RELATIONSHIPS AMONG TILLERING, SPIKE NUMBER AND GRAIN YIELD IN WINTER WHEAT (Triticum aestivum L.) IN ONTARIO

1988 ◽  
Vol 68 (3) ◽  
pp. 583-596 ◽  
Author(s):  
P. BULMAN ◽  
L. A. HUNT

Two field experiments were conducted to examine the relationships between tillering, spike number and grain yield in three winter wheat (Triticum aestivum L.) cultivars. Treatments were designed to manipulate both the production and survival of tillers, and to provide a high number of spikes per unit area. One experiment involved growth regulator treatments with cycocel and gibberellic acid while the second involved various rates of nitrogen. Grain yield was linearly related to total spike number over a range of 400–1200 spikes m−2 in a combined analysis over locations and years. When only spikes with at least nine fertile spikelets were included, a greater amount of the variability in yield could be explained, and differences among cultivars were related to the number of small, unproductive spikes. When locations and years were analyzed separately, little evidence was found for a diminishing response between grain yield and total spike number. Spike number was related to maximum tiller number in 1982, when winterkill and early spring conditions were unfavorable. Thus, although good fall tillering and winter survival contribute most to producing high spike numbers and grain yield, cultivars must also have the ability both to tiller rapidly in the spring and to sustain high-yielding tillers to provide sufficient compensation following winterkill.Key words: tillering, spikes, yield, wheat, nitrogen, regulators

1989 ◽  
Vol 69 (3) ◽  
pp. 881-888 ◽  
Author(s):  
D. A. DERKSEN ◽  
K. J. KIRKLAND ◽  
B. R. McLENNAN ◽  
J. H. HUNTER ◽  
H. A. LOEPPKY ◽  
...  

Recommendations regarding the timing of herbicide application in winter wheat vary among production areas. The current increase in area of winter wheat production in Saskatchewan warrants an examination of herbicide recommendations for this non-traditional production area. Field research was conducted for 2 yr at several locations in Saskatchewan using 2,4-D, MCPA, dicamba, bromoxynil, chlorsulfuron, and clopyralid, applied in the late fall or early spring, to determine the effects of time and rate of application on winter wheat grain yield. Winter wheat (Triticum aestivum L. ’Norstar’) was tolerant to fall application of all herbicides at rates recommended for spring application. Grain yield was reduced in some cases when double the recommended spring rate of 2,4-D, MCPA, bromoxynil, and clopyralid was applied in the fall. Spring application of clopyralid resulted in significantly lower grain yield than fall application. All herbicides tested show potential for use in winter wheat production, although caution is warranted for spring application of clopyralid.Key words: Wheat (winter), 2,4-D, MCPA, dicamba, bromoxynil, chlorsulfuron


2004 ◽  
Vol 84 (1) ◽  
pp. 125-131 ◽  
Author(s):  
A. B. Middleton ◽  
E. Bremer ◽  
R. H. McKenzie

The recommended method for N fertilization to winter wheat (Triticum aestivum L.) on the Canadian prairies has been to broadcast ammonium nitrate (AN) during early spring. In the Chinook region of southern Alberta, considerable interest exists in alternative formulations (particularly urea), times of application and placements. To determine the effect of alternative N fertilizer practices on winter wheat in southern Alberta, two field experiments were conducted over 2 consecutive years (1998-1999 and 1999-2000) at three locations. In the first experiment, fall applications of urea or coated urea, seed-placed or banded, were compared to the standard practice of spring-broadcast AN. At five of six sites, there was no difference between fall-banded urea and coated urea in plant stand, grain yield or protein concentrations when compared to spring-broadcast AN. In 1998-1999, fall-banded urea reduced grain yield by 13% at the site in the Brown soil. Seed-placed N was only safe for urea at 30 kg N ha-1 and for coated urea at rates up to 60 kg N ha-1. In the second experiment, urea and coated urea were broadcast in spring for comparison with AN. Coated urea was ineffective in dry years due to poor N release. Urea was equally effective as AN in this study, possibly due to the cool, dry conditions at the time of application and the relatively low surface soil pH levels at these reduced tillage sites. Further research will be required to confirm the effectiveness of this practice for this region. Key words: Ammonium nitrate, urea, coated urea, nitrogen fertilizer placement, nitrogen timing, grain protein


1990 ◽  
Vol 68 (7) ◽  
pp. 1597-1601 ◽  
Author(s):  
John S. Taylor ◽  
Munjeet K. Bhalla ◽  
J. Mason Robertson ◽  
Lu J. Piening

During overwintering in a northern climate, winter wheat goes through a hardening process, followed by dehardening in late winter – early spring. This sequence of events may be partially controlled by changes in endogenous hormone levels. Crowns and leaf tissue from field grown winter wheat (Triticum aestivum L. cv. Norstar) seeded at the beginning of September were collected and freeze-dried at monthly intervals during the winters of 1985–1986 and 1986–1987. Material was also sampled and freeze-dried from seedlings grown in a growth chamber under hardening conditions (21 °C for 2 weeks plus 3 °C for 6 weeks) or nonhardening conditions (3 weeks at 21 °C). The tissues were analysed for cytokinins and abscisic acid. Cytokinin levels, measured with the soybean hypocotyl section assay, declined from October onwards and then rose to a peak in late winter (January and February, winter 1986–1987; February and March, winter 1985–1986), subsequently declining again. Abscisic acid, quantitated as the methyl ester by gas chromatography with an electron capture detector, increased in level from October to December, then decreased to a relatively low level between January and March. Hardened seedlings from the growth chamber contained significantly higher abscisic acid levels and significantly lower cytokinin levels than did the nonhardened seedlings. Key words: abscisic acid, cytokinins, hardening, Triticum aestivum, winter wheat.


2016 ◽  
Vol 69 (3) ◽  
Author(s):  
Elżbieta Harasim ◽  
Marian Wesołowski ◽  
Cezary Kwiatkowski ◽  
Paweł Harasim ◽  
Mariola Staniak ◽  
...  

<p>The aim of the present study was to determine the effect of different growth regulator rates and nitrogen fertilization levels on yield components and to evaluate their influence on winter wheat productivity. A field experiment with winter wheat ‘Muza’ was conducted at the Czesławice Experimental Farm, belonging to the University of Life Sciences in Lublin, Poland over the period 2004–2007. In this experiment, the effect of the studied factors on yield and its components was primarily dependent on weather conditions during the study period.</p><p>An increase in nitrogen rate from 100 to 150 kg ha<sup>−1</sup> in 2005 and 2007 had a significant effect on the increase in grain yield per unit area. In 2005, the grain yield rose through increased spike density (by 6.3%) and a higher number of grains per spike (by 1.6%). The 1000-grain weight decreased the grain yield per unit area (by 0.04 t ha<sup>−1</sup>). In 2007, the higher yield of wheat fertilized with nitrogen at a rate of 150 kg N ha<sup>−1</sup> was positively affected by all the three yield components. The statistical analysis of the results showed that the winter wheat grain yields were also significantly affected by the retardant rates applied depending on the year.</p>


1989 ◽  
Vol 3 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Jill Schroeder ◽  
Philip A. Banks

Soft red winter wheat cultivars were evaluated in field experiments in Georgia for tolerance to dicamba alone and mixed with 2,4-D. Treatments reduced ‘Florida 302’ yield more than ‘Florida 301’ or ‘Coker 983’ at Tifton in 1986. Mid-tillering Florida 302 wheat was more sensitive to treatment than fully tillered wheat. In 1987, dicamba plus 2,4-D applied at mid-tillering reduced yields of all cultivars in Watkinsville. Injury and yield reductions occurred primarily when mid-tiller treatments were applied to wheat that was planted 10 or 21 days later than recommended at Tifton or Watkinsville, respectively. When applied according to labeling, dicamba or dicamba plus 2,4-D use in Georgia soft red winter wheat can reduce grain yield.


1988 ◽  
Vol 68 (2) ◽  
pp. 301-309 ◽  
Author(s):  
D. J. GILLILAND ◽  
D. B. FOWLER

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


2019 ◽  
Vol 50 (16) ◽  
pp. 2056-2064 ◽  
Author(s):  
Lawrence Aula ◽  
Peter Omara ◽  
Jagmandeep S. Dhillon ◽  
Alimamy Fornah ◽  
William R. Raun

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