EFFECT OF PHENOXY HERBICIDES ON COLD HARDINESS OF WINTER WHEAT

1979 ◽  
Vol 59 (1) ◽  
pp. 237-240 ◽  
Author(s):  
S. FREYMAN ◽  
W. M. HAMMAN
Keyword(s):  
Winter Wheat ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Controlled Environment ◽  
Minor Effect ◽  
Active Growth ◽  
Phenoxy Herbicides ◽  
Freezing Test ◽  
Environment Experiment ◽  
A Minor

In a controlled environment experiment, five phenoxy herbicides were sprayed at two rates on 14-day-old winter wheat (Triticum aestivum L. emend Thell ’Norstar’). After 7 additional days of active growth, the plants were cold-hardened for 14 days and then subjected to a freezing test. Four of the herbicides — MCPA amine, 2,4-D ester, 2,4-DB, 2,4-D amine — significantly reduced the cold hardiness of winter wheat whereas diclofop methyl had a minor effect. The reduction in hardiness was greater at the higher rates of application than at the lower rates.

Effect of soil temperature, seeding depth and cultivar on wheat tolerance to simulated ethalfluralin carryover

1997 ◽  
Vol 77 (1) ◽  
pp. 181-188
Author(s):  
A. L. Darwent ◽  
L. P. Lefkovitch ◽  
P. F. Mills
Keyword(s):  
Soil Temperature ◽  
Plant Density ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Controlled Environment ◽  
Minor Effect ◽  
Cultivar Selection ◽  
Soil Temperatures ◽  
Environment Experiment ◽  
A Minor

Field and controlled environment experiments were conducted at Beaverlodge, Alberta to determine the effect of soil temperature, seeding depth and cultivar on wheat (Triticum aestivum L.) tolerance to ethalfluralin. In one experiment, ethalfluralin was applied and incorporated, and wheat was seeded at several depths in late April/early May when soil temperatures were lowest or in late May when soil temperatures had increased. Mean 3-yr wheat yields decreased by 45% as the rate of ethalfluralin increased from 0 to 0.75 kg ha−1 and by 21% as the depth of seeding increased from 4 to 12.5 cm but the effect of ethalfluralin on yields was similar regardless of the soil temperature (time of seeding). Mean plant density decreased by 55% as the rate of ethalfluralin increased and by 25% as the depth of seeding increased. Reductions in mean plant density from ethalfluralin were slightly greater when seeded into the warmer soils. In another experiment, the effect of ethalfluralin on the yields of three wheat cultivars, Laura, Conway and Biggar was similar, i.e. the cultivar × rate of ethalfluralin interaction was not significant. However, the mean plant density of Biggar, averaged over rates of ethalfluralin, was less than that of the other cultivars in 1 of 2 yr. In a controlled environment experiment, the oven-dry weight and percent emergence of wheat shoots of the cultivars, Katepwa, Laura and Conway, seeded at 1.5 or 4 cm into soils containing ethalfluralin at concentrations of 0 to 4 ppm and maintained at temperatures of 4.5 or 15 °C, were reduced by decreases in temperature and increases in the rate of herbicide and depth of seeding. However, the interaction of soil temperature × rate of ethalfluralin was not significant for the oven-dry weight of the wheat shoots and the reduction in percent emergence of the wheat shoots as the rate of ethalfluralin increased was only slightly greater at 4.5 °C than at 15 °C. These results indicate that soil temperature and cultivar selection have a minor effect on wheat tolerance to ethalfluralin while herbicide concentration and depth of seeding have a major impact. Key words: Ethalfluralin, wheat, seeding depth, soil temperature, cultivar

INFLUENCE OF DURATION OF GROWTH, SEED SIZE, AND SEEDING DEPTH ON COLD HARDINESS OF TWO HARDY WINTER WHEAT CULTIVARS

1978 ◽  
Vol 58 (4) ◽  
pp. 917-921 ◽  
Author(s):  
S. FREYMAN
Keyword(s):  
Winter Wheat ◽  
Cold Hardiness ◽  
Marked Effect ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Controlled Environment ◽  
Small Seed ◽  
Winter Wheat Cultivars ◽  
Freezing Test ◽  
Test Plants

Two winter wheat (Triticum aestivum L.) cultivars, Kharkov 22 MC and Winalta, were grown for 14 or 28 days under controlled environment from large or small seed or from seed with about half the endosperm removed. The kernels were seeded either 1 or 5 cm deep. After a 14-day cold hardening period followed by a freezing test, plants that had grown actively for 28 days were hardier than those that had grown actively for only 14 days. Plants from large kernels were hardier than those from small kernels, which in turn were slightly hardier than those from kernels with half the endosperm removed. Deep seeding reduced cold hardiness. The treatments had a marked effect on the dry weight of crowns and a smaller effect on crown total available carbohydrate content, both of which were positively correlated with cold hardiness, whereas water content was negatively correlated with cold hardiness.

RELATIONSHIP OF SOIL FERTILITY TO COLD HARDINESS OF WINTER WHEAT CROWNS

1979 ◽  
Vol 59 (3) ◽  
pp. 853-855 ◽  
Author(s):  
S. FREYMAN ◽  
M. S. KALDY
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Soil Fertility ◽  
Water Content ◽  
Cold Hardiness ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Controlled Environment ◽  
Prairie Soil ◽  
Relationship Of

In two controlled-environment experiments, N fertilizer applied to a Dark Brown prairie soil decreased cold hardiness of winter wheat (Triticum aestivum L.), while P applied in the absence of N had little effect. When applied together, P counteracted the effect of N and produced plants as hardy as those that had received no fertilizer. The soil was rich in K; consequently application of additional amounts of this element had no effect on cold hardiness. The correlation coefficient between dry weight of crowns and cold hardiness (LT50) was not sigificant, but that between water content and LT50 was highly significant.

COLD HARDENING AND DEHARDENING RESPONSES IN WINTER WHEAT AND WINTER BARLEY

1975 ◽  
Vol 55 (2) ◽  
pp. 529-535 ◽  
Author(s):  
M. K. POMEROY ◽  
C. J. ANDREWS ◽  
G. FEDAK
Keyword(s):  
Winter Wheat ◽  
Cold Hardiness ◽  
Maximum Level ◽  
Freezing Temperature ◽  
Triticum Aestivum L ◽  
Winter Barley ◽  
Lethal Temperature ◽  
Hordeum Vulgare L ◽  
Wheat Seedlings ◽  
Time Required

Increasing the duration of freezing of Kharkov winter wheat (Triticum aestivum L.) demonstrated that severe injury does not occur to plants at a freezing temperature (−6 C) well above the lethal temperature for at least 5 days, but progressively more damage occurs as the temperature approaches the killing point (−20 C). High levels of cold hardiness can be induced rapidly in Kharkov winter wheat if seedlings are grown for 4–6 days at 15 C day/10 C night, prior to being exposed to hardening conditions including diurnal freezing to −2 C. The cold hardiness of Kharkov and Rideau winter wheat seedlings grown from 1-yr-old seed was greater than that from 5-yr-old seed. Cold-acclimated Kharkov winter wheat and Dover winter barley (Hordeum vulgare L.) demonstrated the capacity to reharden after varying periods under dehardening conditions. The time required to reharden and the maximum level of hardiness attained by the plants was dependent on the amount of dehardening. Considerable rehardening was observed even when both dehardening and rehardening were carried out in the dark.

DEHARDENING OF WINTER WHEAT AND RYE UNDER SPRING FIELD CONDITIONS

1977 ◽  
Vol 57 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
D. B. FOWLER ◽  
L. V. GUSTA
Keyword(s):  
Moisture Content ◽  
Winter Wheat ◽  
Cold Hardiness ◽  
Dry Weight ◽  
Test Site ◽  
Triticum Aestivum L ◽  
Winter Rye ◽  
Fresh Weight ◽  
Seeding Date ◽  
Secale Cereale L

Changes in cold hardiness (LT50), fresh weight, dry weight and moisture content were measured on crowns of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) taken from the field at weekly intervals in the spring of 1973 and 1974 at Saskatoon, Sask. In all trials, Frontier rye came out of the winter with superior cold hardiness and maintained a higher level of hardiness during most of the dehardening period. For cultivars of both species, rapid dehardening did not occur until the ground temperature at crown depth remained above 5 C for several days. Changes in crown moisture content tended to increase during dehardening. Over this same period crown dry weight increased for winter rye but did not show a consistent pattern of change for winter wheat. Two test sites were utilized in 1974. One site was protected by trees and the other was exposed. General patterns of dehardening were similar for these two sites, but cultivar winter field survival potentials were reflected only by LT50 ratings for the exposed test site. The influence of fall seeding date on spring dehardening was also investigated. Late-seeded wheat plots did not survive the winter in all trials. However, where there was winter survival, no differences in rate of dehardening due to seeding date were observed.

EFFECT OF A Rht GENE CONDITIONING THE SEMIDWARF CHARACTER ON WINTERHARDINESS IN WINTER WHEAT (Triticum aestivum L. em Thell)

1988 ◽  
Vol 68 (2) ◽  
pp. 301-309 ◽  
Author(s):  
D. J. GILLILAND ◽  
D. B. FOWLER
Keyword(s):  
Triticum Aestivum ◽  
Gibberellic Acid ◽  
Winter Wheat ◽  
Great Plains ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Breeding Strategy ◽  
Sensitivity Analyses ◽  
Wheat Cultivars ◽  
Winter Wheat Cultivars

In the northern part of the North American Great Plains, the level of cultivar winter-hardiness required for winter wheat (Triticum aestivum L.) production is extremely high. Presently, available winter wheat cultivars with adequate winterhardiness are tall and, under favourable growing conditions, crop lodging and excessive amounts of straw can present serious production problems. Consequently, cultivars with short, stiff straw and a high harvest index would be desirable for high production areas within this region. However, semidwarf cultivars with superior winterhardiness have not yet been developed. In this study, six GA-insensitive (Rht) semidwarf parents with poor to moderate winterhardiness were crossed with three GA-sensitive (rht) tall parents possessing good winterhardiness to produce 20 different single, three-way and double crosses. These crosses were evaluated to determine if the GA-insensitive character could be combined with a high level of winterhardiness in winter wheat. Gibberellic acid (GA) sensitivity analyses of F2 seedlings established that a single GA-insensitive gene was involved in each cross. F2-derived F3 and F3-derived F4 lines were assessed for GA-sensitivity and winterhardiness levels were determined from field survival at several locations in Saskatchewan, Canada. Winter survival of homozygous GA-sensitive and GA-insensitive lines were similar in both generations. Lines with winterhardiness levels similar to those of the three tall parent cultivars were recovered in all GA-response classes. The absence of a meaningful pleiotropic effect of Rht genes on winterhardiness indicates that the reason semidwarf cultivars with superior winterhardiness levels have not been developed is due to the lack of a concentrated breeding effort to combine the two characters. A breeding strategy for the production of adapted winterhardy semidwarf winter wheat cultivars is discussed. The influence of endogenous gibberellin levels on cold hardiness in winter wheat is also considered.Key words: Cold hardiness, field survival, Triticum aestivum L, semidwarf, Gibberellic acid

Prediction of cold hardiness in Douglas fir seedlings by index of injury and conductivity methods

1976 ◽  
Vol 6 (4) ◽  
pp. 511-515 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Cold Hardiness ◽  
Douglas Fir ◽  
Critical Values ◽  
Promising Method ◽  
Controlled Environment ◽  
Electrical Conductivities ◽  
Freezing Temperatures ◽  
Environment Experiment ◽  
Whole Plants ◽  
Stem Segments

Electrical conductivities of diffusate from stem segments of Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) were measured after exposing segments to various freezing temperatures and after heat killing. These data were expressed as conductivity percentage (conductivity after freezing as a percentage of conductivity after heat killing) or as index of injury (It, equivalent to conductivity percentage corrected for conductivity of unfrozen sample). Conductivity percentage, meaned over six test temperatures, predicted the temperature lethal to subsamples of whole plants exposed to different freezing temperatures reasonably well (R2 = 0.77, SEE = ±3.3 °C). However, 'critical' values of It associated with the temperature lethal to 50% of whole plants (T50) could only be determined for the three lowest test temperatures, and they varied from 32 to 40. In a controlled-environment experiment, levels of hardiness predicted by mean conductivity percentage, which seemed the most promising method, did not fully agree with survival results obtained from whole plants after freezing tests.

AN EVALUATION OF SEVERAL CHEMICAL TESTS AS POSSIBLE SELECTION MEASURES FOR WINTERHARDINESS IN WHEAT

1983 ◽  
Vol 63 (1) ◽  
pp. 115-119 ◽  
Author(s):  
L. V. GUSTA ◽  
D. B. FOWLER ◽  
N. J. TYLER
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Key Words ◽  
Uronic Acid ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Survival Prediction ◽  
Selection Measures ◽  
Highly Correlated ◽  
Chemical Characters

Ten chemical characters and crown LT50s were measured on 14 cold-hardened cultivars of winter wheat (Triticum aestivum L. em. Thell.) to determine their usefulness in winter survival prediction tests. Differences among genotypes with a range of cold hardiness potential (LT50 −13 °C to −20 °C) were significant for 6 to 10 characters evaluated. Crown LT50 was the best prediction of field survival (FSI). Cell sap viscosity, total crown nitrogen, crown ethanol, insoluble nitrogen, and crown uronic acid were highly correlated with both FSI and LT50. Proline, pH and ATP were not significantly correlated with either FSI or LT50.Key words: Chemical tests, selection, winterhardiness, wheat

FALL GROWTH AND COLD ACCLIMATION OF WINTER WHEAT AND RYE ON SALINE SOILS

1981 ◽  
Vol 61 (2) ◽  
pp. 225-230 ◽  
Author(s):  
D. B. FOWLER
Keyword(s):  
Salt Stress ◽  
Winter Wheat ◽  
Cold Acclimation ◽  
Soil Salinity ◽  
Cold Hardiness ◽  
Calcium Content ◽  
Triticum Aestivum L ◽  
Saline Soils ◽  
Variable Effect ◽  
Sodium Magnesium

The effect of salt stress during the period of cold acclimation for winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) was studied in field trials on saline soils north of the Quill Lakes in the northeastern corner of the agricultural area of Saskatchewan. Shoot and crown dry weights and crown moisture, sodium, magnesium and sulfur contents were all strongly influenced by variables related to soil conductivity. Increased levels of soil sodium and magnesium salts were reflected by increased concentrations of sodium, magnesium and sulfur in the crown tissue. In contrast, crown calcium content decreased significantly with increased soil salinity. Soil salinity had a variable effect on cold hardiness. Although the general trend was towards reduced cold tolerance of plants with increased salt stress, reductions were not large enough to be of practical concern.

A COMPARISON OF COLD HARDINESS AND ICE ENCASEMENT TOLERANCE OF TIMOTHY GRASS AND WINTER WHEAT

1983 ◽  
Vol 63 (2) ◽  
pp. 429-435 ◽  
Author(s):  
C. J. ANDREWS ◽  
B. E. GUDLEIFSSON
Keyword(s):  
Low Temperature ◽  
Winter Wheat ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Similar Rate ◽  
Phleum Pratense ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Timothy Grass ◽  
Ice Encasement

In the falls of 1979 and 1980 Salvo timothy grass (Phleum pratense L.) showed cold hardiness similar to Norstar winter wheat (Triticum aestivum L.) but significantly greater hardiness than Fredrick winter wheat. Ice tolerance of Salvo, with LI50 values of 29 and 45 days in the 2 yr, was more than twice that of the wheats. In controlled environments, seedlings of three timothy cultivars showed relatively low cold hardiness, but about threefold greater ice tolerance than the wheats. An Icelandic timothy cultivar, Korpa, showed greater ice tolerance than the Norwegian Engmo, and the Canadian cultivar Salvo. Fredrick wheat, and Korpa timothy cold hardened at a similar rate for 4 wk, but Korpa continued to harden to − 18 °C up to 6 wk of low temperature growth. Korpa rapidly attained a high tolerance to ice encasement in 2 wk of low temperature growth while Fredrick attained relatively low ice tolerance reaching a maximum at 3 wk of growth. There is little association between cold and ice tolerance in timothy, and there is a major difference in the ice tolerances of timothy and winter wheat. This high ice tolerance is likely to be a major cause of the superior survival of timothy in conditions of high winter stress. Key. words: Triticum, Phleum, acclimation, resistance, low temperature, frost

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