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1.
Willemien J. M. Lommen 《Potato Research》1993,36(4):273-282
Summary Storage losses were studied in minitubers of cvs Agria and Liseta, using five fresh weight classes (<0.50 g, 0.5–0.99 g, 1.00–1.99
g, 2.00–2.99 g, ≥3.00 g), and three successive harvests of the same plantlets. After each harvest, tubers were dired at room
temperature (1 day), curred at 18 °C (13 days) and stored at 2 °C (540 days). Two kinds of storage losses were considered:
(a) losses of entire tubers because of deterioration, and (b) fresh weight losses of the other tubers. Both kinds of losses
were higher in cv. Liseta, in tubers with lower fresh weights and in tubers from the first harvest. Almost all minitubers
≥0.5 g from later harvests and from both cultivars survived storage for 1.5 years. Deterioration occurred mainly from 6 to
12 months of storage. Tubers which deteriorated during cold storage had already shown high weight losses during curing. 相似文献
2.
Summary Minitubers of cultivars Agria and Liseta were harvested from the same plantlets on three dates. After each harvest, tubers
were dried (1 day), cured (13 days) and cold stored at 2 °C in darkness and 80 % RH. Their performance was studied 65, 128,
191, 254, 317, 380, 443, 506 and 569 days after harvest. Minitubers (1–2 g) were planted in pots and grown for 8 weeks in
a controlled environment. After 191 days of storage their growth was still extremely poor. In both cultivars, tallest plants
and largest leaf areas per plant were observed in plants from tubers from the second and third harvests that had been stored
for 317 days. Highest stem numbers, yields (total dry matter, tuber fresh weight) and harvest indices were achieved with 443
days storage with cv. Agria and 569 days storage with cv. Liseta. Tubers from the first harvest behaved slightly differently. 相似文献
3.
Willemien J. M. Lommen 《Potato Research》1993,36(4):265-272
Summary Dry-matter concentration and dormancy were studied in minitubers of cvs Agria and Liseta, using five fresh weight classes
(<0.50 g, 0.50–0.99 g, 1.00–1.99 g, 2.00–2.99 g and ≥3.00 g) and three successive harvests of the same plantlets. The average
dry-matter concentration increased with tuber weight for tubers from the second and third harvests. In minitubers ≥0.5 g,
dry-matter concentration was higher in tubers from later harvests. The dormant period (days from harvest to 50% sprouting)
was longer in minitubers with lower than higher weights, and longer in tubers from the first harvest than from later harvests.
A cold-storage period of 6 weeks, starting 14 days after harvest, reduced the dormant period by an average of 11 days. 相似文献
4.
Summary Multiplication factors and progeny yield variation in crops from minitubers of five weight classes (ranging from 0.13–0.25
g to 2.00–3.99 g) and conventional seed tubers were studied in field experiments in three years. Multiplication factors were
calculated as the number and weight of progeny tubers produced per planted tuber or per unit planted tuber weight. They were
lower for the lighter minitubers when calculated per tuber and higher when calculated per weight. Yield variation was described
by coefficients of variation for the number and weight of progeny tubers produced. Variation over individual plants of a crop
was higher in stands from the lighter minitubers. Variation over plots within a field was sometimes higher for the lighter
minitubers, but variation over years was similar for all minituber classes. Variation over plots in progeny tuber weight was
higher for minitubers than for conventional tubers. 相似文献
5.
Summary Field performance of five fresh weight classes of minitubers ranging from 0.13–0.25 g to 2.00–3.99 g and conventional seed
tubers was studied in a short growing season (79 or 82 days) in two years. The heavier minitubers gave a more regular emergence,
faster ground cover soon after emergence, higher dry-matter yields, and higher fresh tuber yields. Radiation conversion coefficient
(RCC) did not differ. Higher tuber yields resulted from more radiation intercepted due to a faster ground cover, and a higher
harvest index. All minitubers produced plants with one primary stem. In one experiment when heavier minitubers had long sprouts,
time to 50% emergence decreased with tuber weight, whereas dry-matter concentration of progeny tubers increased. Conventional
tubers appeared superior to minitubers in all characteristics mentioned except RCC, which was similar. Differences in performance
between minitubers and conventional tubers were attributed to weight and age of seed tubers, presprouting method and crop
husbandry. 相似文献
6.
Summary Large scale, commercial production of potato minitubers, cvs Spunta, Jaerla and Kennebec, has been carried out in VITRO HELLAS
S.A. since 1995, according to protocols based on in vitro methods. Apical meristems were cultured on MS medium supplemented
with 1 μM IBA, 20 g/l sucrose and 6 g/l agar (pH 5.8). Subculture was carried out every 15 days. Multiplication rate was 4–5
per cycle. Self-rooted microplants were transferred into screen houses (200 plants/m2) in a mixture of peat and perlite 1∶1 (v/v). Cultivation period was 15 August to 15 November each year. During the period
1995–1997, the number of minitubers produced/plant was 2.07 for cv. Spunta, 1.85 for cv. Jaerla and 2.52 for cv. Kennebec
and their average weights were 10.8 g, 10.9 g and 9.8 g, respectively. The percentage of minitubers<10 mm in diameter was
2%, 50.1% were 10–20 mm and 47.9% were>20 mm. 相似文献
7.
Willemien J. M. Lommen 《Potato Research》1994,37(3):315-322
Summary The behaviour of minitubers in five weight classes, having mid-point values between 0.19 and 3.00 g, was studied during sprouting
and emergence under controlled conditions. Lighter tubers took longer to produce sprouts of 2 mm, and their sprouts grew more
slowly between 2 and 4 mm and 4 and 6 mm. As sprouts lengthened their rate of growth increased. The influence of tuber weight
was less for heavier tubers and also decreased as the sprouts grew longer. When tubers with sprouts of the same length were
planted in pots, sprouts from lighter tubers took longer to emerge. Emergence was later and differences between weight classes
were larger when tubers were planted deeper (6 or 9 cm) or when they had shorter sprouts at planting (2 or 4 mm). At emergence,
plants from lighter tubers had thinner stems and lower stem and root weights, but higher stem weights proportional to tuber
weights and higher shoot:root ratios. 相似文献
8.
J. Marinus 《Potato Research》1993,36(1):55-61
Summary The formation of above-ground tubers on stem cuttings of eight potato cultivars was studied over three seasons. To promote
tuber formation in the leaf axils, stems grown from single node cuttings were exposed to short day conditions. Tuber formation
underground was reduced by covering the soil with a plastic sheet and by using single node cuttings planted with the leaf
axils several centimetres above the soil surface. With all cultivars except Alpha, which produced mis-shapen tubers in all
experiments, an average of 11 (maximum 40) tubers per cutting were harvested. Significant cultivar × year interactions were
observed. 相似文献
9.
Soile Prokkola 《Potato Research》1994,37(2):103-111
Summary Seed potatoes of cvs Record and Bintje were grown with 30, 80 or 130 kg N/ha. In the subsequent growing season the seed tubers,
which were inoculated or not with two concentrations ofErwinia carotovora subsp.atroseptica (Eca), were subjected to the same fertilization treatment. The incidence of blackleg and the level of seed tuber decay increased
from the uninoculated treatment to the higher inoculum level, but the degree varied considerably from one year to another.
Cv. Bintje was more susceptible to blackleg and yield loss caused by Eca than cv. Record. In 1990, when disease incidence
was high, the proportion of blackleg stems increased with increasing doses of nitrogen fertilizer which had been applied to
the seed crop, but was not significantly affected in 1988 and 1992. Seed tuber decay was retarded by the lowest nitrogen dose.
The yield of the subsequent crop was not affected by the nitrogen dose applied to the seed crop. 相似文献
10.
Comparison of hydroponic and aeroponic cultivation systems for the production of potato minitubers 总被引:1,自引:0,他引:1
Summary Two different cultivation systems, aeroponics and hydroponics in greenhouse beds, were compared for the production of potato
minitubers. Plants in the aeroponic system showed increased vegetative growth, delayed tuber formation and an extended vegetative
cycle of about seven months after transplanting. Therefore in 1999, two production cycles were obtained with the hydroponic
system, but only one with the aeroponic system. However, compared with total production in hydroponics, the tuber yield per
plant in the aeroponic system was almost 70% higher and tuber number more than 2.5 fold higher. Average tuber weight was reduced
by 33% in the aeroponic system. Advantages and possible problems with the aeroponic system for minituber production are discussed. 相似文献
11.
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
12.
M. K. Van Ittersum 《Potato Research》1992,35(3):261-269
Summary The variation in duration of dormancy within a seed tuber lot was studied over three years by harvesting individual plants
of cvs Diamant and Désirée from field plots and by storing the tubers at 18°C. The variation in dormancy within a tuber lot
was large (especially for cv. Diamant) and was mainly caused by variation within plants.
For cv. Diamant there was a close negative relation between dormancy and the cube root of tuber weight, whereas for cv. Désirée
a relation with tuber weight was almost absent.
The duration of dormancy of a seed lot comprising tubers with a narrow range in weight can be well described by two parameters.
It is proposed to maintain the moment of 80% sprouting as the criterion for the end of dormancy of a tuber lot and to characterize
the spread in dormancy duration by the time lapse between 10% and 90% sprouting. 相似文献
13.
D. C. E. Wurr Jane R. Fellows M. C. Hogge D. M. Booth E. J. Allen 《Potato Research》1992,35(2):149-155
Summary The number of stems per seed tuber produced by 17 seed stocks of cv. Record was determined in glasshouse and field experiments
to assess the feasibility of predicting the number of stems produced in the field. Multiple regression analysis showed that
seed tuber weight alone gave the most satisfactory fit to stems produced in the field, which was not improved by adding terms
involving the number of stems produced in the glasshouse.
Quadratic relationships between the number of above-ground stems per tuber and tuber weight were most appropriate for each
stock, with the fitted curves for individual stocks differing only in the constant term. However, there were significant rank
correlation coefficients between the constant terms for relationships between field stems and tuber weight and glasshouse
stems and tuber weight, suggesting that in other cultivars and seed stocks a predictive glasshouse test might still be useful. 相似文献
14.
Summary Factors affecting the volume expansion of potato cubes during puffing in a fluidised bed were examined. It was found that
puffing temperature, initial size, pre-drying time and puffing time influenced the degree of expansion of the cube during
the puffing step. Blanching alone was found not to influence expansion, but in conjunction with the other factors it was found
that blanched samples showed greater volume expansion than unblanched samples. The optimum conditions for maximum volume expansion
were found to be; blanching for 80 s, cube size between 7.5–12.5 mm, pre-drying time of 90 min. at 90°C and a puffing time
of 270s at 130°C. 相似文献
15.
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
16.
P. C. Struik A. J. Haverkort D. Vreugdenhil C. B. Bus R. Dankert 《Potato Research》1990,33(4):417-432
Summary Tuber-size distribution is regulated by many diverse, interacting mechanisms and is therefore difficult to understand and
manipulate. It is determined by plant density, number of stems per plant, number of tubers per stem, and yield. Seed size
and plant number per unit area are easy to control, but stem number is affected by less controllable factors. Interactions
between stems of different types are important for tuber-size distribution.
The hormonal regulation of stolonization and tuberization is still unknown, but under the conditions of north-west Europe
the process of tuber set (which is also poorly understood) makes a greater contribution to the final number of tubers than
tuberization. The total yield is also relevant, because it affects both the average tuber size and its variation.
Tubers on the same stem differ in timing, rate and duration of growth. The resulting hierarchy in sink strength is not consistent
over time. Several mechanisms are suggested for this hierarchy. 相似文献
17.
Summary Excessive fertilizer application in North Carolina, USA results in high residual soil levels of P, K and total soluble salts
in potato fields. Our objectives were to determine the salt sensitivity of three common cultivars (Atlantic. Snowden and Superior),
and the effects of planting density and fertilization on stand establishment, soilborne disease, and yield. Greenhouse results
suggest that potato growth and emergence, but not shoot initation, are reduced by high salinity. On a Portsmouth fine sandy
loam, high fertilizer rates did not reduce stands of cv. Atlantic in the field in 1996 or 1997. Excess N resulted in moreRhizoctonia stem canker in 1996, and lower yields at the lower planting density in 1997. Yield compensation for reduced plant density
occurred in 1997 at the lower N rates (56 and 112 kg N ha−1) and at the high PK rate (49 kg P and 139 kg K ha−1). 相似文献
18.
Summary In five field trials with the cultivars Gloria (early), Bintje (mid-early) Désirée (mid-late) and Morene (late), crops grown
from conventional 28–35 or 35–45 mm seed were compared with crops grown from microtubers, of various sizes and from various
sources, that had been producedin vitro. The following means to quicken initial crop development from the micropropagated material were tested: large microtubers,
plastic soil cover, and transplanting of plantlets grown from microtubers pre-planted in a glasshouse. Crops grown from microtubers
weighing less than half a gram yielded much less than crops grown from conventional seed crops but their yields were increased
by each treatment. With the later-maturing cultivars, which generally produce few tubers per plant, the yields within seed
grades from plants grown from transplanted microtuber plants were comparable with those of conventional crops. Reasons are
given, why direct planting of microtubers, with or without plastic foil, is not a practical option. 相似文献
19.
A device for measuring the growth of individual potato tubers non-destructively and precisely 总被引:1,自引:0,他引:1
P. C. Struik B. J. Schnieders L. H. J. Kerckhoffs G. W. J. Visscher 《Potato Research》1988,31(1):137-143
Summary A device for measuring the short-term fluctuations in volume of individual tubers is described. Its accuracy is mostly independent
of tuber growth stage, shape and malformations.
The coefficient of variation of volume of a tuber of 40 cm3 was usually well below 0.15% when the tuber was measured four times. 相似文献
20.
Stephen L. Love Timothy J. Herrman Asunta Thompsonjohns Timothy P. Baker 《Potato Research》1994,37(1):77-85
Summary Potato tuber glycoalkaloid content was measured in response to nitrogen fertilizer rate, storage temperature, length of storage
period and cultivar. Cvs Gemchip, Norchip and Russet Burbank were grown with applied nitrogen fertilizer rates of 0, 168 or
336 kg/ha and then stored at either 4.4 or 10°C. Total glycoalkaloid content was determined one month before harvest, at harvest,
after three months of storage and after nine months of storage. Higher rates of nitrogen, higher storage temperature and a
period of storage all resulted in significantly (P<0.05) higher concentration of glycoalkaloids. The cv Norchip had higher glycoalkaloids than cvs Gemchip or Russet Burbank.
Only the storage period had more influence than the environment (difference between years). Significant (P<0.05) two-way interactions were detected for year x cultivar, year x nitrogen, storage period x cultivar and nitrogen x cultivar.
Most interactions were due to the unique responses of cultivars. 相似文献