scholarly journals Assessment of metribuzin effects on potatoes using a method of very rapid fluorescence induction

2011 ◽  
Vol 48 (No. 3) ◽  
pp. 107-117
Author(s):  
J. Dvořák ◽  
I. Remešová

Effects of increasing doses of the herbicidal preparation Sencor 70 WP (metribuzin a.i.) on selected potato varieties were studied in a&nbsp;field and pot experiments using very rapid fluorescence induction (vrFI). Tuber yield, and in pot experiments a&nbsp;tuber number and characteristics of the aboveground biomass were assessed. The curve of rapid induction goes through the O-J-I-P phases. The parameters Fo, Fv/Fp and rFj were measured. Based on changes in the vrFI parameters in comparison with controls, varieties were ranked according to sensitivity to metribuzin in field experiments. Keřkovsk&eacute; rohl&iacute;čky and Ukama were the most sensitive varieties and Impala the least sensitive variety. In pot experiments in the growth chamber, significant decrease in tuber weight vs controls was found in sensitive varieties Keřkovsk&eacute; rohl&iacute;čky (in 1998, 0.75 kg.ha<sup>&ndash;1</sup> Sencor 70 WP decreased tuber weight by 28% and 1.5 kg.ha<sup>&ndash;1</sup> by 89%) and Ukama (in 1997, at 1.5 kg.ha<sup>&ndash;1</sup> by 35%). Under stable conditions in the growth chamber, there were lower differences in the rFj parameter in these varieties in comparison with controls than in resistant ones. Based on this finding it can be assumed that the sensitivity of varieties can be determined according to rFj changes under stable ambient conditions.

1979 ◽  
Vol 59 (4) ◽  
pp. 423-429 ◽  
Author(s):  
R. B. McKERCHER ◽  
W. R. McGREGOR

Applications of Ca to soil in both growth chamber and field experiments increased triallate [S-(2,3,3-trichloroallyl)-diisopropylthiocarbamate] activity. Ca appears to affect the distribution of triallate between the colloid and soil solution causing a shift of triallate toward the solution phase. These effects are measurable in pot experiments at Ca additions of about 1 meq/100 g soil or at field applications of 2.5 tonnes per hectare (1 ton per acre) of Ca(OH)2.


2014 ◽  
Vol 60 (No. 8) ◽  
pp. 379-386 ◽  
Author(s):  
M. Kołodziejczyk

The effect of nitrogen fertilization and microbial preparations on yielding and development of potato tuber yield components were assessed in field experiments conducted under soil conditions of Luvic Chernozem. The factors of the experiment were nitrogen fertilization levels: 0, 60, 120 and 180 kg N/ha and the following preparations: BactoFil B10, effective microorganisms and UG<sub>max</sub> soil fertilizer. Nitrogen fertilization caused a significant increase in marketable yield of potato tubers. Yield increments on individual fertilizer treatments ranged from 66% to 140%. An evident effect of this factor was also visible regarding the yield components values. Increase in the number of main stems per 1 m<sup>2</sup> under the influence of growing nitrogen doses occurred from the fertilization level 120 kg N/ha, whereas the number of tubers per 1 stem increased only to the level of 60 kg N/ha. Each nitrogen dose applied within the range to 180 kg N/ha caused a marked increase in an average tuber weight. Conducted investigations demonstrated an unfavourable effect of microbial preparations on the marketable crop yield of tubers and formation of yield components. On the objects where microbial preparations were applied, the marketable yield was lower by 1.5 to 2.3 t/ha than in the control. Analysis of linear regression revealed occurrence of significant dependencies between the total tuber yield and the values of individual yield components. The relationships were the most visible for an average tuber weight formation as evidenced by the value of coefficient of determination&nbsp;(R<sup>2</sup> = 0.983).


2012 ◽  
Vol 151 (3) ◽  
pp. 368-380 ◽  
Author(s):  
MULUGETA TAYE ◽  
W. J. M. LOMMEN ◽  
P. C. STRUIK

SUMMARYPlectranthus edulis is an ancient tuber crop, cultivated in Ethiopia, which produces stem tubers on stolons below the ground; however, agronomic and physiological information on this crop is scarce. Three field experiments were carried out at each of two locations (Awassa and Wondogenet, Ethiopia). Expt 1 dealt with the effects of breaking a seed tuber into different numbers of seed pieces before planting, Expt 2 assessed the effect of the weight of the seed tuber piece and Expt 3 investigated the effect of planting different numbers of seed pieces per planting hole. Cultivar Lofuwa was planted in Awassa, whereas cvar Chankua was planted in Wondogenet. Breaking seed tubers in Expt 1 resulted in more main stems/hill, more tubers and smaller individual tubers. In Wondogenet, the tuber yield also increased. Breaking did not affect the number of stolons/m2. Expt 2 indicated that when only one seed piece was planted per planting hole, smaller seed pieces gave fewer stems, fewer stolons and fewer tubers/m2, smaller tubers and lower tuber yields. Expt 3 showed that planting more seed pieces/planting hole gave more stems, more stolons and more tubers/m2, thus increasing tuber fresh yield/m2, whereas the mean tuber weight was not consistently affected. Across all experiments, the tuber yield increased when the number of main stems increased up to three main stems/m2. Higher tuber yields resulting from experimental treatments were either achieved by an effect on number of tubers alone or by combined effects on number of tubers and mean tuber weight, but not by an effect on mean tuber weight alone. The number of small tubers was high in all experiments. Breaking a seed tuber into two or three pieces before planting them in one planting hole consistently resulted in increased numbers of main stems and tuber yield.


1988 ◽  
Vol 28 (6) ◽  
pp. 765 ◽  
Author(s):  
MDA Bolland ◽  
MJ Baker

Seed of 2 cultivars of wheat (Triticum aestivum) and 1 burr medic (Medicago polymorpha) with increasing phosphorus (P) concentrations (wheat 1.4-3.7 g P/kg dry matter, medic 3.3-7.9 g P/kg dry matter) were collected from field experiments with variable levels of applied superphosphate (wheat 0- 577 kg P/ha, medic 0-364 kg P/ha) in south-western Australia. These seeds were used in further experiments to examine the effect of seed P concentration on the subsequent dry matter (DM) production of seedlings and plants in 3 glasshouse pot experiments and 1 field experiment. Seed of the same size (wheat, 35 mg/seed; medic, 3.6 mg/seed) but with increasing P concentration produced substantially higher DM yields in the absence or presence of freshly applied superphosphate P up to 28-35 days after sowing in the pot experiments and 67 days after sowing in the field experiment.


1983 ◽  
Vol 63 (2) ◽  
pp. 199-210 ◽  
Author(s):  
C. W. BULLEN ◽  
R. J. SOPER ◽  
L. D. BAILEY

Growth chamber and field experiments were conducted on Southern Manitoba soils, low in available soil phosphorus, to investigate the effects of various placement methods and levels of phosphorus fertilizer on soybean (Glycine max (L.) Merrill ’Maple Presto’). It was found that soybean responded well to applied phosphorus on low-P soil in growth chamber studies. In the first growth chamber experiment, P was applied in solution to 100%, 50%, 25%, 12.5% and 1% of the total soil volume. Dry matter yields, total phosphorus uptake and utilization of fertilizer P increased at each level of applied P as the size of the phosphated band was decreased. The results were partly attributed to greater chemical availability of P in the smaller zones of P fertilizer reaction. In a second growth chamber experiment, soybeans responded differently to phosphorus banded in six different locations. Placement of the fertilizer 2.5 cm directly below the seed was more effective in increasing dry matter yield, total phosphorus uptake and fertilizer P utilization than placement 2.5 cm and 5 cm away at the same depth or placement 5 cm below the seed, whether the band was directly below, 2.5 cm away or 5 cm away. Soybean yield responses in the field were greatest with P banded 2.5 cm directly below the seed on low-P soils. Placement of P 2.5 cm below the seed resulted in grain yields that were 64% and 50% higher (at the two sites) than those obtained in control plots. Sidebanding P, 2.5 cm below and 2.5 cm away from the seed at the same level of application, improved grain yields of control plots by 40% and 39%. Seed placement and broadcast applications of P were not as effective in increasing grain yields. Broadcasting P in fall or in spring at rates of up to 52.38 kg P/ha did not result in significantly higher grain yields than those obtained in control plots. Placement of P in contact with the seed appeared to reduce seedling emergence, resulting in depressed yields when 52.38 kg P/ha were applied. Key words: Glycine max L. Merrill, ’Maple Presto’


2010 ◽  
Vol 32 (4) ◽  
pp. 419 ◽  
Author(s):  
Xing Teng ◽  
Lei Ba ◽  
Deli Wang ◽  
Ling Wang ◽  
Jushan Liu

Many studies indicated that saliva from herbivores might be involved in plant growth responses when plants have been grazed. However, there is currently no general agreement on whether saliva can affect plant growth. Our aims were to determine the growth response of plants to sheep saliva after defoliation under diverse environmental conditions (different sward structures), and whether the effect of saliva is influenced by time (duration) after its application. We conducted field experiments with clipping treatments and the application of sheep saliva to the damaged parts of tillers to simulate sheep grazing on the perennial grass Leymus chinensis (Trin.) Tzvelev during the early growing seasons. Results demonstrated that clipping with saliva application significantly increased tiller numbers 8 weeks after treatments in comparison with clipping alone. A key finding is that the effect of sheep saliva on plant growth was short-lived. Clipping with saliva application increased leaf weight in the second week, while clipping alone had no effect. Moreover, clipping with saliva application promoted the elongation of new leaves (not the old ones) in the first week whereas clipping alone was ineffective. Results also showed that there were no differences between clipping with saliva application and clipping alone for relative height growth rate and aboveground biomass. Therefore, we concluded that saliva application to clipping treatment would produce an additional effect compared to clipping alone for the plant and the positive effects are time dependent. The additional effects primarily embodied in the individual level of plant, such as the changes of leaf weight and leaf length. Beyond the level, the effects of saliva only produced many more tiller numbers rather than the accumulation of aboveground biomass.


Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 469-474 ◽  
Author(s):  
A. Gamliel ◽  
A. Grinstein ◽  
Y. Peretz ◽  
L. Klein ◽  
A. Nachmias ◽  
...  

The use of gas-impermeable films to reduce the dosage of methyl bromide (MB) required to control Verticillium wilt in potatoes was examined in field experiments, conducted in soils naturally infested with Verticillium dahliae. The incidence and severity of Verticillium wilt were significantly reduced (by 74 to 94%) by fumigation with MB at 50 g/m2 under standard low density polyethylene (LDPE) or at 25 g/m2 under gas-impermeable films. Fumigation at 25 g/m2 under LDPE was less effective. Disease severity was inversely correlated (r2 = 0.89 to 0.91) with chlorophyll content in the leaves. Fumigation also reduced (by 89 to 100%) stem colonization by the pathogen. Potato yield in the fumigated plots was significantly higher (26 to 69%), than in their nonfumigated counterparts, and was inversely correlated with disease index (r2 = 0.69 to 0.9). The percentage of high-value tubers (above 45 g) was 52 to 56% of total yield in the fumigated plots as compared with 32 to 40% in the nonfumigated controls. Thus, fumigation also improved the commercial quality of tuber yield. Effective control of V. dahliae and yield increases following MB fumigation at the recommended dosage or at a reduced dosage with gas-impermeable films was also observed in a consecutive crop. These results were verified in a large-scale field experiment using commercial applications, further demonstrating the feasibility of reducing MB dosages under farm conditions, without reducing its effectiveness in terms of disease control and yield improvement.


2013 ◽  
Vol 36 (10) ◽  
pp. 1871-1887 ◽  
Author(s):  
ALEXANDER STRIGENS ◽  
NICLAS M. FREITAG ◽  
XAVIER GILBERT ◽  
CHRISTOPH GRIEDER ◽  
CHRISTIAN RIEDELSHEIMER ◽  
...  

Theoretical indications of the magnitude of horizontal spread resulting from the interaction between vertical diffusion and the wind profile are briefly reviewed. Assuming a fairly realistic form for the spectrum of turbulence the effect of this interaction is evaluated from a treatment by F. B. Smith, and this is combined with the theoretical growth arising directly from the horizontal component of turbulence to give a total crosswind growth curve. Two series of field experiments on dispersion in stable conditions are examined, one in Sweden using an elevated source of smoke puffs, the other in the U.S.A. using a continuous ground release of a fluorescent tracer. Both indicate that distortion of the plume by the turning of the wind became significant beyond 2-3 km downwind, but that the immediate transference of the effect to enhance the spread at a given level was not important within about 5 km for the elevated source or about 12 km for the ground source.


2020 ◽  
Vol 3 (2) ◽  
pp. 193-204
Author(s):  
Kalyani Shrestha ◽  
Shrawan Kumar Sah ◽  
Reeti Singh ◽  
Yam Narayan Devkota

The suitability of crop varieties in a particular location determines the productivity of crops. A field experiment was conducted from February to May 2020 at Shankharapur, Kathmandu, Nepal to evaluate the growth and productivity of potato varieties with and without mulch. Five potato varieties (Cardinal, Janakdev, Khumal Bikas, MS- 42.3, Panauti Local) were evaluated under straw-mulch and no-mulch conditions. The treatments were arranged in two factorial Randomized Complete Block Design (RCBD) with 3 replications. The results revealed that the highest tuber yield was produced by Janakdev (34.29 t ha-1) followed by Panauti Local (29.52 t ha-1). Similarly, straw-mulch gave higher yield (25.9 t ha-1) as compared with no mulch condition (21.73 t ha-1). The higher tuber yield in the Janakdev and Panauti Local was because of higher tuber weight per hill, higher number and weight of medium size (50 -100 g) and oversize (> 100 g) tuber per hill. Similarly, higher yield in straw mulch was due to higher number and weight of tuber per hill. Higher gross return, net return was observed and the benefit cost ratioin varieties Janakdev (4.08) and Panauti Local (3.53) and rice straw mulch (2.88). Therefore, potato varieties Janakdev and Panauti Local with straw mulch are most suitable for Kathmandu like climate for improving productivity and profitability.


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