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1.
Jemseg is an early sizing variety of early maturity. It has outyielded the variety Warba for total and marketable yield when dug at 80 days from planting. It has moderate resistance to common scab, is immune to virus X and has high resistance to virus Y, plus resistance to virus S. Jemseg was originated at Fredericton, New Brunswick, and is a product of the potato breeding program of Agriculture Canada. The variety has been under test in New Brunswick for 10 years as seedling F67072. It has also been tested extensively in the Maritime Provinces and throughout Canada through the facilities of regional and national evaluation trials. Jemseg was selected from a progeny of a cross between the variety Sable and a Fredericton seedling F55069. Sable is an early variety developed at Fredericton. F55069 is a Fredericton seedling bred for X immunity and scab resistance. Jemseg was first grown in the field in 1967. The pedigree follows: 相似文献
2.
Tobique is a chipping variety with good yield and table quality. It is resistant to Verticillium wilt,Fusarium sambucinum, Fusarium coeruleum, and virus Y. Tobique was originated at Fredericton, New Brunswick and is a product of the potato breeding program of Agriculture Canada. This variety has been under test in New Brunswick for fifteen years as seedling F61025. It has also been tested extensively in the Maritime Provinces and throughout Canada through the facilities of regional and national evaluation trials. Tobique was selected from a cross between the variety Cariboo and Fredericton seedling F45019. Cariboo was introduced in British Columbia as a maincrop variety of distinctive appearance and bruise resistance; also with resistance toVerticillium alboatrum andPhoma rot. F45019 is a late blight resistant seedling with high dry matter. Pedigree: {ie419-01} 相似文献
3.
Russet Burbank and Shepody potatoes were grown with at-planting nitrogen fertilizer rates varying from 0 to 270 kg ha?1 following small grains and red clover. Petiole samples were collected from the 4th and 5th leaflets at four to six dates each during the 1986 to 1989 growing seasons. The samples were dried and analyzed for NO 3 ? N content. Petiole NO 3 ? N levels were strongly related to nitrogen rate regardless of cultivar, growing season, and cropping system. Differences among treatments and NO 3 ? N content varied substantially as the growing season progressed with petiole NO 3 ? N levels declining rapidly in underfertilized plots as the plants aged. Petiole NO 3 ? N levels were higher at midseason following red clover than following small grains. Sampling 50 to 60 days after planting (DAP) is most appropriate as a tool for scheduling supplemental nitrogen applications. At 50 DAP, critical petiole NO 3 ? N levels were 1.6 and 1.7% for Russet Burbank and Shepody, respectively. Petiole NO 3 ? N levels above 2.2% at 50 DAP resulted in lower yields of Russet Burbank than when petiole NO 3 ? N levels were in the 1.6 to 2.2% range. Petiole NO 3 ? N testing should be particularly useful as a diagnostic tool in management strategies which make maximum use of previous crop residues, organic amendments, and soil reserves as nitrogen sources. 相似文献
4.
Variation in resistance to tuber damage by the tobacco flea beetle,Epitrix hirtipennis (Melsheimer) was investigated for progeny from a group of parental clones from the USDA potato breeding program. Each of nine clones, used as males, was crossed with three different clones, and the family responses were measured in field tests (Lubbock, Texas, 1967 and 1968) by counting tuber pits made by the flea beetle larvae. Statistically significant differences among families were found. The differences were due mainly to the male parents, since the male variance component, σ M 2 (0.470±0.235), was larger than the variance component of females mated to the same male, σ F(M) 2 (0.080±0.057). Theoretically, each of these components contains one-fourth of the genetic additive variance, and therefore, should be nearly equal if digenic, trigenic, and quadrigenic effects are small (and if no maternal effects are present). Apparently the male and female parents did not, in relation to the frequency of alleles controlling response to the flea beetle, represent the same genetic population. Heritability on an individual basis, calculated with 4 σ M 2 as numerator, equals 0.64±0.36; and at a 10% selection level the genetic advance value predicted for individual selection equals 1.896 SD units. If 100 males were crossed to one female each, and 20 progeny per family tested in 10 replicates, the genetic advance value predicted for selecting the best 10 males on the basis of their family performance equals 0.976 SD units. Thus individual or phenotypic selection appears to be more effective than selection based on half-sib progeny tests. 相似文献
5.
Models which simulate the development of potato early blight, potato late blight and fungicide dynamics were used to analyze the effects of host resistance, fungicide and weather on individual and combined epidemics of these diseases. Fungicide and host resistance effects were based on (and accurately reflected) products and cultivars available to commercial potato growers in northeastern USA. Moderate resistance to early blight had a 2-3 fold greater effect than did moderate resistance to late blight in suppressing early and late blight, respectively. Analysis of simulation experiments indicated that replacement of an early blight susceptible cultivar with a cultivar moderately resistant to the disease would permit a reduction in the fungicide application frequency from once every week to once every two weeks without loss of disease suppression. Fungicide effect in suppressing late blight was 2-3 fold greater than in suppressing early blight. Variation in seasonal weather (typical of northeastern USA) influenced late blight development more strongly than it affected early blight development, and it affected epidemics of individual diseases more than combined epidemics. 相似文献
6.
W. C. James C. S. Shih W. A. Hodgson L. C. Callbeck 《American Journal of Potato Research》1973,50(1):19-23
A regression analysis was used to develop a method to estimate the decrease in marketable tubers caused by late blight of potato (Phytophthora infestans), based on estimates of percentage loss in total tuber yield computed from a published method. The economic loss due to late blight in table stocks is the relative percentage marketable yield loss, calculated from the expression: {fx19-01} when total yield losses (in percentage) did not exceed 40%. A graphical method is presented as an alternative. Yield results from seven field experiments conducted in the Maritime Provinces of Canada during the period 1953 to 1971 were used in the study, where marketable tubers were defined as 2 1/4 inch or more in diameter. 相似文献
7.
A linear polynomial model is presented $$Y = \beta _0 + \beta _1 X_1 + \beta _2 X_2 + \beta _3 X_3 + \xi $$ where Y = plant yield of tubers > 1 cm diameter, X1 = revised growing degree days $$\begin{gathered} RGDD = \frac{{max temp \left( { \leqslant 30^ \circ C} \right) + \min temp \left( { \geqslant 4.4^ \circ C} \right)}}{2} - 4.4^ \circ C \hfill \\ - \frac{{min temp \left( { > 4.4^ \circ C} \right) - 4.4^ \circ C}}{2} \hfill \\ \end{gathered} $$ X2 = total insolation in cal cm-2 at 350 to 1150 nm and X3 = mean daily air temperature range in °C. The β0 and ξ, (Y intercept and error term) and β1, β2 and β3 coefficients are derived from fitting the experimental data. The model was developed by growing ‘Kennebec’ in large containers at sites ranging from 1533 m to 3198 m elevation under shaded (48% insolation reduction) and unshaded conditions at 39° to 41° N latitude. Mean maximum and minimum temperatures and insolation ranged from 29°C to 19°C, 14°C to 6°C, and 200 cal cm?2 day?1 to 530 cal cm2 day?1 respectively. Soil matric potential and soil fertility were not included as variables in the model since they were physically controlled. The model does not include the period from planting to emergence since environment was not permitted to vary differentially. A highly significant multiple linear model with a coefficient of determination of 0.93 was obtained. It is suggested that including the revision $$ - \frac{{min temp \left( { > 4.4^ \circ C} \right) - 4.4^ \circ C}}{2}$$ in the heat input estimation (GDD) as well as air temperature range, emphasizes the influence of respiration on productivity. The model should be tested further and adapted as a practical method for predicting potato yield under “grower” conditions. 相似文献
8.
W. C. James C. S. Shih L. C. Callbeck W. A. Hodgson 《American Journal of Potato Research》1971,48(12):457-463
A method was developed for estimating tuber yield losses caused by late blight of potato (Phytophthora infestans) (Mont.) de Bary. The method is based on yield and disease data collected for the varieties Green Mountain and Katahdin grown in eastern Canada during the period 1953–1970. The percentage yield loss can be calculated for any disease progress curve. The estimated loss was within 5% of the actual loss in nine cases out of ten. 相似文献
9.
Pre-harvest chemical applications significantly reduced populations of viableAlternaria solani spores on the soil surface in the laboratory and field and the infection of potato tubers in the field. Only formaldehyde consistently reduced spore germination and tuber infection in the laboratory and the field but Difolatan 4F, Difolatan 4F + DMSO (dimethyl-sulfoxide), Manzate D, Manzate D + DMSO and sodium hypochlorite often reduced fungus populations significantly. More work is necessary before pre-harvest chemical applications can be recommended for control of early blight tuber decay due to the variable performance of many chemicals and the relatively high cost and corrosiveness of formaldehyde, the most effective chemical in the study. 相似文献
10.
As part of a project to investigate the possibility that teratogenic factors are formed in potato tubers infected with the late blight fungus,Phytophthora infestans, a method was devised which allowed quick, efficient inoculation of large numbers of potato tubers. Tubers were placed in specially constructed trays, wounded by puncturing the periderm with flower “pin frogs”, and sprayed with a zoospore suspensionof P. infestans prepared from cultures grown on rye agar at 20C (68F) for 10 days. Approximately 95% of Katahdin and 93% of Russet Sebago tubers inoculated by this method exhibited typical late blight lesions after two weeks incubation at 20C, 80–90% RH. Eight tons of potatoes were processed in this manner. 相似文献
11.
A host resistance factor was integrated into the FAST (Forecaster ofAlternariasolani onTomatoes) system to initiate and to schedule fungicide applications for three levels of potato cultivar susceptibility while maintaining disease control and yield. Four cultivars ranging from susceptible to moderately resistant were each treated with the fungicide chlorothalonil during two field seasons. The five fungicide treatments were a 7-day schedule initiated after 50% flowering; a non-sprayed control; and three FAST application schedules based on combinations of critical levels of cumulative severity (CS, the disease severity values as a function of leaf wetness and temperature) and cumulative rating (CR, the disease rating values as a function of average temperature and hours of relative humidity greater than 90%) values. The FAST system predicted the onset of early blight and subsequent periods conducive for disease development in 1993 and 1994. There were cultivar-by-spray-schedule interactions for both disease severity and yield, suggesting that differences in early blight sus-ceptibility exist between cultivars. Use of the recommended schedules for the cultivar’s targeted level of susceptibility reduced early blight severity and minimized fungicide use while maintaining yield. These results indicate that a host-resistance factor can be incorporated into the FAST system. 相似文献
12.
D. R. Lynch C. Schaupmeyer L. M. Kawchuk T. R. Tarn B. Rex J. Holley D. Waterer J. Panford M. K. Pritchard 《American Journal of Potato Research》1994,71(6):387-393
AC Ptarmigan is an early maturing, buff skin, cream flesh potato cultivar which has good, stable chip quality and can be processed directly from the field. The cultivar has uniform attractive tubers with shallow eyes. It is moderately resistant to common scab, early blight, potato virus Y and potato leafroll virus. It is susceptible to late blight and shows clear field symptoms when infected with bacterial ring rot. 相似文献
13.
D. K. L. MacKerron 《Potato Research》2008,51(3-4):411-427
When we consider complex, multi-step processes such as crop growth or the progress of a disease then simple mathematical functions are inadequate to describe them and we generally use some kind of mathematical model. The commonest form in use is one that we call a simulation model although there are other forms of model such as Rule-based, (e.g. Gu et al. AI Appl 10:13–24, 1996), Bayesian (Gold, Plant Disease Epidemiol 4:84–122, 1989) and ‘fuzzy’ (Burrough, J Soil Sci 40:477–492, 1989), depending upon the application. Models may sometimes be combined into packages that we call decision support systems. This paper will consider simulation modelling and also the combination of complementary models. Mathematical models of the potato crop have been devised, in a range of sophistication, over a long period of years and a quite proper question is: “Where next? What are the developments that are sought or, more importantly, that are needed?” 相似文献
14.
Ammonium sulfate (AS), ammonium nitrate (AN), urea (U), and calcium nitrate (CN) were evaluated as supplemental N sources for sprinkler irrigated potatoes on a loamy sand soil by determining N source effects on potato yield, quality, recovery of applied N in tubers, and petiole NO 3 - concentration. At the N rate required to maximize yield (224 kg N/ha), 5-year average yields obtained with AS were significantly higher than those obtained using AN, U, or CN. Average total tuber yields with AS, AN, U, and CN were 59.3, 56.2, 56.5, and 54.8 Mg/ha, respectively. Yield differences between AS and AN or CN are likely due to greater N loss through leaching from the NO 3 - -containing sources. This conclusion is supported by lower petiole NO 3 - concentrations and lower recovery of applied N in tubers when AN or CN were used. Yield differences between AS and U suggest that N applied as U is more susceptible to loss than N applied as AS on the soil used in this work. The percentage of total tuber yield in the US1A quality category was not affected by N source, but the percentage of cull tubers was higher with AS than with AN or CN. Our results indicate that potato yield and N recovery can be improved by use of AS instead of U, AN, or CN for irrigated potato production on sandy soils. Potato yield, quality, and N recovery were similar when U or AN were used as supplemental N sources. 相似文献
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16.
A. F. Reeves G. A. Porter C. E. Cunningham R. J. Nickeson F. E. Manzer T. M. Work A. A. Davis E. S. Plissey 《American Journal of Potato Research》1994,71(2):89-97
Prestile is a late maturing potato variety with attractive, round to oblong, white-skinned, white-fleshed tubers with shallow eyes. Its major use is expected to be for tablestock in areas where Katahdin and Ontario are now grown. Prestile tubers are slow to sprout in storage and do not show the net necrosis caused by potato leafroll virus, but are quite susceptible to heat necrosis. This variety is immune to potato virus X, and is moderately resistant to common scab (Streptomyces scabies), verticillium wilt (Verticillium albo-atrum), and early blight (Alternaria solani). Prestile is susceptible to skinning and shatter bruise, and is difficult to kill, particularly when heavily fertilized. 相似文献
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18.
K. G. Haynes B. J. Christ D. P. Weingartner D. S. Douches C. A. Thill G. Secor W. E. Fry D. H. Lambert 《American Journal of Potato Research》2002,79(6):451-457
Changes in the oomycetePhytophthora 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. Twentytwo 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 i (1) ) and variances of the ranks (S i (2) ) 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 × 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 × 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, Nor-Donna, 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. 相似文献
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Tuber glycoalkaloid (TGA) content, leaf glycoalkaloid (LGA) content, and the level of multigenic resistance to late blight were determined for 15 potato clones. There was no association between the level of blight resistance and the TGA or LGA contents in these clones. However, TGA and LGA contents were highly correlated. The genotypic correlation coefficient between TGA and LGA contents for the 15 clones was 0.82 (SE = 0.115). TGA contents from blight-infected plants were not significantly higher than TGA contents from healthy (fungicide-protected) plants. The results indicate that breeders should be able to select for multigenic late blight resistance withohut increasing TGA contents of clones in their breeding programs. 相似文献