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1.
Summary In a glasshouse experiment three potato cultivars were grown to maturity in wet or dry compost. The number of lenticels per
tuber was greater with larger tubers but was unaffected by the cultivar or soil moisture regime. The frequency of lenticel
penetration by a water soluble stain, safranin O, remained high as tubers developed to maturity in wet soil. In dry soil penetration
declined markedly as the tubers matured. When tubers, harvested just before the onset of haulm senescence, were inoculated
withErwinia carotovora ssp.atroseptica, the frequency of lenticel rotting was less than the rate of stain penetration, indicating that additional factors were involved
in the bacterial infection process. Inoculating mature tubers with bacteria and incubating them in anaerobic conditions frequently
resulted in rotting of the lenticels. Comparable tubers incubated in aerobic conditions showed no rotting or invasion by bacteria.
The results are discussed in relation to the biological control of blackleg. 相似文献
2.
Summary Over 2 years, seed tubers or stems were inoculated withFusarium sulphureum Schlecht. (F. sambucinum Fuckel f. 6 Wollenw.) and the incidence of dry rot on daughter tubers assessed by standardised wound tests. The amount of
stem and soil inoculum was also measured in one year.
Inoculating stem bases resulted in greater concentrations of spores on the stem bases, greater soil populations at harvest
and more dry rot on tubers than inoculating the seed tuber. Overall, the incidence of dry rot and the amount of stem and soil
inoculum was similar for the three methods of haulm destruction: cutting and removing the stems, applying sulphuric acid or
applying diquat dibromide to the growing plants. 相似文献
3.
Summary 23 potato cultivars were grown in fields infested with potato mop-top virus and spraing was assessed on tubers at harvest
and after storage. Large differences in spraing susceptibility were found between cultivars. Compared with other countries,
spraing in Denmark is characterised by a high incidence at harvest, a low increase during storage and a very low proportion
of superficial spraing. Decrease in spraing during storage was recorded in two cultivars. DASELISA tests for PMTV in tubers
revealted a high reliability. Mapping of PMTV in important Danish potato growing areas showed that the virus is widespread.
Occurrence of spraing did not influence total yield or dry matter content. Soil acidity did not influence incidence of spraing
but it was more common on coarse-grained soil than on finer sandy soils. PMTV in viruliferous resting spores ofSpongospora subterranea was inactivated by heating to 90°C for 15 minutes. 相似文献
4.
K. Scholte 《Potato Research》1989,32(3):367-376
Summary The effects of soil-borneRhizoctonia solani on yield and quality of potato were studied by an extensive individual plant sampling procedure. From 1983 to 1986, stem
canker and stolon pruning were examined in 10 768 plants growing on a sandy soil. Tuber yield and quality and haulm yield
per plant were also recorded.
The degree of attack byR. solani depended on the cropping frequency of potato. Severe and very severe stem and stolon attacks decreased fresh yield, dry matter
yield and dry matter content of tubers and increased the number of deformed and small tubers, whereas the effect on haulm
yield and stem number was small.
Potato cultivars differed in susceptibility toR. solani, but yield response did not differ significantly between cultivars at the same levels of stem and stolon infection. 相似文献
5.
S. F. Carnegie P. T. Gans G. J. Jellis G. Little C. Logan R. L. Wastie 《Potato Research》1989,32(3):301-309
Summary Undamaged and damaged tubers of 10 cultivars were inoculated withPhoma foveata by two methods at five test centres over three years. Damaging tubers before inoculation increased the discrimination between
cultivars. While this increase was small with tubers rolled in cornmealsand cultures, it was often substantial with those
dipped in a suspension of comminuted agar cultures. Correlations between centres for the four tests were significant (P<0.05) and were highest for tubers inoculated with cornmeal-sand with or without damage. The gangrene scores of the cultivars
in the four tests were correlated (P<0.05) with their field susceptibility ratings but there was a strong interaction between cultivar reaction and year of test.
When tubers grown in Cumbria and Midlothian were tested at one centre over two years, the gangrene scores were also correlated
(P<0.05). 相似文献
6.
D. C. E. Wurr C. C. Hole Jane R. Fellows Jane Milling J. R. Lynn P. J. O'Brien 《Potato Research》1997,40(3):297-306
Summary Five experiments studied the effects of shading, temperature and stolon growth medium on stolon and tuber formation. The lowest
numbers of stolons and tubers were produced at the higher and lower nodes. Numbers of primary stolons and tubers were relatively
stable across nodes and treatments and variation in total numbers was largely due to changes in numbers of lateral and branch
stolons. In the field, 70% shading reduced numbers of stolons and tubers by reducing lateral and branch stolons, while in
hydroponics, 45% shading and temperatures at initiation had no effect on tuber numbers. In both environments later planting
tended to reduce numbers of stolons and tubers. There were large effects of the physical environment, with compost producing
three times as many tubers as dry vermiculite. The potential number of tubers may be determined by the number of stolons and
the environmental conditions affecting stolon formation and development. 相似文献
7.
Summary
Solanum tuberosum potato cultivars with differing levels of resistance to dry rot caused byFusarium sulphureum were hybridised in a half diallel crossing programme. Glasshouse grown tubers from true seedlings and field-grown tubers
of the resulting progenies were assessed for their resistance toF. sulphureum. Statistical analysis revealed differences between the progenies forF. sulphureum resistance on both field and glasshouse grown tubers. On the field grown tubers, differences between progenies were due to
differences in the general combining ability (GCA) of the parents. Parental phenotypes and GCA values were highly correlated.
Overall. GCA was consistent for resistance or susceptibility, and glasshouse grown progenies showed a good correlation for
GCA between years (r=0.85***), and with the results of the field grown progenies (r=0.61* in 1998 and r=0.69** in 1999). It appears that resistance toF. sulphureum is heritable, and that this heritability is better assessed on field grown rather than glasshouse grown tubers, although
the two are largely in agreement. 相似文献
8.
Ulla Bång 《Potato Research》1992,35(1):3-15
Summary In each of the five years 1978 to 1982, seed lots of cv. Bintje, variously infested byPhoma foveata Foister andFusarium solani var.coeruleum (Sacc.) Booth, as found by wound and cut tests, respectively, were planted in a series of field experiments at six sites
in Sweden. A statistically significant relationship between seed and progeny infestation was found forP. foveata each year, and in three years forF. solani.
Benomyl and thiabendazole mist treatments of seed tubers at grading in spring controlled the development of gangrene and dry
rot in treated seed tubers, but did not consistently reduce the levels ofP. foveata andF. solani infestation in progeny from treated seed tubers.
The site of cultivation markedly influenced mean levels ofP. foveata infestation, which were found to be related to temperature and rainfall during a 40 day pre-harvest period at the trail sites;
however, mean levels ofF. solani infestation were not so related. 相似文献
9.
Summary The resistance to gangrene (caused byPhoma exigua var.foveata) of progenies from two hybridisation schedules involving cultivars resistant, susceptible, or of intermediate reaction to
gangrene was assessed. Two methods of sampling tubers from field-grown single-plant plots of 18 clones representing each progeny
were used: one tuber was taken from each plant, and a bulk sample of 18 tubers was selected at random from the whole progeny.
Gangrene resistance was assessed after incubating tubers which had been rolled in cornmeal-sand inoculum ofP. exigua var.foveata, and was expressed as a percentage of tubers infected. Results from the two methods of sampling correlated closely, and agreed
well with tests in a subsequent year on 10-tuber samples of each individual clone.
It is concluded that an 18-clone sample adequately represented each progeny, and that the mid-parent gangrene score satisfactorily
predicted the resistance of the resulting progeny. There are indications that susceptibility tended to be dominant. The implication
of these findings to breeding for resistance to gangrene is discussed. 相似文献
10.
Slug damage and control of field slug (Deroceras reticulatum (Müller)) by carvone in stored potatoes
Summary After a wet autumn and harvesting under wet conditions, slugs brought into potato stores via clods and soil adhering to tubers
may cause substantial damage by feeding on the tubers.
A carvone sprout inhibitor, Talent?, applied in the potato stores at a dose of 50 ml per tonne potatoes, controlled slugs within a few days. A dose of 25 ml
carvone was insufficient. Using a laboratory box test, the slug (Deroceras reticulatum) affected only wounded tubers and, although slime was present on the unwounded potatoes, they were not damaged by slugs. 相似文献
11.
Summary The majority of isolates ofFusarium avenaceum caused dry rot on potato tubers; many were as pathogenic asF. coeruleum. Pathogenicity ofF. avenaceum was not related to the plant species from which the isolates originated. Tubers of potato cv. Cara were more susceptible
than those of cvs Romano or Maris Piper. Temperature (5–15° C) had no effect on lesion depth but lesions tended to be slightly
wider at the lowest temperature. Two isolates (of 61) from wheat and white lupin had a moderate level of resistance to thiabendazole.
The results are discussed in relation to the control of dry rot in stored potato tubers. 相似文献
12.
J. P. D. Wanasundera G. Ravindran 《Plant foods for human nutrition (Dordrecht, Netherlands)》1994,46(1):33-39
The nutrient and antinutrient components of tubers from seven cultivars ofDioscorea alata were determined. The average crude protein content ofD. alata tubers was 7.4%. Starch (75.6–84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13.0 to 24.7 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58.6 to 198.0 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486–781 mg/100 g dry matter, but may not constitute a nutritional concern since 50–75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops. 相似文献
13.
Summary A study was carried out on eightF. oxysporum f.sp.tuberosi isolates from northern Italy. Six were from rotten tubers and two were from weak, but not wilted plants from seed-growing
areas. Greenhouse and laboratory tests were done to assess the pathogenicity and potential spread of the fungus within the
plant. All isolates caused dry rot on inoculated tubers. They were also able to infect vascular tissues through roots and
leaves, but none caused wilt, stemend rot or other symptoms.F. oxysporum is often not visible in the field, but its propagules can increase under favourable conditions. It may therefore become a
potential danger during potato storage. 相似文献
14.
Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive.
Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated
seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk.
Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than
in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d. 相似文献
15.
Summary Using the fluorescent lipid stain fluorol yellow 088 to detect suberin in tubers, the numbers of layers and the thickness
of the suberized cells in the periderm and within the lenticels showed changes after the early stage of tuber formation. These
changes as tubers matured were affected by cultivar and soil moisture conditions. Penetration of the surface tissues of tubers
by the water soluble stain safranin O was confined to the lenticles. Although the zone of suberized cells in lenticels acted
to some extent as a barrier to penetration, there was not a clear relationship between permeability and suberization. Stored
tubers showed thicker suberin berriers in lenticels than freshly harvested tubers. When lenticels of stored tubers proliferated
the suberin barrier was disrupted but a further thick suberin barrier formed after exposure to air for two weeks. The findings
are discussed in relation to biological control ofErwinia by antagonistic bacteria. 相似文献
16.
C. B. Wegener 《Potato Research》2001,44(4):401-410
Summary Four potato lines of cv. Désirée that express the pectate lyase (PL) isoenzyme 3 ofErwinia carotovora subsp.atroseptica were examined in a 4-year field experiment with respect to plant development, tuber yield and resistance of tuber tissue
toErwinia soft rot. The PL3 degrades plant cell wall pectin into unsaturated oligogalacturonates eliciting plant defence responses.
In one line, enzyme expression was controlled by the CaMV 35S promoter (C) and in three lines it was driven by the potato
patatin B33 promoter (D). Plant development of the D-lines in field plots was not distinguishable from that of the non-transgenic
counterpart. Also tuber yield was not too different. By contrast, plants of the C-line were smaller than those of the nontransformed
counterpart and also showed reduced tuber yield. There were no significant differences in dry mass, starch and protein content
of tuber tissue between PL transgenic and non-transgenic potatoes. But compared with the latter, field-grown tubers expressing
the PL displayed an enhanced resistance toErwinia soft rot. Thus, average rotting caused byEc-bacteria was diminished in tubers of PL-transgenic lines by 34.1%. The resistance of tubers toEc soft rot was significantly correlated with the PPO activity in tuber tissue. 相似文献
17.
K. Mansfeld-Giese 《Potato Research》1997,40(2):229-235
Summary Plant-to-plant transmission of the bacterial ring rot (BRR) pathogen,Clavibacter michiganensis subsp.sepedonicus (Spieck. et Kott.) Skapt. et Burkh. of potato (Solanum tuberosum L.), was studied in field trials over a three year period. Healthy and infected seed tubers were planted 35 cm apart. In
one treatment, a subsurface barrier was placed between the healthy and infected seed tubers separating the root systems of
neighbouring plants. In this treatment, none of 216 plants grown from healthy seed tubers was infected at harvest, as determined
by indirect immunofluorescence antibody staining (IFAS) with monoclonal antibodies. In the other treatment, no subsurface
barrier was used. In this treatment, two of 368 plants (0.5%) grown from healthy seed tubers were infected at harvest. It
is concluded that plant-to-plant transmission may occur but at very low frequency, and is unlikely to play a significant role
compared with the potential of transmission by shared potato handling equipment. 相似文献
18.
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
19.
Summary This paper reports results of a 3-year evaluation of CIP advanced potato clones in a bacterial wilt-infested field (race 3)
in Peru. Clones resistant or moderately resistant to wilt were selected and all tubers harvested from each clone were tested
for latent infection byRalstonia solanacearum using a sensitive serological technique developed at CIP. A sampling strategy to estimate accurately the frequency of infected
tubers in the clones has been evaluated. This method will allow consideration of tuber latent infection as a new selection
criterion in breeding for resistance to bacterial wilt. Thirteen clones were found resistant to wilt in all three evaluations
(i.e.≤6% wilt), from which five had no wilt in all trials. However, all clones harboured latent infection in tubers averaging
30%. Analysing 30 tubers/clone provides an accurate estimation of the proportion of infected tubers with a high precision
level. 相似文献
20.
Summary The effect of water stress on yielding capacity of potatoes was studied in 3 years using four different levels of soil water
potential (0.7, 1.9, 3.4 and 7.8 atm.) in experiments in specially adapted structures that excluded uncontrolled water supply.
Seed tubers from these crops were planted in the following years to investigate effects of water stress on their subsequent
performance.
Limited soil moisture availability decreased yield and the number and size of tubers. The growing period was shortened by
1–4 weeks and dormancy period by 2–8 weeks. In the following year, seed produced under conditions of moisture stress gave
plants with 20% fewer stems. 24–33% less yield, 18–22% fewer tubers and 19–22% fewer large tubers than plants from seed produced
under abundant water supply. It is concluded that the yield potential of seed tubers can be improved by careful attention
to the availability of soil moisture during their production. 相似文献