity were not significantly different from those of an inbred
population of S. albicans known to be extremely homogeneous. It can be expected that populations such as these, that are relatively
homogeneous, are also more likely to be homogeneous for specific traits of interest. Thus, there may be less need for rigorous fine
screening of these material at the genotype level before making breeding crosses.
Bamberg, JB "Germination of gibberellin sensitive Solanum (potato) botanical seeds soaked
in GA3 and re-dried."; [Vol. 77. No. 3, 201-202]
Soaking true seeds of potato species in gibberellin (GA) solution prior to sowing has been shown to enhance
germination. However, it is often more convenient to sow dry seeds. Model seedlots were selected which had very high germination when
soaked in GA and very low without it. (i.e. very dependent on GA). These were assumed to provide a sensitive test for germination decline
when GA-treated seeds are re-dried. Re-drying and storage for one week had little effect on final percent germination and no effect on the
efficacy of GA for enhancing germination. There appears to be little risk in applying this technique whenever it makes seed sowing more
convenient.
Baritelle, Andre, Gary Hyde, Robert Thornton and Rick Bajema. "A Classification system for
impact-related defects in potato tubers." [Vol. 77, No. 3, 143-148]
The type of tuber bruise that occurs for a given severity of impact indicates the condition of that tuber in relation to
its impact sensitivity. This article describes a system for classifying such bruises. Such information is important because sensitive tubers
can be re-conditioned (e.g., temperature and/or hydration can be adjusted) to reduce risk of bruising during harvesting and handling. Each
class of bruise is described, illustrated, and related to tuber condition. The literature review illustrates the inadequacies of previous bruise
evaluation systems in relating bruise type to tuber condition. Growers, processors, storage operators and fresh packers can use this system
to make informed decisions on adjusting modifiable factors such as temperature, hydration level, and impact velocity to reduce
impact-related defects during harvesting and handling of potatoes.
Belanger, G, JR Walsh, JE Richards, PH Milburn and N Ziadi. "Yield response of two potato
cultivars to supplemental irrigation and N fertilization in New Brunswick." [Vol. 77, No. 1, 11-21]
Nitrogen and water are important factors influencing potato production, and crop response to these two factors may vary with cultivars.
The yield response of two potato cultivars (Russet Burbank and Shepody) to six rates of N fertilization (0-250 kg N
ha-1) with and without supplemental irrigation was studied at four on-farm sites in each of three years,
1995 to 1997, in the upper St-John River Valley of New Brunswick, Canada. On average, irrigation increased total yield from 31.9 t
ha-1 without irrigation to 38.4 t ha-1 with irrigation and marketable
yield from 25.6 t ha-1 without irrigation to 30.7 t ha-1 with irrigation.
Potato yields were increased by irrigation at nine out of the 12 sites, and the irrigation response was similar for both cultivars. Nitrogen
fertilization significantly increased both total and marketable yields at all sites except one. The yield response to N fertilization was great with
irrigation. The N fertilization rate (Nmax) required to reach maximum total and marketable yield, however, was similar with and without
irrigation. A large variation in Nmax was observed among sites. With irrigation, Nmax varied between 158 and 233 kg N
ha-1 for total yield, and between 151 and 250 kg N ha-1 for
marketable yield. There was no interaction between N fertilization and potato cultivar for both total and marketable yields. The two
cultivars had similar total yields (35 t ha-1). Shepody, however, had a greater marketable yield
(28.9 t ha-1) than Russet Burbank (27.4 t ha-1). Our results indicate
that the response to two of the most significant factors of potato production, irrigation and N fertilization, varies greatly with sites and climatic
conditions, and that field specific recommendations are required for the optimum management of N and irrigation.
Boiteau, G, LM Moore and D Wattie. "Comparative analysis of Aphid vector behavior in response to
potato plants grown from field tubers, minitubers or plantlets." [Vol. 77, No. 2, 71-75]
The greater sensitivity of aphid vectored diseases of potato plants originating from plantlets or minitubers compared
to plants originating from field grown tubers could not be explained by changes in probing behavior, by increased aphid movement between
plants or by greater levels of aphid colonization favorable to virus spread. The number of seconds to first probe, the duration and number of
seconds before the long probe and the duration of the long probe were statistically similar on all plant types. The average residency time of
green peach aphids on each plant type was also statistically the same. Winged Myzus persicae (Sulzer) (green peach aphid) landed in greater
numbers on older than on younger plants regardless of plant type. This suggests that the level of aphid colonization in determined by a
combination of factors such as height, surface and age of plants but not by plant origin. Where virus vectors are present early in the season,
the greater number of aphids landing on the relatively older and larger transplants may contribute to higher infection levels, but later in the
season plant physiological factors favorable to virus multiplication or translocation are more likely factors.
Brodie, BB, Maria Scurrah and RL Plaisted. "Release of germplasm resistant to multiple races of
potato cyst nematodes." [Vol. 77. No. 3, 207-209]
Seeds of three progenies segregating for resistance to two pathotypes of Globodera rostochiensis (Ro1 and Ro2)
and two pathotypes of G. pallida (Pa2 and Pa3) are being released by the Cornell University Experiment Station and the USDA/ARS.
This resistance is in a form suitable for North American production and was developed for use in the event that pathotypes of G. pallida,
which are prevalent in many other potato production areas of the world, are ever introduced into North America. The source of the resistance is
germplasm obtained in 1984 from the International Potato Center in LaMolina, Peru. The combined resistance in this germplasm is from
S. tuberosum ssp andigena and S. vernei. Resistance to PVY is also segregating in two of these progenies.
Brown, CR, H Mojtahedi, GS Santo, P Hamm, JJ Pavek, D Corsini, S Love, JM Crosslin and PE Thomas.
"Potato germplasm resistant to corky ringspot disease." [Vol. 77, No. 1, 23-27]
Potato germplasm was assessed for resistance to corky ringspot disease (CRS) incited by transmission of
tobacco rattle virus (TRV). TRV is transmitted by the stubby root nematode, Paratrichodorus allius, in the Pacific Northwest, and
characterized by necrotic areas in the tuber. Four tests were conducted at two different problem fields in Umatilla, OR and Pasco, WA. The
fields differed in the virulence of the virus isolates. Some clones and named varieties showed resistance only in the field with the relatively
mild Umatilla isolate, while others remained symptomless at both sites. The host suitability of test potatoes to three P. allius
populations from the region was determined in greenhouse pot tests, and expressed as reproductive values
[Rr = (final population of nematode at 55 days) / (initial population)]. The
Rr values for the nematodes were not correlated with resistance ratings based on visual scoring of CRS
symptoms in field grown potatoes. Thus, it appears that CRS resistance is based on reaction of potato genotypes to virus and not the vector.
The availability of resistant clones in in vitro form is indicated.
Coleman, Warren K and Shirlyn E Coleman. "Modification of potato microtuber dormancy during
induction and growth in vitro or ex vitro." [Vol. 77, No. 2, 103-110]
Prolonged or highly variable dormancy can be a significant impediment to the efficient use of potato (Solanum tuberosum L.)
microtubers by the seed industry. In the present study, reductions in microtuber dormancy duration were obtained in cultivars commonly
used by the processing industry (Kennebec, Russet Burbank and Shepody). This was achieved by modifying microtuber induction media
and applying various dormancy-released treatments after harvest, with or without prior storage. An 8 h photoperiod, instead of continuous
darkness during microtuber induction and development, increased microtuber yield while reducing dormancy duration. Dormancy duration
was also shortened by increased sucrose concentration during microtuber induction under an 8 h photoperiod. As sucrose was increased
from 4 to 16% under an 8 h hotoperiod, mean dormancy duration decreased by 86 d for Shepody, 65 d for Kennebec and 46 d for Russet
Burbank. During the ex vitro storage period, 24 h treatment with bromoethane vapor (from 0.22 ml liquid BE per l volume) or
bromoethane vapor followed by a 3 d treatment of 60% CO2/ 20%
O2/20% N2 resulted in a rapid dormancy release of freshly harvested
microtubers. These dormancy-releasing treatments significantly increased minituber yields under greenhouse conditions for all cultivars
when compared to untreated controls. Increased minituber yields were also observed when dormancy release treatments were applied to
microtubers after storage at 6 C for 8 weeks. The results demonstrate that microtuber dormancy duration can be manipulated during
growth in vitro or ex vitro. However, optimization may require cultivar-specific protocols.
Copp, LJ, RW Blenkinsop, RY Yada and AG Marangonia. "The relationship between respiration
and chip color during long-term storage of potato tubers. [Vol. 77, No. 2, 279-287]
Processing potatoes, both sprout inhibited and untreated, were evaluated for respiration rate and chip color during storage under
commercial conditions (12 C, approximately 95% relative humidity, in darkness) following three growing seasons. While absolute
respiration rates varied depending upon growing season and treatment, all cultivars and treatments studied during the 1995, 1996, and
1997 storage seasons showed similar respiration profiles. The initial stage following curing and sprout inhibition treatment (if applied)
showed essentially constant respiration rates for a period of time varying from two to 15 weeks, depending upon growing season, treatment
and cultivar. This was followed by a stage that showed a linear increase in respiration rates. In some cases the respiration rates eventually
stabilized, or decreased. There was an apparent correlation between respiration trends and chip color changes in most cases, though
the statistical significance varied between cultivars and seasons. Qualitative analysis of the data showed that the point at which respiration
rates began to increase coincided with the onset of the decline in chip color quality. These trends suggest that measurement of tuber
respiration may provide a non-destructive and in situ method to predict changes in processing quality of stored potato tubers.
Daayf, F and HW (Bud) Platt. "Changes in metalaxyl resistance among glucose phosphate
isomerase genotypes of Phytophthora infestans in Canada during 1997 and 1998."
[Vol. 77, No. 5, 311-318]
A total of 930 isolates of Phytophthora infestans collected during 1997 and 1998 from commercial potato and tomato fields,
home gardens, and potato storages in Canada was analyzed for glucose phosphate-isomerase (Gpi) genotype, mating type, and
resistance to metalaxyl. Both mating types and diversity in resistance to metalaxyl were detected within and among Gpi-genotypes.
Pathogen populations were dominated by the 100:111:112 Gpi-genotype (characteristic of US-8) in all the provinces where late
blight was detected, except in 1997 in British Columbia (BC) where the 100:100:111 Gpi-genotype (characteristic of US-11)
predominated. Gpi-genotypes 100:111, 111:122, and 100:122 (characteristic of US-7, US-10, and US 14/US-17, respectively) were
less common. Nearly all of the isolates with the 100:100:111 Gpi-genotype were the A1 mating type, except for a few collected in BC
in 1997. A majority of isolates with the 100:111:122 Gpi-genotype were A2 except for a few found in Quebec in 1998. Based on
colony growth on media amended with 1, 10, or 11 µg/ml metalaxyl, the 100:100:111 Gpi-genotype isolates had higher
levels of resistance to the fungicide in 1998 compared to 1997. In 1998, levels of metalaxyl resistance was higher within the 100:100:111
Gpi-genotype whereas it was lower within the 100:111:122 Gpi-genotype, when compared to 1997. BC was the only
Canadian province where an increase in metalaxyl resistance within the 100:111:122 Gpi-genotype was recorded between 1997
and 1998. Isolates from leaves had higher metalaxyl resistance levels than stem or tuber isolates, regardless of genotype.
Edwards, Linnell, Anja Volk and Jack R Burney. "Mulching potatoes: aspects of mulch
management systems and soil erosion." [Vol. 77, No. 4, 225-232]
Intensive potato production occupies much of the sloping arable land of Prince Edward Island, Canada, and is at the center of soil
erosion concerns in this province. Corrective considerations have turned recent attention to mulching, but there is limited knowledge of
its workability or effectiveness in potato systems. This study looks at the effect of mulching on soil loss from potatoes grown on standard
erosion plots, and examines a relatively simple approach to assessing soil-surface splash detachment (splash erosion) under mulch-
management systems with potatoes. Three sizes of splash cup (25, 50, and 100 mm in diameter) were used under simulated rainfall
at 150 mm*h4 for 10 minutes to measure splash erosion on potato plots under mulch-management
systems which, respectively, left surface coverage of -5%, -15%, and -20%. The lowest straw coverage gave up to 56% more erosion
than either of the two higher coverages. The 25-mm splash cup yielded 14% more sediment splash than the 100-mm splash cup on
the basis of unit surface area of soil in the splash cup (unit area). Regression modeling of unit-area splash against straw cover showed
an exponential decay in splash detachment with increasing straw cover. On the erosion plots, soil loss with mulching was half of what it
was without mulching; and soil water retention was 5% greater with mulching.
Goth, Robert W and Kathleen G Haynes. "Evaluation of potato clones for severity of Verticillium Wilt,
yield and specific gravity in Maine.;quot; [Vol. 77, No. 1, 89-94]
In 1994 and 1995, the effect of Verticillium wilt, caused by Verticillium dahliae and V. albo-atrum, on tuber yields,
number and weight of U.S. No. 1 and B size tubers, and specific gravity was studied in northern Maine, an area with a short growing
season. Seven clones (four resistant and three susceptible) were evaluated in a split-plot design with three replications. Clones were the
whole-plot factor, and seed pieces in sub-plots were either uninoculated or inoculated with 50 ml of 4 x 104
cfu/ml Verticillium spp. at planting. Individual plants were scored for Verticillium wilt symptoms before harvest on a 1=<3%
wilt to 10=> 97% wilt. Differences among clones for wilting and specific gravity were significant. The inoculation treatment had no effect
on any of the tuber traits measured. However, there were significant clone x inoculation interactions for most tuber traits. Reductions in yield,
weight and number of U.S. No. 1 potatoes, and specific gravity were greater in the Verticillium wilt susceptible clones than in the
resistant clones. These results suggest that breeding clones with resistance to Verticillium spp. will reduce yield losses, while
maintaining tuber size and specific gravity under disease pressure.
Hosaka, Kazuyoshi, Hiroshi Matsunaga and Keiichi Senda. "Evaluation of several wild
tuber-bearing Solanum species for scab resistance." [Vol. 77, No. 1, 41-45]
One hundred accessions of 18 wild diploid potato species were screened for resistance to scab through three cycles of selection, from
which a total of 322 clones were selected as resistant. The putative ancestral species of the cultivated potatoes (Solanum bukasovii, S.
canasenseand S. multidissectum) produced resistant clones with significantly higher rates. Thus, these are primary gene sources
for conferring scar resistance to cultivated potatoes.
Huaman, Zosimo, Rodomiro Ortiz and Rene Gomez. "Selecting a Solanum tuberosum subsp.
andigena core collection using morphological, geographical, disease and pest descriptors."
[Vol. 77, No. 3, 183-190]
One of the largest and most diverse clonally propagated potato collections of cultivated potato species is maintained at the
International Potato Center (CIP). Almost 75% of this collection is S. tuberosum subsp. andigena (hereafter andigena)
cultivars. The first step to select a core collection of this subspecies was to identify duplicate accessions of the same cultivar using
comparisons of morphological characters and electrophoretic banding patterns of total proteins and esterases. This reduced the number of
accessions in the collection from 10,722 to 2,379. The number of accessions of the same cultivar in the original collection ranged from 1
to 276. This is a report on the selection of a core from the 2,379 morphologically different cultivars using morphological, geographical,
and evaluation data. A total of 25 morphological descriptors were scored from all 2,379 andigena cultivars. A phenogram was
constructed from these data using a simple matching coefficient and the unweighted pair group method using arithmetic averages. We
decided to include in the cure a proportional sample consisting of approximately the square root of the number of accessions from each
first geographical division (state, department, or province) of countries where andigena was collected. Accessions were chosen first
to represent the widest morphological diversity and to maximize geographical representation of the clusters distributed on the main
branches of the morphological phenogram. Second, the representative accession of each cluster was also chosen considering data on
resistance to diseases and pests, dry matter content, and number of duplicate accessions identified in the original collection. The resulting
core has 306 accessions (12.86%) from eight countries from Mexico to Argentina. The full breeding potential of Andean farmer-selected
potato cultivars that have been maintained for centuries in their center of diversity remains unknown. A thorough evaluation of their reaction
to diseases and pests and other desirable traits is now feasible because the selected andigena core set covers the broadest
genetic base that is available in ex situ conservation.
Huaman, Z, R Hoekstra and JB Bamberg. "The inter-genebank potato database and the
dimensions of the available wild potato germplasm." [Vol. 77, No. 6, 353-362]
The Association of Potato Inter-genebank Collaborators (APIC) constructed of a database of all wild potato holdings of the most
important potato genebanks in Europe, the United States, Peru, and Argentina. The Inter-genebank Potato Database (IPD) now contains
data of 11,819 wild potato accessions conserved in several potato genebanks. The collector's number is the key identifier used to merge
all databases into the IPD. A total of 7,112 different wild potato accessions were identified, which comprise 5,306 accessions with known
collector's numbers. The IPD passport database showed that almost 30% of accessions, held in APIC genebanks are from Argentina, a
country that comprises less species diversity than Peru and Bolivia. These latter countries are represented by 24% and 20% of
accessions, respectively. APIC genebanks maintain 188 Solanum taxa out of more than 230 recognized by the latest comprehensive
treatment of potatoes (Solanum sect. Petota) by Hawkes (1990). About 60% of the accessions comprise only 20 taxa represented by
785 to 92 accessions each. Conversely, 2% of the accessions comprise 72 taxa and are represented by five or fewer accessions each.
About 70 taxa are not available in any genebank. The IPD evaluation database comprises 5,603 records with data from more than 33,000
evaluations of wild potato accessions. Fifty-five traits are summarized, including the reactions of the accessions to 12 pathotypes or races
or strains of 12 fungi, four bacteria, 12 viruses, one viroid, 13 nematodes, and seven insects; response to heat and cold stress; and
content of dry matter, starch, vitamin C, amylase, reducing sugars, and glycoalkaloids. About 30% of the wild potato populations screened
showed various levels of resistance to most of the diseases and pests evaluated. The IPD database is available on the Internet at
www.potgenebank.org
Kalifa, A, NN Barthakur and DJ Donnelly. "Phosphorus reduces salinity stress in micropropated
potato." [Vol. 77, No. 3, 179-182]
The present study was conducted to determine whether varying the sodium chloride (NaCl) concentrations in Murashige and Skoog
( MS) basal medium could affect radiophosphorus (32P) uptake, and whether high NaCl stress was
moderated by the availability of inorganic phosphorus (Pi) to micropropagated potato (Solanum tuberosum L. cv. Russet Burbank).
The kinetics of 32P uptake in micropropagated potato plantlets was studied over a 48-hr interval in MS
medium containing 1.25 mM Pi and varying concentrations of NaCl (0 to 120 mM). The 32P activity of the
top-most trifoliate leaf increased considerably with time, but decreased significantly as medium NaCl concentrations increased. The 32P
activity of the root tips at 48 hr was greater, but translocation of Pi into leaves was less, as medium NaCl concentration increased. As
medium Pi concentration was increased from 0 to 2.5 mM, in the presence of 120 mM NaCl, 32P
activity decreased in root tips but translocation into the top-most leaves occurred more efficiently.
Kefi, Servet, Alexander D Pavlista, Michael M Meagher and Paul E Read. "Invertase activity as affected
by cytokinin-like compounds during potato tuberization in vitro." [Vol 77, No. 1, 57-61]
Acid invertase plays an important role in plants by hydrolyzing sucrose. Compounds exhibiting cytokinin activity were examined for their
effects on acid invertase activity at three tuberization stages of potato, Solanum tuberosum L. Single nodal segments from the
cultivar Atlantic were cultured on Murashige and Skoog (MS) medium with 6% sucrose and maintained under a 16-hr photoperiod. Media
were supplemented with either 2 mg kinetin/1, 0.1 mg thidiazuron/1, 1.0 mg AC243,654/1 (a benzyl nitroguanidine), or 0.1 mg AC239,604/1
(a phenyl nitroguanidine). Basal acid invertase activity was measured in stolon segments at three morphologically distinct tuberization
stages: (1) "hook," (2) "swelling," and (3) "initiation." The onset of tuber initiation was significantly
advanced by kinetin and thidiazuron compared to controls. Stolons elongated during the hook and swelling stages until tubers were
initiated. Basal acid invertase activity in stolons cultured on control medium significantly increased from hook stage to swelling stage and
then decreased slightly when tubers were initiated. At the hook stage, highest basal acid invertase activity occurred when the segments were
treated with kinetin and thidiazuron. Kinetin and thidiazuron induced basal acid invertase activity significantly decreased following the hook
stage to tuber initiation. Basal acid invertase activity were significantly lower in stolons treated with nitroguanidines that the control activity
following the hook stage of development. During the swelling and tuber initiation stages, nitroguanidines-treated segments showed
reduction in basal acid invertase activity similar to segments treated with kinetin and thidiazuron treatments. Tuber initiation was preceded
by a stimulation of basal acid invertase activity followed by a decrease prior to tuber initiation. Kinetin and thidiazuron stimulated enzyme
activity early in the growth of stolons which may have resulted in faster stolon growth and in earlier tuber initiation. The two nitroguanidines,
although able to mimic many cytokinin effects in bioassays, did not seem to act in the same way as kinetin.
Kozub, JG, DR Lynch, GC Kozub, LM Kawchuk and DK Fujimoto. "A relational database system
for potato breeding programs." [Vol. 77, No. 2, 95-101]
Using a desktop database management system (DBMS), a relational database system was developed to replace outdated systems
for data storage, retrieval and summary in a potato breeding research program. The new system allows for easy and efficient access,
storage and interrelation of potato data, and automated reporting functions to support presentation and analysis requirements of the
research program. DBMS tools and programmed functions provide summary information pertaining to such areas as potato plant
genealogy and progeny performance in early selection, regional adaptation and disease resistance trials. Database structures have been
implemented to facilitate the collection and certification of new data interface to a hand-held data collection computer, and transfer report
data and charts to standard word processing and presentation software. The concepts and techniques used in the construction of this
database system can be applied to other potato and plant breeding programs.
Lulai, Edward C. "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."
[Vol. 77, No. 5, 303-310]
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 included 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 x 4mm). Excised, elictor-treated 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 elicted 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.
Lynch, DR, JC Miller, Jr, LM Kawchuk, CA Schaupmeyer, J Holley, J Panford, DK Fujimoto, D Waterer, J
Wahab, B Rex and MS Goettel. "AC Stampede Russet: A high-yielding oblong russet cultivar for the French fry and fresh market
industries." [Vol. 77, No. 4, 241-244]
AC Stampede Russet has a main crop maturity, and the tubers reach maximum size in western Canada in early to mid-September.
The tubers are attractive with russet skin, shallow eyes, an oblong shape, and are very uniform in size. The cultivar is suitable for French fry
or fresh market (count carton) production. It appears to perform best under irrigated conditions. The cultivar provides the industry with a
russet-skinned, dual purpose russet cultivar with high yield, low defect levels, excellent fresh market appeal, and good storage quality for
both the French fry and fresh market industries.
Mosley, AR, SR James, KA Rykbost, DC Hane, CE Stanger, CC Shock, JJ Pavek, DL Corsini, JC Miller, Jr,
SL Love, RE Thornton, DG Holm, and RE Voss. "Century Russet: A high-yielding fresh market cultivar with Verticillium
resistance." [Vol. 77, No. 3, 161-165]
Century Russet, a high-yielding, late-maturing variety suitable for fresh tablestock use, was jointly released in 1995 by Agricultural
Experiment Stations in Oregon, Idaho, Washington, Colorado, California, and Texas and the USDA Agricultural Research Service.
Extremely high yields have been observed for Century Russet in variety trials conducted in Oregon and throughout the western United
States under a wide range of soil and climatic conditions. Century Russet produced 40 percent higher marketable yields than Russet
Burbank and 67 percent higher marketable yields than Russet Norkotah in 11 regional trials conducted over a three-year period in seven
western states. Uniform tuber shape, high yields or count carton sizes, and attractive tuber appearance make Century Russet well suited
for the fresh market industry. It is not recommended for chipping or processing into frozen products because of low solids and dark fry color.
Century Russet is highly resistant to Verticillium wilt and consistently develops less hollow heart, brown center, and other internal
defects than Russet Burbank. It requires more time between vine kill and harvest than Russet Burbank for adequate tuber maturity and
skin set. Bruised Century Russet tubers are susceptible to early blight and Fusarium infection.
Mosley, AR, SR James, CC Shock, DC Hane, KA Rykbost, BA Charlton, DG Holm, SL Love, DL Corsini,
JJ Pavek and RE Thornton. "Russet Legend: A full season long russet for processing and fresh market use."
[Vol. 77, No. 2, 77-81]
Russet Legend, a moderately late maturing variety especially suitable for frozen French fry processing but also acceptable for tablestock
use (boiling and baking), was jointly released by the Agricultural Experiment Stations of Oregon, Colorado, Idaho, and Washington, and the
U.S. Department of Agriculture in 1998. Russet Legend was evaluated in irrigated trials from 1990 to 1992. Total yields were similar to those
of Russet Burbank, but Russet Legend produced higher marketable yields. In three years of regional trials at up to 13 locations in seven
western states, Russet Legend averaged 47.3 Mg/ha marketable yield compared with 36.5 Mg/ha for Russet Burbank and 33.6 Mg/ha for
Russet Norkotah. Russet Legend has consistently achieved lighter fry color and higher specific gravity than Russet Burbank. Russet
Legend is less susceptible to Verticillium wilt than Russet Burbank or Russet Norkotah. It is susceptible to PLRV and net necrosis,
and expresses PVY foliar symptoms clearly. Russet Legend is less susceptible to tuber infection and decay caused by Phytophthora
infestans than Ranger Russet and Russet Norkotah. Russet Legend is less susceptible to hollow heart, brown center, growth cracks,
and sugar ends than Russet Burbank.
Mosley, AR, SR James, DC Hane, KA Rykbost, CC Shock, BA Charlton, JJ Pavek, SL Love, DL Corsini
and RE Thornton. "Umatilla Russet: A full season long russet for processing and fresh market use."
[Vol. 77, No. 2, 83-87]
Umatilla Russet, a moderately late maturing variety especially suitable for frozen French fry processing but also acceptable for
tablestock use (boiling and baking), was jointly released by the Agricultural Experiment Stations of Oregon, Idaho, and Washington and the
U.S. Department of Agriculture in 1998. Umatilla Russet was evaluated in irrigated trials in Oregon from 1988 to 1997, and in western
regional trials from 1989 to 1991. Total yields were similar to those of Russet Burbank, but Umatilla Russet produced higher marketable
yields. In three years of regional trials at up to 13 locations in seven western states, Umatilla Russet averaged 40.5 Mg/ha compared with
a 32.4 Mg/ha for Russet Burbank. Umatilla Russet fry color and specific gravity are consistently equal to or better than for Russet Burbank.
Umatilla Russet is less susceptible to Verticillium wilt than Russet Norkotah, less susceptible to net necrosis than Russet Burbank, and
resistant to PVX. It is susceptible to PLRV and expresses foliar symptoms of PVY more clearly than Russet Norkotah. Umatilla Russet is
less susceptible to tuber infection and decay caused by Phytophthora infestans than Ranger Russet and Russet Norkotah. Umatilla
Russet is less susceptible to hollow heart, brown center, growth cracks, and sugar ends, but more susceptible to blackspot and shatter
bruise than Russet Burbank.
Omer, MA, DA Johnson and RC Rowe. "Recovery of Verticillium dahliae from North American
certified seed potatoes and characterization of strains by vegetative compatibility and aggressiveness."
[Vol. 77, No. 5, 325-331]
Samples of tubers collected from commercial potato seed lots produced across North American were assayed for Verticillium
dahliae. V. dahliae was successfully isolated from 65 to 224 seed lots tested, a successful isolation rate of nearly 30%. Vegetative
compatibility of the isolates was assessed through complementation tests using nitrate non-utilizing mutants. all V. dahliae isolates
belonged to vegetative compatibility group (VCG) 4. Of the 162 isolates recovered, 64% belonged to VCG 4A, 33% to VCG 4B, and 3% to
VCG 4AB. All 39 of the isolates tested in the greenhouse on potato cv. Superior were pathogenic to potato. Disease symptoms developed
earlier, were more severe, and plants died earlier when inoculated with VCG 4A compared to 4B isolates. As a group, AUPC values were
significantly higher (p=0.05) for VCG 4A than for 4B isolates. These data suggest that (1) commercial certified seed tubers from diverse
locations are commonly infected with V. dahliae and thus may serve as primary sources of the pathogen; (2) potato isolates of V.
dahliae in North America belong to VCG 4A and 4B and these strains are widely distributed via seed tubers; and (3) VCG 4A and 4B are
distinct pathotypes of V. dahliae that vary in their aggressiveness to potato.
Perez, EE, DP Weingartner, E Hiebert and R McSorley. "Tobacco rattle virus detection in potato
tubers from northeast Florida by PCR and tissue blotting." [Vol 77, No. 6, 363-368]
Tobacco rattle virus (TRV) was detected in potato tubers by reverse transcription of RNA followed by amplification of the cDNA by
polymerase chain reaction (PCR). Primer A complementary to residues 6555 to 6575 and printer B identical to residues 6113 and 6132
of TRV-SYM RNA-1 were used. After amplification, the 463- bp fragment was cloned, sequenced, and compared to sequences of
TRV isolates from Europe and Canada. Nucleotide sequence homology of the 16 kDa ORF between the FLA TRV-isolate and the CAN,
TCM, PLB, PSG, and SYM TRV-isolates were 94%, 94%, 93%, 90%, and 90%, respectively. A nonradioactive biotin-labeled probe
detected TRV by tuber tissue blotting. Nematode-transmitted TRV was also detected in bait plants of Nicotinan tabacum cv
Samsum, N. clevelandii, and Petunia hybrida by enzyme-linked immunsorbent assay (ELISA).
Platt, HW (Bud), ES Plissey, GR MacKay, M Adams, MK Hinkle and E MacDonald. "Sustaining potato
crop, land and industry health beyond the year 2000: current issues and future needs."
[Vol. 77, No. 5, 333-352]
A symposium presentation of The Potato Association of American Pathology Section held on Prince Edward Island, Canada (3-7 August
1997). The conference theme was "Link to the Future." The speakers both informed and challenged attendees on the vital issues
that must be understood and acted upon to ensure a healthy potato industry worldwide beyond the year 2000.
Platt, HW (Bud) and G Mahuku. "Detection methods for Verticillium species in naturally infested
and inoculated soils." [Vol. 77, No. 4, 271-274]
The detection and identification of three Verticillium species in field soils with a polymerase chain reaction (PCR)-based assay
was compared to the traditional planting assay method. The two methods were both able to detect the common Verticillium species in soils
although the PCR method detected V. tricorpus in three soil samples that the traditional method did not. In addition, the PCR assay
was rapid, efficient , and required only 1 to 2 days for positive identification whereas the traditional methods required 4 to 8 weeks. The traditional
method provided a quantitative measure of pathogen propagules in the soil with population levels ranging from 0 to 21, 625 colony-forming
units per gram of soil. However, it was not able to differentiate between the weakly pathogenic V. albo-atrum strain 2 and the more
aggressive V. albo-atrum strain 1, but these two were distinguished with the PCR Assay. Results from this study demonstrate that
when symptoms of Verticillium wilt are observed in potato plants in the field, the major Verticillium wilt pathogens present in
field soils can be rapidly and reliably detected by the PCR assay.
Reid, NB, BP Marks, AR Gonzales and TJ Siebenmorgen. "Effects of physical properties on
incidence of breakage in canned white potatoes." [Vol. 77, No. 5, 319-324]
During commercial sterilization of whole white potatoes, mild to severe breakage sometimes occurs. Physical properties of potatoes
were measured before and after sterilization. These included major diameter, minor diameter, density, dry matter content, amylographic
viscosity, compressive breaking strength, and tensil breaking strength. The experimental data were evaluated in terms of mean values
from 33 different truckloads sampled at a commercial canning facility (60 tubers sampled per load). These properties were statistically
compared to the incidence of breakage in sterilized potatoes. The results did not show significant relationships between any of the raw
potato properties and the incidence of breakage. However, several properties of the sterilized potatoes (major diameter, peak viscosity,
peak viscosity temperature) were linearly related to breakage (R2=0.84).
Rokka, Veli-Matti, Jari PT Valkonen, Airi Tauriainen, Leena Pietila, Renata Lebecks, Ewa Zimnoch-Guzowska
and Eika Pehu. "Production and characterization of "second generation" somatic hybrids derived from protoplast fusion
between interspecific somatohaploid and dihaploid Solanum Tuberosum L." [Vol. 77, No. 3, 149-159]
Protoplasts were fused to produce somatic hybrids between a triploid (2n=3x=32-34) interspecific somato-haploid between
Solanum brevidens Phil. and S. tuberosum L., and a dihaploid (2n=2x=24) anther-derived line of S. tuberosum
cv. Van Gogh. A total of 265 plants were regenerated from protoplast fusion derived calli and their hybridity was verified using fusion partner
specific RAPD markers. These "second generation" somatic hybrids were aneuploid pentaploids (2n=5x=51-65) with a 2C DNA
content ranging from 3.36 to 4.43 pg, which corresponded to the sum of the 2C values of each of the fusion partners (somatohaploid:
2.22 pg; and the dihaploid line of cv. Van Gogh: 1.87 pg). Most of the "second generation" somatic hybrids were vigorous, but
variable in morphology. They were extremely resistant to PLRV and they had tolerance to PVY infection derived from the somatohaploid
fusion partner. Even though most of the "second generation" hybrids tuberized, the tuber morphology was variable and most
were poorly shaped. In Erwinia soft rot resistance tests, the tubers showed higher level of resistance than the tetraploid S.
tuberosum cultivars, the dihaploid S. tuberosum fusion partners and the hexaploid somatic hybrids between S. brevidens
and S. tuberosum. The "second generation" somatic hybrids were all male sterile and failed to produce berries or seeds.
Santini, Matias, Elsa Lucila Camadro, Olga Noemi Marcellan and Luis Ernesto Erazzü. "Agronomic
characterization of diploid hybrid families derived from crosses between haploids of the common potato and three wild Argentinean
tuber-bearing species." [Vol. 77, No. 4, 211-218]
Five diploid hybrid families derived from crosses between haploids of three Argentinean cultivars and three diploid wild species,
Solanum gourlayi, S. chacoense and S. spegazzinii, were evaluated in a field experiment in Balcarce. All plants were
androsterile and, thus, could not be screened for 2n pollen production. Data on agronomic tuber traits were statistically analyzed.
Differences among families were non-significant for tuber number/plant, but were significant for tuber weight/plant and dry matter content
(with values above 21.0% in two of them). The relative frequencies of tubers in the categories established for size, skin texture, and eye
depth were family dependent, but they were family independent in the categories established for tuber shape and skin color. Great
morphological variability was detected for all the traits studied, and plants with high yield and high dry matter content were identified.
These families can be used as sources of germplasm in breeding and to explore heterotic responses in 2x x 4x crosses, given the capacity
of some plants to produce 2n eggs, as found in a related investigation.
Sarquis, JL, NA Coria, U Aguilar and A Rivera. "Glycoalkaloid content in Solanum species and
hybrids from a breeding program for resistance to late blight (Phytophthora infestans)."
[Vol. 77, No. 5, 295-302]
As part of an effort to study the relationship between the "glycoalkaloid trait" and genetic resistance to late blight
(Phytophthora infestans), glycoalkaloid content in tuber and foliar tissues from a wide genetic background within
Solanum, including S. demissum, S. iopetalum and 15 hybrids selected from a backcrossing breeding scheme was
determined. Analysis of variance indicated significant genotype effect on total glycoalkaloid, solanidine, a-solanine, and
a-chaconine content in both tubers and leaves. Tubers from wild potato species commonly contain glycoalkaloids in
concentrations that exceed international health regulations for human consumption (20 mg/100 g fresh weight). In this study,
S. demissum and S. iopetalum were highest in total tuber glycoalkaloids among all materials tested, with 70.4 and 76.2
mg/100 g fresh weight, respectively. In contrast, both commercial cultivars had the lowest concentration, but below the safety limit.
Solanine was more abundant than chaconine in all but one genotype. All hybrids were intermediate to low in total glycoalkaloids. Except
for the two wild species, glycoalkaloid concentration in leaves of all genotypes studied was at least twice that in tubers, with glycosylated
forms accounting for more than 80% total glycoalkaloid content. Correlation between tuber and foliage alkaloids was poor. In view of the
observed field resistance to late blight, it was concluded that tuber glycoalkaloid content may not be responsible for such resistance.
Schlisler, David A, Patricia J Slininger, Gale Kleinkopf, Rodney J Bothast and Richard C Ostrowski.
"Biological control of fusarium dry rot of potato tubers under commercial storage conditions."
[Vol. 77, No. 1, 29-40]
Lack of effective chemicals impedes control of Fusarium dry rot of stored potato tubers destined for processed and table stock use.
Biological control of dry rot incited by Gibberella pulicaris (anamorph=Fusarium sambucinum) has been demonstrated in
laboratory studies but not in commercial storage environments. Several Gram-negative bacterial strains that were efficacious and
amenable to production in liquid culture in laboratory studies were selected for pilot studies in Idaho and for bin trials at commercial
storage houses in Idaho and North Dakota. In the first year of pilot studies, Pseudomonas fluorescens S22:T:04
(=1 x 108 cfu/ml) decreased dry rot caused by G. pulicaris by 19% when coinoculated with the pathogen
compared to controls and to the fungicide thiabendazole (TBZ) applied at label rates. In second year pilot studies, P. fluorescens
P22:Y:05 and Enterobacter cloacae S11:T:07 (=4 x 108 cfu/ml) reduced the severity of disease
incited by G. pulicaris (25% and 17% average disease decrease, respectively) when antagonists were applied after pathogen
inoculum. Treatment effects on dry rot that developed from inoculation with Nectria haematococca (anamorph=Fusarium solani
var. coeruleum) were variable and influenced by interactions between antagonists, a wetting agent, and TBZ. In commercial storage
bin trials, E. cloacae S11:T:07 reduced naturally occurring levels of dry rot by an average of 21% compared to 14% for TBZ,
demonstrating that this antagonist was effective when produced using a liquid culture medium and methodology that approximates
commercial practices for producing biomass.
Sedegui, Mohamed, Robert B Carroll, Allen L Morehart and Daryl P Whittington. "Etiology of
potato early dying in Delaware." [Vol. 77, No. 5, 289-294]
Greenhouse and field plot experiments along with surveys of commercial potato fields were conducted to determine the etiology of
potato early dying in Delaware and its impact on yield of Solanum tuberosum cultivar Superior. Verticillium dahliae was the
primary pathogen causing early dying, and no increase in disease severity or yield loss was observed when plants were inoculated with
both V. dahliae and Colletotrichum coccodes. The field survey showed that V. dahliae was the predominant pathogen in
symptomatic plants, and the nematodes were not essential in association with Verticillium to cause early dying. Disease severity was the
same in the presence of a low population or absence of nematodes.
Serrano, Carolina, Patricio Arce-Johnson, Herbert Torres, Marlene Gebauer, Monica Gutierrez, Mauricio
Moreno, Xavier Jordana, Alejandro Venegas, Julio Kalazich, and Loreto Holuigue. "Expression of the chicken lysozyme gene in
potato enhances resistance to infection by Erwinia Carotovora subsp. Atroseptica." [Vol. 77, No. 3, 191-199]
Infection of potato plants and tubers with the bacterium Erwinia carotovora subsp. atroseptica produces blackleg and
soft rot diseases, which cause significant losses to crops and stored potatoes. In order to obtain resistance against this bacterium, the
gene chly encoding the enzyme lysozyme from chicken was introduced into potato plants (ev. Desiree) via Agrobacterium-
medicated transformation. Sixty-three and 69 transgenic potato clones were evaluated in the greenhouse for resistance to blackleg and
soft rot diseases, respectively. Results reported in this paper indicate that 21%-29% of the potato clones showed increased resistance to
infection by the bacterium E. c. subsp. atroseptica T7, as revealed by a reduced severity of blackleg or soft rot symptoms.
Nine clones showing different levels of resistance were selected for further molecular analysis. The number of copies of the transgene
integrated in the plant genome of these clones was estimated by Southern blot analysis. The level of transgene expression, detected by
Northern blot analysis, correlated with the level of resistance detected in these clones.
Sowokinos, JR, CC Shock, TD Stieber and EP Eldredge. "Compositional and enzymatic
changes associated with the sugar-end defect in Russet Burbank potatoes." [Vol. 77, No. 1, 47-56]
This study was initiated to determine the starch-sugar composition and the activities of relevant enzymes of carbohydrate metabolism in
Russet Burbank (cv.) potatoes exhibiting the sugar-end defect. The frequency of sugar-end tubers was increased by applying a single,
transient, moisture-deficit stress period following tuberization. The following properties were unique to sugar-end tubers compared to normal
tuber tissue. (1) Starch and total solids decreased markedly while glucose content increased 15-fold, (2) The concentration of Suc was
markedly lower, (3) Pi was slightly but significantly increased, (4) The activities of UGPase and Susy decreased nearly 3- and 2-fold,
respectively, (5) The activity of AGPAse decreased 50%, (6) The ratio of STPLase to AGPase shifted over 3-fold in favor of starch mobilization,
(7) Basal AcInv activity (assayed in the presence of inhibitor) increased 7-fold during storage, (8) Tuber Glc concentration showed a better
correlation to basal AcInv activity than to total AcInv activity (inhibitor destroyed), (9) Kinetic analysis suggested that the level and/or
effectiveness of the AcInc inhibitor was decreased in the sugar-end tuber tissue. These results are discussed in relation to metabolic
changes which occur in converting a starch storing tuber to one primarily involved with starch mobilization.
Spooner, David M, Antonio Rivera-Pena, Ronald G van den Berg and Konrad Schuler. "Potato
germplasm collecting expedition to Mexico in 1997: taxonomy and new germplasm resources."
[Vol. 77, No. 4, 261-270]
Wild potato (Solanum sect. Petota) germplasm has been collected in Mexico on nine major expeditions, as determined
by 20 collections or more from each expedition currently at the United States potato genebank, the National Research Support Program-6
(NRSP-6). These have resulted in 609 accessions with good collection data. In addition, NRSP-6 has germplasm of approximately 90 other
Mexican collections that are unspecific regarding date or place of collection. This expedition was funded to collect those remaining
collections with no or little germplasm: Solanum clarum, S. x edinense, S. hintonii, S. hjertingii var. physaloides, S.
leptosepalum, S. lesteri, S. macropilosum, S. x michoacanum, S. x sanbucinum, and S. stenophyllidium. In addition, some
species and species groups (species groups indicated in parentheses) have unresolved additional field collections. These are (S.
agrimonifolium and S. oxycarpum), (S. brachycarpum, S. guerreroense, S. hougasii, and S. iopetalum - the
S. brachycarpum complex), (S. fendleri, S. papita, S. stoloniferum- the S. stoloniferum complex), S. leptosepalum,
and S. macropilosum. We conducted a wild potato germplasm collecting expedition in Mexico from August 22 to October 31, 1997.
Our 103 collections, 71 as germplasm collections, provide the first germplasm samples for S. hjertingii var. physaloides, S.
leptosepalum, and S. macropilosum. They provide additional germplasm of the rare species S. clarum, S. x edinense, S. lesteri,
S. x michoacanum, S. x sampbucinum, and S. stenophyllidum. We additionally gathered germplasm and field data to help
resolve taxonomic difficulties in S. agrimonifolium and S. oxycarpum, the S. brachycarpum complex, and the S.
stoloniferum complex.
Ulrich, D, E Hoberg, W Neugebauer, H Piemann and U Darsow. "Investigation of the boiled potato
flavor by human sensory and instrumental methods." [Vol. 77, No. 2, 111-117]
The flavor of boiled potatoes was investigated using sensory and instrumental methods to get basic information concerning sensory
features and aroma compounds for use in breeding research and quality control. The sensory odor profiles of three genotypes were found to
differ especially in negative sensations like "burnt", "fodder" and "musty." The aroma volatiles were
isolated by a modified simultaneous steam distillation and extraction method. Nineteen character impact compounds of boiled potato
aroma were pointed out by gas chromatography with nitrogen specific detection, gas chromatography - mass spectrometry and gas
chromatography - olfactometry. The comparison of the quantified odor impressions in three genotypes by chromatography - olfactometry
revealed the substances responsible for the typical boiled potato odorants and off-flavor notes.
Virgen-Calleros, V Olalde-Portugal and DE Carling. "Anastomosis groups of Rhizoctonia solani
on potato in central Mexico and potential for biological and chemical control."
[Vol. 77, No. 4, 219-224]
Anastomosis group (AG) identity of Rhizoctonia solani isolates collected from potato plants growing near Leon, Guanajuato,
in central Mexico was determined. In samples from 15 fields, we found AG-3 and AG-4 with a frequency of 73.5% and 26.5% respectively.
AG-4 was found only during the flowering stage of plant growth, whereas AG-3 was present on plants at every stage of development. The
efficacy against R. solani, in vitro and in situ, of certain biocontrol agents (Bacillus subtilis, Gliocladium virens)
and fungicides (Pencycuron, Tolcoflos-methyl, Fluazinam, Azoxystrobin) was assessed. Certain Bacillus strains collected from
the field inhibited in vitro growth of isolates of certain AGs. Only Pencycuron and Tolcoflos-methyl inhibited AG-3 100% in vitro,
whereas in the field, Azoxystrobin and Pencycuron showed the highest efficacy against development of sclerotia on tubers.
Whitworth, Jonathan L, Alvin R Mosley and Gary L Reed. "Monitoring current season potato
leafroll virus movement with an immunosorbent direct tissue blotting assay." [Vol. 77, No. 1, 1-9]
A direct tissue blotting assay (DTBA) was used to track the movement of potato leafroll virus (PLRV) from newly infected foliage to the
tubers. Plant and tuber characteristics were recorded to assess plant growth stage at inoculation and PLRV effect on yield. Russet Burbank
potatoes were planted at different times in 1991 and 1992 to provide plants of different maturities which were then inoculated using PLRV
carrying aphids. Aphids were allowed to feed two to three days after which an insecticide was applied. Stems and tubers were tested
periodically for PLRV with DTBA after inoculation. Indexed tubers were grown out and ELISA tested in the greenhouse the following winter to
confirm results of summer serological tests. Plant age affected percentages more consistently than did inoculation date. When plants
approximately 43 days from planting were inoculated at different dates, early inoculation produced a higher percentage of infected plants.
Conversely, when plants approximately 62 days from planting were inoculated at different dates, late inoculation resulted in a higher
percentage of infected plants. However, early inoculation of young plants resulted in the highest infection percentages. Tuber size and
yield were negatively affected by higher percentages of leafroll regardless of the stage of growth at inoculation. DTBA is best used for
detecting PLRV in foliage of plants grown from infected tubers (i.e. secondary PLRV). DTBA is less accurate for detecting primary PLRV.
Wicks, TJ, CW Davoren and BH Hall. "Fungicidal control of Phytophthora erythroseptica: the cause
of pink rot on potato." [Vol. 77, No. 4, 233-240]
Two shade house and six field experiments were undertaken to evaluate fungicides and timing of application for the control of pink rot of
potatoes caused by Phytophthora erythroseptica. Pink rot developed in up to 60% of tubers grown in artificially inoculated soil and
21% of the tubers in naturally infected soil. Ridomil (metalayl) and Ridomil Gold (mefenoxan) granules applied to the soil at planting
completely or nearly completely controlled pink rot throughout the season in both pot and field experiments. Foliar applications of Ridomil
Gold MZ (mefonoxan plus mancozeb) applied when tubers were around 20 mm diameter and another one or two sprays 12 to 28 days
later also provided more than 80% control of pink rot in most experiments. Foliar applications of Shirlan (fluazanim) or Acrobat MZ
(dimethomorph plus mancozeb) showed some activity against pink rot, but were significantly less effective than Ridomil Gold MZ.
Foli-R-Fos 200 (phosphonic acid) or Dithane M45 (mancozeb) applied to the canopy showed little activity against pink rot in most
experiments. Yield increases of between 6 and 17 tons ha4 resulted from the application of either Ridomil granules at planting or two to
three Ridomil Gold MZ foliar sprays around "tuber set."
Yencho, G Craig, Stanley P Kowalski, George G Kennedy and Lind L Sanford. "Segregation of
leptine glycoalkaloids and resistance to Colorado potato beetle (Leptinotarsa decemlineata (Say)) in F2 Solanum tuberosum (4x) x
S. chacoense (4x) Potato Progenies." [Vol. 77, No. 3, 167-178]
Solanum chacoense Bitter is resistant to the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say). Resistance
has been associated with the presence of a rare class of glycoalkaloids, the leptines. In this study, seven tetraploid, F2 S. tuberosum
x S. chacoense families were evaluated for foliar production of leptines I and II, leptinines I and II, and a-solanine and
a-chaconine; and screened for resistance to CPB in the laboratory and field. Resistance was correlated with the concentrations of
glycoalkaloids on a family and an individual basis. Leptine concentrations ranged from undetectable to a high of 18.0 mg/g dry weight.
All of the progeny produced solanine and chaconine. Family 9263 had the highest mean leptine concentration and the
lowest mean leaf disk feeding and CPB defoliation levels. Family 9616 had the lowest mean glycoalkaloid concentration and ranked as one
of the most susceptible families. Regression analyses of solanine + chaconine, leptine I and II, and leptinine I and II foliar
concentrations versus leaf disk consumption and field defoliation revealed that only increased foliar levels of leptines resulted in
decreased CPB feeding. The regression models for leptines versus leaf disk consumption and field defoliation were highly significant,
accounting for 17% and 26% of the variation in consumption and defoliation, respectively. To the best of our knowledge, this is the
first work reporting the impact of leptine and leptinine concentrations on CPB feeding in tetraploid. S. tuberosum x
S. chacoense potato hybrids. Results are discussed within the context of breeding for resistance to CPB.