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1.
Summary Potatoes were stored in three insulated bins having ventilation rates of 0.0190, 0.0306 and 0.0417 m3/s·t. The results showed that in the climate of northern Italy potatoes can be stored successfully at ventilation rates of
not less than 0.0306 m3/s·t resulting in product weight loss of less than 2.0% after 100 days' storage. The incidence of diseases and of sprouting
was very low at rates of 0.0306 and 0.0417 m3/s·t, but greater at 0.019 m3/s·t because of the higher tuber temperature. Laboratory tests simulating ambient conditions confirmed the validity of a thermodynamic
model simulating air-potato heat exchange. 相似文献
2.
Summary A heat balance method for measuring sap flow in actively growing plants was tested on three potato (Solanum tuberosum L.) cultivars Monona, Norchip and Atlantic. The method is based on applying a known heat source to the stem of an intact
plant: by measuring the axial and radial heat dissipation the magnitude of sap flow can be quantified. The technique shows
promise as 24 h accumulated sap flow measurements were highly correlated (r2=0.935, n=36) with gravimetric measurements of transpiration and produced an average root mean square error (RMSE) of 20 g
d−1. The accuracy of the method improved as daily accumulated flow increased. Under low daily flow rates overall RMSE increased,
supporting the need for a heat storage term in the heat balance equation. Short term flow rates were less significantly correlated
(r2=0.764, n=1572) and produced an average RMSE of 2.89 g h−1. Identification of these short term flow rates during high flow periods may be difficult. The presence of water potential
gradients and the likelihood of re-hydration during high flow events may have also affected the short term performance of
the method. At low flow rates, many different errors may be introduced. 相似文献
3.
Summary Twenty seven cultivars of potato were screened for common scab grown in a commercial field in two successive years (1996–97
and 1997–98). Eight cultivars were least susceptible and the others ranged from medium susceptible to very highly susceptible.
None of the cultivars was resistant. Most showed a stable resistance reaction in both years. 相似文献
4.
Effect of haulm treatments on the formation of microsclerotia ofVerticillium dahliae Kleb. on potato
Summary In four pot experiments, potato plants of cv. Element were artificially infected withV. dahliae. At an early and a late harvest haulms were killed chemically, by burning or by various other treatments, including cutting
them into pieces of different lengths and keeping the debris on the soil surface or covering with soil. After 4 weeks the
plant material was air-dried and the number of microsclerotia per mg was determined.
At the early harvest, in two experiments, the chemical treatment yielded more microsclerotia than the cutting treatments.
Covering colonised haulm tissue with non-sterilised soil was effective in inhibiting microsclerotia formation. Shorter haulm
pieces led to fewer microsclerotia at the later harvest if the material was kept on the soil surface. The variation in microsclerotial
yield and in treatment effects among the different experiments was large. 相似文献
5.
Summary A sensitive, rapid and inexpensive method has been developed for quantifying the glucose, fructose and sucrose content of
potato tubers. The method, based on selective enzyme-coupled reaction systems and the reduction of NAD to NADH, uses a microplate
reader fitted with a 340 nm filter. In one microtiter plate 96 samples can be analysed for all three sugars in less than two
hours. Several plates can be processed in parallel. 相似文献
6.
Relationships between ground cover,intercepted solar radiation,leaf area index and infrared reflectance of potato crops 总被引:2,自引:0,他引:2
Summary In field trials with potato several methods determining the proportion of intercepted solar radiation by the crop were compared.
Non-destructive measurement of the proportion of ground cover with the aid of a grid correlated well with the proportion of
intercepted photosynthetically active radiation as measured with a tube solarimeter and with the leaf area index. Measurement
of the infrared reflectance of the crop proved to be an efficient and objective method to show differences between treatments.
Moreover, it showed a good correlation with ground cover and radiation interception until full closure of the canopy. Percentage
ground cover is useful for assessing intercepted solar radiation and leads to fewer errors in calculation of efficiency of
conversion into dry matter than the other methods. 相似文献
7.
Summary
Phytophthora infestans isolates collected in Poland in 1987–1995 were evaluated on detached leaflets of a differential series consisting of potato
genotypes possessing resistance genes R1–R11. On the same differentials was evaluated over three years a highly virulentP. infestans isolate MP 245.
Isolate MP 245 and those from natural populations ofP. infestans were seldom or inconsistently pathogenic to R5, R8 and R9. When leaflets of the differentials were infected with MP 245 the
lesions were often small and sporulation weak. A statistically significant interaction was found between years and pathogenicity
of MP 245 to individual differentials. Attempts to train the isolate MP 245 for pathogenicity to R9 were unsuccessful.
The variation in specific resistance of potato genotypes may complicate the evaluation of their resistance toP. infestans, as well as the evaluation of the virulence spectrum of natural fungus populations. This variation may be due to changes
in specific pathogenicity of the fungus or in specific resistance of the potato. Some differentials have a possibly useful
resistance toP. infestans. 相似文献
8.
A comparative study of phenylpropanoid metabolism in gamma irradiated and unirradiated potato tubers
Summary Phenylpropanoid metabolism in gamma irradiated potato tubers was studied by examining the pattern of incorporation of radioactivity
from U-14C phenylalanine into caffeic acid. chlorogenic acid and the coniferyl and sinapyl moieties of lignin. During a post-irradiation
period of 21 days a depletion in chlorogenic acid was observed. This is a result of its impaired synthesis as well as an accelerated
conversion of chlorogenic acid to ferulic and sinapic acids and their deposition in lignin.
The results offer an explanation for the lower level of chlorogenic acid invariably observed in irradiated potato tubers. 相似文献
9.
10.
Mairi L. Vernon-Shirley Robert Burns Edna L. George Margaret E. Hoadley 《Potato Research》1993,36(2):83-88
Summary Two monoclonal antibodies (McAbs) which react specifically with potato virus T (PVT) were produced and tested for cross reactivity
with potato viruses (A, S, X, Yo, YN, leaf roll), apple stem grooving virus (ASGV) and against healthy sap. They were found to be highly specific for PVT. These
two McAbs form the basis of an enzyme-linked immunosorbent assay (ELISA) for the detection of PVT in infected plant material
which is of key significance for potato quarantine. 相似文献
11.
C. M. Menzel 《Potato Research》1985,28(2):263-266
Summary In potato (Solanum tuberosum L., cv. Sebago), benzyladenine (BA) promoted tuberization at high day/night temperatures (32°/18°C), while gibberrellic acid
(GA) and chlorethylphosphonic acid (CEPA) reduced tuberization at low day/night temperatures (22°/18°C). These results are
consistent with the hypothesis that temperature exerts its influence on tuber formation by altering the balance between endogenous
gibberellins, cytokinins and inhibitors, but not ethylene. 相似文献
12.
Summary A method for assessing the leaf area of potato plants was based on the number of leaves coinciding with imaginary vertical
lines descending from a horizontal grid of points above the plant or crop canopy. Leaves seen through each vertically aligned
pair of holes in a perforated double table, covering the midpoint of the exposed area, were counted and moved aside one by
one, until the ground was seen. For both green and diseased surfaces the leaf area, or its horizontal component, was calculated
as the product of sum of records and the grid cell size. Tested against a destructive method, the technique worked equally
well for healthy and diseased leaf area of potato plants infected byPhytophthora infestans. The theoretic estimate of the standard error for a single measurement was derived as the geometric mean of the leaf area
and the grid cell size. The method is also suitable forLAI of crop stands. 相似文献
13.
Summary Potato cultivars were grown in a glasshouse and plants periodically transferred to a growth chamber. When the ambient temperature
in the growth chamber was raised from 15 to 40°C in steps of 5°C per hour, net photosynthetic rate decreased at temperatures
above 20°C. At 40°C the rate was 37% of the rate at 20°C. A greater decrease in net photosynthetic rate occurred with plants
of the cultivar Up-to-Date than with cultivars R100 and BP13. Low values of leaf diffusive resistance were recorded and changes
in photosynthetic rate could not be explained by changes in this factor. When a constant ambient air temperature of 20°C was
maintained while soil temperature was increased, net photosynthetic rate decreased. 相似文献
14.
Summary Ancymidol-induced in vitro tuberisation under different photoperiodic regimes (dark, SD=8 h, LD=16 h) and sucrose concentrations (2, 4, 6 and 8%) in cv. Jaerla (early) and cv. Baraka (late) was studied. Tuberisation was scored after 4 (dark) or 8 (light) weeks. Ancymidol significantly increased tuberisation under LD-SD for any sucrose concentration in both cultivars. Ancymidol also significantly increased tuberisation under LD-dark for 6% sucrose in both cultivars. Tuberisation in cv. Jaerla was significantly higher than in cv. Baraka for any photoperiodic treatment in the presence or absence of ancymidol with 4, 6 or 8% sucrose. The photoperiod SD-SD resulted in the higher level of tuberisation for any combination of sucrose, cultivar and ancymidol. The possible role of ancymidol is discussed. 相似文献
15.
Summary The influence of freeze dried potato powder derived from tubers (cvs Désirée and Epicure) exposed to light as a culture medium
on the growth, number and spore size of nine fungal pathogens was determined in vitro with particular emphasis on the role
of glycoalkaloids. Greater reductions in pathogen growth reflected increased exposure to light of tubers prior to freeze drying.
High correlations (% R2 adj) were obtained between glycoalkaloid concentration and growth rate of the majority of pathogens tested. Where spores
were produced, numbers were in general significantly less when cultured on freeze dried powder derived from tubers exposed
to light. No effects on spore size ofFusarium species were recorded, but spore length of remaining pathogens was reduced and spore width increased, with the exception
ofC. coccodes where spore length and width was increased following culture onto freeze dried powder derived from tubers exposed to light. 相似文献
16.
Summary Using potato parental lines homozygous at a locus or loci controlling resistance to potato leafroll virus (PLRV) can give
advantages in the selection of resistant forms. In order to identify homozygous diploid clones their test-cross families were
evaluated. All the clones that were test-crossed expressed resistance in primarily- and secondarily-infected plants and etiolated
sprouts, and were derived from mating genotypes highly resistant to PLRV. Genotypes from test-cross families varied in resistance
to PLRV, and one family was found which had only resistant genotypes, suggesting that the resistant parent of this progeny
was homozygous at resistance loci. Evidence was gathered that resistance in some diploid clones may result from resistance
to virus multiplication as well as restricted virus transport from leaves to tubers. 相似文献
17.
Summary In 1983 and 1984 there were reports in Norway of more severe late blight infection than usual on tubers of cv. Pimpernel,
a cultivar without R-genes known to be somewhat resistant to both haulm and tuber infection. Results from routine tests confirmed
earlier experience that cv. Pimpernel shows stable resistance to tuber late blight, although the ranking of cultivars may
vary between years.
In experiments during three harvest seasons tubers of different cultivars were inoculated with isolates ofP. infestans obtained from stocks of cv. Pimpernel with severe tuber late blight and with other isolates. In these experiments the isolates
from cv. Pimpernel caused more rot on tubers of Pimpernel than did other isolates. 相似文献
18.
Summary The relationships between the number of initial sprouts, the number of main stems, stolons and tubers per plant are depicted
in 4-quadrant figures. The number of sprouts per seed tuber varied because of different pre-sprouting conditions and/or because
of the use of different cultivars. Good linear relationships are shown between the numbers of sprouts and stems, stolons and
tubers, and sprouts and tubers, but especially between stolons and tubers within each trial with the one cultivar. When comparing
different experiments with the one cultivar the linear relationship between the numbers of stems and stolons disappeared.
When comparing different cultivars, no relation was found between the numbers of sprouts and stems. These two cases also led
to a statistically less significant relation between the number of sprouts planted and the number of tubers harvested. 相似文献
19.
Bacillus thuringiensis cry1Ab gene confers resistance to potato againstHelicoverpa armigera (Hubner)
S. K. Chakrabarti A. D. Mandaokar A. Shukla D. Pattanayak P. S. Naik R. P. Sharma P. A. Kumar 《Potato Research》2000,43(2):143-152
Summary
Helicoverpa armigera is one of the important insect pests adversely affecting the yield of potatoes in India. A synthetic gene encoding the insecticidal
crystal protein (Cry1Ab) ofBacillus thuringiensis (Bt) has been introduced into five genotypes of potato usingAgrobacterium tumefaciens. Southern analysis of DNA from transgenic plants confirmed the integration and copy number of the transgene. Double-antibody
quantitative sandwich ELISA analysis demonstrated high levels of Cry1Ab protein expression in transgenic plants. Insect bioassays
on the leaves of transgenic plants showed considerable protection against the larvae ofH. armigera in terms of leaf area consumed and larval weight reduction. 相似文献
20.
Summary The susceptibility of 21 potato cultivars to leak (watery wound rot) caused byPythium aphanidermatum was compared. Whole tubers were inoculated after wounding by dipping into a water suspension of 103 oospores/ml and incubated for 3 days at 25°C. The mean penetration of tissue calculated from the recording of lesion width
and depth and the qualitative assessment of rot extension were highly correlated. For 10 of 12 cultivars tested at least twice,
consistent reactions were obtained: cvs Korrigane. Superstar, Safrane and Yesmina were moderately susceptible, whereas Atlas,
Diamant, Mondial, Obélix, Spunta and Timate were susceptible to highly susceptible. Tubers originated from two locations and/or
two cropping seasons: thus, the performance of these cultivars under different production conditions reveals a satisfactory
level of agreement with the test. Moreover, ratings assigned are supported by field or store observations. 相似文献