Relationships between planting date, winter survival and stress tolerances of soft white winter wheat in eastern Ontario

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

1992 ◽  
Vol 72 (2) ◽  
pp. 391-402 ◽  
Author(s):  
C. J. Andrews ◽  
M. K. Pomeroy ◽  
W. L. Seaman ◽  
G. Hoekstra

A study was made to determine optimum fall planting dates and rates of seeding of soft white winter wheat (Triticum aestivum L.) in three counties in eastern Ontario. This area is considered marginal for winter survival of the crop, although yield potential is high. Plots were sown at Douglas (lat. 45°33′), Ottawa (lat. 45°23′) and Kemptville (lat. 45°00′). Four planting dates were used at Douglas and Ottawa (dates 1 to 4) and five dates at Kemptville. These were: date 1, 27 August; date 2, 10 September; date 3, 24 September; date 4, 8 October; and date 5, 22 October. Split-plot designs were used, with dates as main plots and with rates and cultivars randomized as subplots. Harvest years were between 1983 and 1987. Winter survival was generally reduced below 60% in later plantings, but survival remained high from the date 4 planting in two years at Ottawa. Grain yields were increased by early plantings. Maximum yields at Douglas were obtained from dates 1 and 2; at Ottawa and Kemptville, from dates 1 to 3. A significant advantage of date 2 planting was recorded at Kemptville. Kernel weight and test weight were reduced by late planting dates. Grain yields and winter survival were highly correlated at seven of nine location-years. At Ottawa, there was a significant yield increase from the 160 kg ha−1 seeding rate, compared with 130 kg ha−1, the currently recommended rate. Yield increases from higher seeding rates were greater at later planting dates. Cultivar effects on grain yields were frequently significant, but were less so on winter survival. The cultivar Houser produced the highest yield in five of nine location-years.Key words: Winter survival, wheat (winter), sowing date, sowing rate


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


1983 ◽  
Vol 63 (2) ◽  
pp. 429-435 ◽  
Author(s):  
C. J. ANDREWS ◽  
B. E. GUDLEIFSSON

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


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.


1975 ◽  
Vol 55 (2) ◽  
pp. 529-535 ◽  
Author(s):  
M. K. POMEROY ◽  
C. J. ANDREWS ◽  
G. FEDAK

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.


1990 ◽  
Vol 70 (2) ◽  
pp. 443-454 ◽  
Author(s):  
P. RICHARD HETHERINGTON ◽  
BRYAN D. McKERSIE ◽  
LISA C. KEELER

Two winter wheat (Triticum aestivum L.) cultivars, Fredrick and Norstar, which differ in their winterhardiness potential, were compared with regard to the effects of nitrogen (N), phosphorus (P) and potassium (K) application, during acclimation, on the expression of four traits associated with winterhardiness — freezing, ice-encasement, and low temperature flooding tolerances and crown moisture content. Modified Hoagland’s nutrient solutions containing five levels of each nutrient were applied to the seedlings during a 5-wk acclimation period at 2 °C, and subsequently the crowns were tested for their ability to survive varying intensities of the stress treatments. Increasing the level of applied N from 0, caused a reduction in the level of all stress tolerances. Increased P did not significantly alter the expression of freezing tolerance, but tended to increase tolerance of the anaerobic stresses, icing and low temperature flooding, to an optimum. Increased K had minimal effects on stress tolerance at the levels tested. Increased levels of each nutrient increased crown moisture content. The cultivar Norstar was consistently more tolerant of freezing and icing stress than Fredrick and this relative ranking was not influenced by mineral nutrition. However, the relative ranking for low temperature flooding tolerance varied depending on the nutrients provided to the seedlings. The results suggest that environmental and growth regulatory factors which influence the uptake of mineral nutrients would be expected to influence crown moisture content, and the expression of stress tolerance.Key words: Freezing, ice-encasement, flooding


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.


1978 ◽  
Vol 56 (7) ◽  
pp. 786-794 ◽  
Author(s):  
M. Keith Pomeroy ◽  
Chris J. Andrews

The decline in viability of cold-hardy Kharkov winter wheat (Triticum aestivum L.) seedlings during ice encasement at −1 °C was accompanied by characteristic ultrastructural changes. A dramatic increase in endoplasmic reticulum was observed within a few days. This proliferation of endoplasmic reticulum often resulted in the formation of an elaborate series of parallel membranes, either dispersed randomly throughout the cytoplasm or in the form of concentric whorls. However, the structural integrity of many cellular organelles was largely unaffected even by prolonged ice encasement resulting in death of the plants. In contrast, exposure of cold-hardy seedlings to near lethal, subfreezing temperature resulted in severe disorganization of cellular organelles. Ice encasement of nonhardened seedlings resulted in complete kill within 4 h. After 16 h ice encasement, occasional concentric whorls of endoplasmic reticulum and copious amounts of osmiophilic material were observed in the cytoplasm. Upon removal of the ice encasement stress, the accumulated endoplasmic reticulum disappeared rapidly during recovery at either2 or20 °C.


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