EFFECT OF FREEZING TEMPERATURE ON THE EFFICACY OF WILD OAT HERBICIDES

1988 ◽  
Vol 68 (3) ◽  
pp. 823-827 ◽  
Author(s):  
D. H. WILCOX ◽  
I. N. MORRISON ◽  
G. MARSHALL

In controlled environment experiments diclofop methyl, difenzoquat, flamprop methyl, fluazifop-P and seythoxydim were applied to wild oat at the three-leaf stage at recommended rates 10 h before or after a single night of freezing (−4 °C) temperature. Herbicide efficacy, as determined by the change in post-treatment dry weight accumulation of treated wild oats during the ensuing 3 wk period, was unaffected by the freezing temperature. The dry matter accumulation of wild oat exposed to the −4 °C temperature was reduced by 10–20% compared to plants which were grown under a constant 15/5 °C day/night regime.Key words: Oat (wild), frost, diclofop methyl, flamprop methyl, difenzoquat, fluazifop-P, sethoxydim

1988 ◽  
Vol 68 (4) ◽  
pp. 935-940 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. W. BRUULSEMA

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate


1978 ◽  
Vol 58 (1) ◽  
pp. 199-206 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. B. DAYNARD

Kernel development was studied in the maize (Zea mays L.) hybrids United-H106 and Funk’s G-4444, grown in a controlled-environment growth room. A method was employed in which husks were excised, and kernels were removed from the same set of ears at several subsequent sampling dates. This method did not affect the dry matter accumulation of the remaining kernels. Basal kernels (kernel numbers 6–15 in the row) and tip kernels (kernel numbers 31–40) were removed at 2-day intervals during the period from 10 to 20 days postsilking. Dry weight, ethanol-soluble sugar content, and starch content were determined for each sample. Accumulation of dry matter in the tip kernels ceased in a fraction of the United-H106 ears at the onset of the period of linear tip-kernel dry matter accumulation. Only small differences were observed in sugar content between growing and non-growing tip kernels of ears of United-H106. Starch appeared to continue to accumulate in kernels in which dry matter had ceased to accumulate. Except for a delay of approximately 2 days, the pattern of development of tip kernels in Funk’s G-4444 was similar to that of kernels at the base.


1983 ◽  
Vol 63 (2) ◽  
pp. 503-507 ◽  
Author(s):  
M. P. SHARMA ◽  
W. H. VANDEN BORN

Field experiments were conducted over a 2-yr period to evaluate the need for competition by crop plants along with the application of postemergence herbicides for wild oat (Avena fatua L.) control in barley and wheat. Barban, difenzoquat, and barban plus difenzoquat were used in barley and barban, benzoylprop ethyl, diclofop methyl, flamprop methyl, and barban plus benzoylprop ethyl were used in wheat, at the two-leaf stage and the four-leaf stage of wild oats seeded alone or in a crop. Barban and diclofop methyl were effective for wild oat control at both the two-leaf and four-leaf stage of wild oats. Benzoylprop ethyl, difenzoquat and flamprop methyl alone or in combination with barban were more effective at the four-leaf than at the two-leaf stage of wild oats. Herbicide treatments increased barley yield up to 84% and wheat yield up to 177%. In the absence of herbicide treatments, crop competition from barley or wheat reduced the wild oat dry weight by about 50%. Competition by crop plants was essential for effective wild oat control with all foliage-applied wild oat herbicides included in this study.Key words: Competition, crop, wild oat, herbicides, wheat, barley


1987 ◽  
Vol 67 (4) ◽  
pp. 1117-1120 ◽  
Author(s):  
D. H. WILCOX ◽  
I. N. MORRISON ◽  
G. MARSHALL

In controlled environment experiments, the efficacy of diclofop methyl applied to wild oat was reduced more than the efficacy of difenzoquat or flamprop methyl when the soil water content (SWC) was cycled between −0.24 and −2.18 MPa (low SWC) compared to when it was cycled between −0.03 and −0.06 MPa (high SWC). Similarly, at low SWC diclofop methyl was much less effective than either fluazifop-p-butyl or sethoxydim in reducing the post-treatment dry weight accumulation of the weed.Key words: Oat (wild), soil moisture, diclofop methyl, flamprop methyl, difenzoquat, fluazifop-p-butyl


1996 ◽  
Vol 121 (6) ◽  
pp. 1147-1151 ◽  
Author(s):  
Douglas C. Sanders ◽  
Jennifer D. Cure

The efficacy of undercutting as a technique to control bolting of two short-day onion cultivars was studied in controlled-environment chambers. `Buffalo' and `Granex 33' onions were grown to the third, fifth, and seventh visible leaf stages in a 10-hour photoperiod at 22/18 °C (day/night) and then exposed to 30, 40, 50, 60, or 70 days of vernalizing temperatures (10/10 °C). Half of the plants were undercut at the initiation of the vernalizing treatment. After vernalizing treatments, plants were returned to 14-hour photoperiods at 22/18 °C. `Buffalo', which is resistant to bolting, did not flower significantly under any of these conditions. The flowering response of `Granex 33' increased with leaf number at vernalization and as the duration of vernalization increased. Undercutting `Granex 33' increased the days of vernalization required for flowering and reduced the proportion of flowering relative to controls. Overall dry-matter accumulation was unaffected by leaf number at vernalization or the duration of vernalization but was reduced ≈30% by undercutting. In both cultivars, fresh mass per bulb decreased with increasing leaf stage of vernalization and number of vernalizing days. Undercutting also decreased fresh mass per bulb, but through its effect on bolting, undercutting increased marketable yield for plants vernalized and undercut at the fifth and seventh leaf stages.


Weed Science ◽  
1974 ◽  
Vol 22 (5) ◽  
pp. 476-480 ◽  
Author(s):  
Robert W. Neidermyer ◽  
John D. Nalewaja

The response of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.) to barban (4-chloro-2-butynyl-m-chlorocarbanilate) was studied as influenced by plant morphology and air temperature after application. Growth of wheat and wild oat seedlings was reduced by barban at 0.3 μg and 0.6 μg applied to the first node, respectively. Barban application to the base and midpoint of the first leaf blade required a lower dose to reduce wild oat growth than wheat growth. Increased tillering occurred from barban injury to the main culm in wheat. Wheat and wild oat susceptibility to barban increased as the post-treatment temperature decreased from 32 to 10 C. Barban selectivity for wild oats in wheat was greater at 27 and 21 C than at 16 and 10 C.


1991 ◽  
Vol 116 (6) ◽  
pp. 981-986 ◽  
Author(s):  
F.J.A. Niederholzer ◽  
R.M. Carlson ◽  
K. Uriu ◽  
N.H. Willits ◽  
J.P. Pearson

A study was undertaken to determine the seasonal dynamics of leaf and fruit K content and the influence of tree K status and fruit growth on leaf and fruit K accumulation rates in French prune (Prunus domestics L. cv. d'Agen). Mature trees in a commercial orchard were treated with various rates of K2 SO4. (O to ≈20 kg/tree) in the fall. Fruit dry weight yield per tree at harvest and fruit K content were higher for high-K trees, but fruit percent K (by dry weight) was ≈1.0% for all trees. Leaf scorch and subsequent abscission severely reduced the canopy of K-deficient trees. Significant positive linear relationships between leaf and fruit K accumulation rates existed for the periods of 28 Apr.-28 May (May) and 28 May-7 July (June). A significant negative linear relationship existed between these two criteria from 7 July-3 Aug. (July). May (0.237 mg K per fruit-day) and July (0.267 mg K per fruit-day) mean fruit K accumulation rates were similar, but both were significantly higher (P = 0.001) than those for June (0.140 mg K per fruit-day). Mean leaf K accumulation rates for May (- 0.007 mg K per leaf-day) and July (-0.010 mg K per leaf-day) were similar, but both were significantly (P = 0.001) less than for June (0.005 mg K per leaf-day). Potassium per fruit accumulation was highest in trees with highest K status. Periods of net leaf K efflux and influx did not precisely correlate with fruit growth stages measured by fruit dry weight. The period of lowest fruit K accumulation (28 May-7 July) coincided with the period of maximum dry matter accumulation by the kernel. After 7 July, all increases in fruit dry weight and K content were due to mesocarp growth.


1966 ◽  
Vol 46 (2) ◽  
pp. 195-203 ◽  
Author(s):  
B. Stanfield ◽  
D. P. Ormrod ◽  
H. F. Fletcher

Effects of day/night temperature regimes from 7/4 to 32/24 °C on growth and development of Pisum sativum L. var. Dark Skin Perfection were studied in controlled-environment cabinets. Light intensity was about 1500 foot-candles and the photoperiod was 16 hours. Rate of plant development, in terms of nodes produced per day, increased steadily as the average temperature increased. Rate of stem elongation, however, was most rapid at 21/13 °C; and plant height was greatest at 16/10 °C. On a dry matter accumulation rate basis, vine growth decreased above and below a temperature optimum which shifted from 21/16 to 16/10 °C in the course of plant development. The combination of high day and high night temperatures caused an increase in the number of nodes to the first flower. Tillering was most prolific at the lower temperatures and was absent at 32 °C day temperatures. Pea yield decreased as temperature increased above 16/10 °C, due mainly to a reduction in the number of pods per plant.


1969 ◽  
Vol 20 (3) ◽  
pp. 417 ◽  
Author(s):  
JH Silsbury

Lolium rigidum Gaud. and a summer-dormant and a non-dormant form of Lolium perenne L. were grown as seedling plants for 32 days in controlled environment cabinets at constant temperatures of either 10, 20, or 30°C and in all cases with a 16-hr photoperiod at a light intensity of 3600 lm ft-2. Sampling at 4-day intervals permitted the detailed examination of dry matter growth curves. Differences in total dry matter production were related to initial differences in seedling dry weight, and the general responses to temperature were similar for each ryegrass. Total dry matter production was greatest at 20°C and lowest at 10°. A temperature of 30° did not induce dormancy in the summer-dormant ryegrass but did depress growth. Relative growth rate fell with time at each temperature.


1989 ◽  
Vol 25 (3) ◽  
pp. 349-355 ◽  
Author(s):  
S. S. Parihar ◽  
R. S. Tripathi

SUMMARYThe response of chickpea to irrigation and phosphorus was studied at Kharagpur in Eastern India. Irrigation scheduling was based on the ratio between irrigation water applied and cumulative pan evaporation (ID/CPE), and had little effect on dry matter accumulation. Increasing the frequency and amount of irrigation reduced the number and dry weight of nodules per plant, which increased to a maximum 70 days after sowing and then declined. Irrigation significantly reduced grain yield as a result of excessive vegetative growth at the expense of pod formation. Application of phosphorus promoted nodulation and increased both nodule dry weight and the concentration of N, P and K in grain and stover. Uptake of N, P and K by the crop was also increased.


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