USE OF LETHAL DOSE TEMPERATURE ESTIMATES AS INDICES OF FROST TOLERANCE FOR WHEAT COLD ACCLIMATED UNDER NATURAL AND CONTROLLED ENVIRONMENTS

1973 ◽  
Vol 53 (3) ◽  
pp. 489-494 ◽  
Author(s):  
M. K. POMEROY ◽  
D. B. FOWLER

LD50 (lethal dose 50) temperature estimates were utilized to study cold acclimation in three winter and one spring wheat (Triticum aestivum L.) cultivars grown under natural and controlled environments. Highly significant differences were found among cultivars for both rate and maximum level of cold acclimation with the acclimation patterns being similar for both environments. The advantages and limitations to the use of lethal dose temperature ratings in cold hardiness studies are discussed.

Botany ◽  
2012 ◽  
Vol 90 (6) ◽  
pp. 433-444 ◽  
Author(s):  
Keshav Dahal ◽  
Khalil Kane ◽  
Fathey Sarhan ◽  
Bernard Grodzinski ◽  
Norman P.A. Hüner

We assessed the effects of short-term elevated CO2 on the light-saturated rates of photosynthesis (Asat) of spring (‘SR4A’, ‘Katepwa’) and winter (‘Musketeer’, ‘Norstar’) wheat ( Triticum aestivum L.) and rye ( Secale cereale L.) cultivars grown at ambient CO2 (380 µmol C·mol–1) at either 20/16 °C (nonacclimated, NA) or 5/5 °C (cold acclimated, CA). In spring wheat–rye, cold acclimation decreased CO2-stimulation of Asat by 45%–60% relative to NA controls following a short-term (80 h) shift of plants from ambient to elevated CO2 (700 µmol C·mol–1). In contrast, in winter wheat–rye, cold acclimation enhanced CO2-stimulation of Asat by 15%–35% relative to NA controls upon a shift to elevated CO2. The stimulation observed for CA spring cultivars was about 60% less than that of CA winter cultivars. We conclude that a short-term exposure of spring cultivars to elevated CO2 cannot compensate for the cold acclimation-induced inhibition of Asat. Cold acclimation of spring cultivars appeared to exacerbate Rubisco CO2 substrate limitations present under ambient CO2. Furthermore, CA spring cultivars were unable to adjust their short-term temperature sensitivity of Asat under elevated CO2 compared with the winter cultivars.


1986 ◽  
Vol 28 (6) ◽  
pp. 991-997 ◽  
Author(s):  
D. W. A. Roberts

'Rescue', 'Cadet', and the 42 reciprocal chromosome substitution lines derived from these two spring wheat cultivars were tested for vernalization response and cold hardiness. Cold hardiness was tested after hardening under a 16-h day for 8 weeks with 6 °C day and 4 °C night temperatures or in the dark for 7 weeks at 0.8 °C followed by 8 weeks at −5 °C. Chromosomes 5A, 5B, 7B, and possibly 2A carried loci for vernalization response. Chromosomes 2A, 5A, and 5B carried loci affecting cold hardiness measured after 8 weeks in the light at 6 °C during the day and 4 °C at night, whereas chromosomes 6A, 3B, 5B, and 5D were involved in cold hardiness after hardening in the dark at 0.8 °C followed by −5 °C. The results suggest that the rank order of cultivars for cold hardiness depends on the hardening technique used since the two different techniques tested had different genetic and presumably somewhat different biochemical bases.Key words: Triticum aestivum L., cold hardiness, vernalization.


1983 ◽  
Vol 63 (4) ◽  
pp. 879-888 ◽  
Author(s):  
W. G. LEGGE ◽  
D. B. FOWLER ◽  
L. V. GUSTA

The cold hardiness of tillers separated from the plant immediately before freezing (CTM) or left intact on the crown (ICM) was determined by artificial freeze tests on two sampling dates for four winter wheat (Triticum aestivum L.) cultivars acclimated in the field. Plants with 9 and 13 tillers excluding coleoptile tillers were selected in mid-October and at the end of October, respectively. No differences in lethal dose temperature (LT50) were detected among CTM or ICM tillers sampled in mid-October. The three youngest CTM tillers sampled at the end of October were less cold hardy than older tillers. However, younger CTM tillers did not survive the unfrozen control treatment as well as older tillers. ICM tillers sampled at the end of October had the same LT50 except for one of the older tillers. No correlation was found between either the moisture content or dry weight and the LT50 of tillers. Winter survival of tillers was evaluated for two cultivars in the spring. Tillers of intermediate age and two of the youngest tillers had the highest survival rates. Tiller regeneration from axillary buds rather than the apical meristem occurred following cold stress and was negatively correlated to tiller emergence date. It was concluded that differences in cold hardiness among tillers must be taken into consideration if tillers are utilized to estimate the LT50 of a plant.Key words: Cold hardiness, tillers, winter wheat, Triticum aestivum L., developmental stage, moisture content


2019 ◽  
Vol 132 (11) ◽  
pp. 3023-3033 ◽  
Author(s):  
Firdissa E. Bokore ◽  
Richard D. Cuthbert ◽  
Ron E. Knox ◽  
Arti Singh ◽  
Heather L. Campbell ◽  
...  

1991 ◽  
Vol 71 (2) ◽  
pp. 519-522 ◽  
Author(s):  
R. M. DePauw ◽  
K. R. Preston ◽  
T. F. Townley-Smith ◽  
E. A. Hurd ◽  
G. E. McCrystal ◽  
...  

Biggar red spring wheat (Triticum aestivum L.) combines high grain yield potential with semidwarf stature and wide adaptation. Biggar has improved end-use suitability relative to HY320 such as harder kernels, better flour milling properties, greater water absorption, and stronger gluten properties. It received registration No. 3089 and is eligible for grades of Canada Prairie Spring (red). Key words: Triticum aestivum, wheat (spring), high yield, cultivar description


1990 ◽  
Vol 70 (1) ◽  
pp. 51-60 ◽  
Author(s):  
D. T. GEHL ◽  
L. D. BAILEY ◽  
C. A. GRANT ◽  
J. M. SADLER

A 3-yr study was conducted on three Orthic Black Chernozemic soils to determine the effects of incremental N fertilization on grain yield and dry matter accumulation and distribution of six spring wheat (Triticum aestivum L.) cultivars. Urea (46–0–0) was sidebanded at seeding in 40 kg N ha−1 increments from 0 to 240 kg ha−1 in the first year and from 0 to 200 kg ha−1 in the 2 subsequent years. Nitrogen fertilization increased the grain and straw yields of all cultivars in each experiment. The predominant factor affecting the N response and harvest index of each cultivar was available moisture. At two of the three sites, 91% of the interexperiment variability in mean maximum grain yield was explained by variation in root zone moisture at seeding. Mean maximum total dry matter varied by less than 12% among cultivars, but mean maximum grain yield varied by more than 30%. Three semidwarf cultivars, HY 320, Marshall and Solar, had consistently higher grain yield and grain yield response to N than Glenlea and Katepwa, two standard height cultivars, and Len, a semidwarf. The mean maximum grain yield of HY 320 was the highest of the cultivars on test and those of Katepwa and Len the lowest. Len produced the least straw and total dry matter. The level of N fertilization at maximum grain yield varied among cultivars, sites and years. Marshall and Solar required the highest and Len the lowest N rates to achieve maximum grain yield. The year-to-year variation in rates of N fertilization needed to produce maximum grain yield on a specific soil type revealed the limitations of N fertility recommendations based on "average" amounts and temporal distribution of available moisture.Key words: Wheat (spring), N response, standard height, semidwarf, grain yield


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.


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