CHANGES IN COLD HARDINESS, ICE TOLERANCE AND TOTAL CARBOHYDRATES OF WINTER WHEAT UNDER VARIOUS CUTTING REGIMES

1984 ◽  
Vol 64 (3) ◽  
pp. 547-558 ◽  
Author(s):  
C. J. ANDREWS ◽  
M. K. POMEROY ◽  
W. L. SEAMAN

Fredrick winter wheat was subjected to a number of cutting (defoliation) regimes in controlled environments and in the field in 2 yr to investigate the effects of simulated forage removal on winter survival parameters. In controlled environments, cutting at 4 wk and 8 wk reduced cold hardiness and ice tolerance markedly in plants grown for 5 days, and 14 days at warm temperatures before hardening. Total nonstructural carbohydrates (TNSC) in plant crowns were reduced by all regimes. In the field, the effects of single cuttings were not as large, but generally there were slight reductions in cold hardiness, ice tolerance, and crown TNSC. A slight increase in cold hardiness was associated with multiple cutting in both years but this was not normally reflected in an increase in winter survival. A reduction in ice tolerance by cutting of plants in a plot with low soil moisture was not seen on a periodically flooded plot. Cutting reduced fresh weight of plants and root number, and markedly increased crown moisture content. Overall, despite a variable effect on a number of winter survival parameters, cutting of Fredrick winter wheat appeared to be hazardous to its overwintering potential.Key words: Triticum, acclimation, encasement, clipping, grazing, defoliation

1977 ◽  
Vol 57 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
D. B. FOWLER ◽  
L. V. GUSTA

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.


1976 ◽  
Vol 56 (1) ◽  
pp. 45-50 ◽  
Author(s):  
D. B. FOWLER ◽  
L. V. GUSTA ◽  
K. E. BOWREN ◽  
W. L. CROWLE ◽  
E. D. MALLOUGH ◽  
...  

Winter cereal trials consisting of 10 cultivars representing cold hardiness potentials ranging up to the hardiness of Frontier winter rye were seeded at test sites throughout Saskatchewan for 2 yr. At most sites in the Brown soil zone only winter rye survived without extensive winter damage. At sites in the Black and Gray soil zones, winter survival was sufficient to provide agronomic data for several winter wheat cultivars. Considerable yield compensation took place in stands exhibiting partial winterkill, and as a result hardier cultivars did not always demonstrate a yield advantage.


1968 ◽  
Vol 48 (4) ◽  
pp. 369-376 ◽  
Author(s):  
D. W. A. Roberts ◽  
M. N. Grant

The cold resistance of 18 varieties of winter wheat hardened in a growth chamber was studied at various stages of development and the results were compared with the field survival of these varieties.In the growth chamber two maxima of cold resistance were found, the first for the dry or freshly moistened seed and the second when plants had approximately 4 to 6 leaves. Varietal differences were found in the exact timing of this second maximum and in its duration. As a result, some varieties changed their rank for cold resistance as they developed.Partial agreement was observed between the field survival of varieties sown at different dates and the changes in cold resistance of these varieties as they developed in the growth chamber.From these tests, a procedure has been developed that should enable fairly reliable predictions to be made of field survival of winter wheat in any area where low-temperature resistance is the major factor in winter survival.


1986 ◽  
Vol 66 (1) ◽  
pp. 25-37 ◽  
Author(s):  
C. J. ANDREWS ◽  
M. K. POMEROY ◽  
W. L. SEAMAN

A study was made from 1979 to 1982 of the overwintering capacity of winter cereals at six sites in eastern Ontario outside the traditional winter wheat growing area. Cultivars of soft white, soft and hard red wheats, a rye and a triticale were compared for winter survival in the field, cold hardiness and ice tolerance of plants removed from the field in winter, and grain yield. Overall mean grain yield of four wheats was the equivalent of 3980 kg/ha with a high mean yield of Houser in 1982 of 5035 kg/ha. In 3 yr good survival and yields were obtained with a range of cultivars, while in the fourth year only the hardiest cultivars survived well at most sites. Survival was reduced at one site in all 4 yr by snow mold. There were significant cultivar × site interactions in winter survival in 3 of the 4 yr. Fall-developed cold hardiness showed significant differences between sites and between cultivars with site means ranging from LD50 values of −20.6 °C to −10.2 °C. There were major differences in cold hardiness and ice tolerance of field-grown plants of 23 cultivars at Ottawa in 1981, but correlations between the two parameters were not significant. Ice tolerance in winter 1982 showed significant differences between sites and between cultivars. Winter survival and cold hardiness were significantly correlated at two of the five sites in 1982 — the most stressful winter season. Overall, Norstar, the highest winter survivor of the wheats, was frequently the lowest yielder. The red wheats Lennox and Valor showed consistenty high cold hardiness and winter survival accompanied by good yields, while of the soft white wheats, Houser showed frequent superiority in cold hardiness, and inconsistent advantages in winter survival and yield.Key words: Wheat (winter), winter injury, survival, cold hardiness, ice


1981 ◽  
Vol 61 (2) ◽  
pp. 225-230 ◽  
Author(s):  
D. B. FOWLER

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.


1997 ◽  
Vol 77 (4) ◽  
pp. 507-513 ◽  
Author(s):  
C. J. Andrews ◽  
M. K. Pomeroy ◽  
W. L. Seaman ◽  
G. Butler ◽  
P. C. Bonn ◽  
...  

Reduction of populations of fall planted crops in the course of winter can result in substantial losses in economic yield. Variations in planting date of soft white winter wheat (Triticum aestivum L.) in eastern Ontario are known to influence both survival and grain yield. This study was conducted to determine relationships between fall-accumulated growing degree days (GDD), cold hardiness, ice tolerance and a number of plant characteristics with survival recorded the next spring. Locations were at Ottawa (45°23′N) and Douglas (45°33′N) with four planting dates, 27 August, 10 September, 24 September and 8 October in 4 yr, 1983–1986. Delayed planting was associated with reduced survival at Ottawa in 1987 and in all years at Douglas. Consequently, survival at Ottawa showed little association with cold hardiness and ice tolerance, but there were significant correlations at Douglas. Measurements in 3 yr showed that late planted wheats were single tillered, up to 10 times lower fresh weight than the 3–5 tillered August-planted wheat, and their cold hardiness and ice tolerance were decreased. Moisture content of the crown tissue (CrW) increased with delayed planting despite the growth of the plants in acclimating conditions. Highest CrW developed in late-planted wheat at Douglas and showed a high negative correlation with survival. Cold hardiness and ice tolerance correlated with survival at Douglas and there were significant relationships between the stress tolerances. However, no consistent associations across location-years could be defined to explain winter survival in terms of fall-measured stress tolerances and plant parameters. Key words: Cold acclimation, cold hardiness, crown moisture, winter injury, ice encasement, delayed planting


1990 ◽  
Vol 70 (4) ◽  
pp. 1033-1041 ◽  
Author(s):  
J. B. THOMAS ◽  
R. A. BUTTS

Russian wheat aphid (RWA) (Diruaphis noxia (Mordvilko)) is a new and cold-hardy pest of temperate cereals in western Canada. In view of the risk of fall infestation of winter wheat (Triticum aestivum L. em. Thell.), this study was made to establish whether feeding by RWA can interfere with cold hardening and plant survival of overwintering winter wheat. Feeding by RWA significantly increased the LT50 of field-hardened Norstar winter wheat by + 2 to + 4 °C. Application of 400 g (a.i.) ha−1 of the insecticide chlorpyrifos in mid-October to control severe RWA infestations in two different fields of Norstar winter wheat significantly improved winter survival of the crop. The pattern of winterkill within the two fields suggested that this protective effect of chlorpyrifos was greatest in areas where microtopography resulted in the least accumulations of snow and cold stress was most intense. It was concluded that heavy RWA infestation in the fall significantly reduced freezing tolerance of winter wheat and increased the likelihood of winterkilling of the crop by severe cold.Key words: Winter survival, cold hardening, Diuraphis noxia, insecticide, chlorpyrifos, Triticum aestivum, crop damage


Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 453-456
Author(s):  
R S Zemetra ◽  
R Morris

Abstract During a study on the genetic control of winterhardiness in winter wheat (Triticum aestivum L. group aestivum), a gene that affected vernalization was found on chromosome 3B in the winter wheat cultivar ;Wichita.' When chromosome 3B from Wichita was substituted into the winter wheat cultivar ;Cheyenne,' the resultant substitution line exhibited a spring growth habit. This is unusual since a cross between the cultivars Wichita and Cheyenne results in progeny that exhibit the winter growth habit. The F(2) plants from a cross of the 3B substitution line to Cheyenne, the recipient parent, segregated 3:1 for heading/no heading response in the absence of vernalization (chi(2) = 2.44). Earliness of heading appeared to be due to an additive effect of the 3B gene as shown by the segregation ratio 1:2:1 (early heading-later heading-no heading) (chi(2) = 2.74). This vernalization gene differs from previously described vernalization genes because, while dominant in a Cheyenne background, its expression is suppressed in Wichita. The gene may have an effect on winter hardiness in Wichita. In a field test for winter survival the 3B substitution line had only 5% survival, while Wichita and Cheyenne had 50 and 80% survival, respectively. No other substitution line significantly reduced winter survival. The difference between Wichita and Cheyenne in winterhardiness may be due to the vernalization gene carried on the 3B chromosome.


1989 ◽  
Vol 19 (6) ◽  
pp. 773-782 ◽  
Author(s):  
Michel A. Campagna ◽  
Hank A. Margolis

Black spruce seedlings (Piceamariana Mill.) were exposed to either elevated (1000 ppm) or ambient (340 ppm) atmospheric CO2 levels at different stages of seedling development over a winter greenhouse production cycle. Seedlings germinated in early February and were placed in CO2 chambers for either 3 or 6 weeks during March, April, May, or August. Total seedling biomass increased under high CO2 conditions for the March, April, and May stages of development, but showed no significant response in August. The greater part of the CO2 response occurred during the second 3 weeks of exposure in March and April but during the first 3 weeks of exposure in May. In September, those seedlings exposed to CO2 in April and May had 30 and 14%, respectively, greater biomass than control seedlings, but seedlings from the other stages of development no longer had significant differences remaining from the CO2 treatment. This suggests that it could be very efficient to give a short well-timed CO2 pulse at the beginning of the production cycle in hopes of producing a size difference that is maintained throughout the remainder of the greenhouse production cycle under ambient levels of CO2. Short-term exposure to elevated CO2 also increased the ratio of shoot dry weight to total height for the March, April, and May stages of development. The ratio of total nonstructural carbohydrates to free amino acids was negatively correlated (r2 = 0.98) with the allocation of new growth between shoots and roots as measured by the allocation coefficient, k (milligrams shoot growth per milligrams root growth). As seedlings developed along their seasonal growth cycle, ratios of total nonstructural carbohydrates to free amino acids increased and the values for k decreased. The effect of CO2 enrichment on these two factors is discussed. Monitoring total nonstructural carbohydrate and free amino acid concentrations in foliage could have potential as a method to predict the percentage of carbon allocated to root systems of entire forest stands as well as of individual tree seedlings.


1996 ◽  
Vol 74 (6) ◽  
pp. 965-970 ◽  
Author(s):  
R. C. Fialho ◽  
J. Bücker

Specimens of Populus nigra L. cv. Loenen exhibit premature leaf senescence when exposed for a few weeks to realistic air pollution. In this study, the changes in levels of foliar carbohydrates and myo-inositol (MI) due to 30 ± 1 nL/L O3 + 12 ± 1 nL/L SO2 from the onset of exposure to the occurrence of premature abscission is presented. Petioles and laminae of the 12 oldest leaves were separately analysed on days 0, 4, 8, 12, 16, 20, 22, and 32 of continuous exposure, which was performed in open-top chambers (OTC). On days 8 to 12, clearly prior to yellowing (starting on day 22), total nonstructural carbohydrates (TNC; starch + raffinose + sucrose + glucose + fructose + MI) in the fumigated laminae exceeded that in controls by about 30%. This increase was due to higher amounts of different soluble forms, while starch remained unaltered. From day 20 onwards, the level of TNC in the fumigated laminae progressively fell below that in controls. This decrease was due to a progressive decline in starch, which had started on day 16 and was dominating, although glucose and raffinose increased significantly. In the petioles, starch, sucrose, and glucose decreased because of fumigation with the occurrence of leaf yellowing, while raffinose increased. In contrast, MI in the petioles progressively accumulated directly on exposure until leaf yellowing occurred. The results are discussed in terms of the "general adaption syndrome" of H. Selye (1936. Nature (London), 138: 32). The marked MI response in petioles is concluded to be an early indication of phytorelevant O3 + SO2 pollution. Keywords: air pollution, carbohydrates, myo-inositol, pigments, Populus nigra L., senescence, stress.


Sign in / Sign up

Export Citation Format

Share Document