THE EFFECT OF IRRIGATION TIMING ON YIELD AND YIELD COMPONENTS OF WINTER WHEAT

1983 ◽  
Vol 63 (4) ◽  
pp. 815-823 ◽  
Author(s):  
M. L. HOOKER ◽  
S. H. MOHIUDDIN ◽  
E. T. KANEMASU

A study was conducted in southwest Kansas to evaluate the effect of limited water applications at critical growth stages on yield and yield components of winter wheat (Triticum aestivum L.). The experiment was a split-plot design. Irrigation treatments were main plots and cultivar × seeding rate combinations were subplots. The irrigation treatments were: Preplant (PP), PP + jointing (JT), PP + flowering (FL), and PP + JT + FL. Two cultivars (Centurk and Newton) were seeded at rates of 22, 45, and 67 kg∙ha−1. The experiment was conducted over a 2-yr period. During the first cropping season grain and straw yields showed a significant (P < 0.05), positive response to irrigation water applications at the JT growth stage, compared to the PP and PP + FL treatments. There was no significant effect of water treatments on heads per square metre, kernels per square metre or kernel weight. The second cropping season resulted in a positive, significant response of straw yields to irrigation treatments, but no significant response of grain. Grain yield response was nullified by greater kernel weight on the treatments that were most limiting in soil water during early reproductive development (PP and PP + FL).Key words: Triticum aestivum L., limited irrigation, moisture stress, seeding rate, kernel number, kernel weight

1977 ◽  
Vol 57 (3) ◽  
pp. 1005-1007 ◽  
Author(s):  
R. J. BAKER

Yield and yield components were measured on two spring wheat (Triticum aestivum L. em Thell) cultivars, Neepawa and Pitic 62, and a 1:1 mixture of the two sown at five rates of seeding in each of 2 yr. Lack of agreement between performance in pure and mixed stands was observed when, at the highest seeding rate, the mixture yielded higher in 1974 and lower in 1976 than either of the component cultivars grown in pure stand.


2000 ◽  
Vol 80 (4) ◽  
pp. 703-711 ◽  
Author(s):  
D. Spaner ◽  
A. G. Todd ◽  
D. B. McKenzie

Livestock farmers in Newfoundland presently import most of their feed grain, and local self-sufficiency in grain production is a desirable long-term goal. The overall objective of this work was to refine our understanding of winter wheat (Triticum aestivum L.) production in Newfoundland, with the aim of improving present cropping recommendations. We conducted trials near St. John's in 1998 and 1999 to examine the effect of seeding rate and topdress ammonium nitrate (N) fertilization rate on Borden winter wheat yield and yield components. We also conducted four seeding date trials in the same region. Optimum-treatment grain yields in our six trials ranged from 2.76 to 5.39 t ha−1. In years of variable winter kill, increasing seeding rate up to 450 seeds m−2 increased spikes m−2 at harvest, resulting in increased grain yield. Seeding rate, however, was not as important as N fertilization in maximizing grain yield. Increasing topdress fertilization to 60 kg N ha–1 increased spikes m–2 at harvest in years of variable winter kill, resulting in greater grain yield. In years of high winter survival, the main source of higher grain yield levels (through higher N application rates) was not achieved through greater spikes m−2 at harvest, but rather through an increase in kernel weight. Optimum grain yields occurred at seeding rates of 400 ± 50 seeds m−2, and at topdress fertilizer applications up to a rate of at least 30 kg N ha−1. Given the results of our seeding date experiments, in conjunction with previously developed climatic models, we now consider the optimum seeding date for the eastern region of Newfoundland to be August 31. Key words: Yield component analysis, two-dimensional partitioning, Triticum aestivum L., ammonium nitrate


1975 ◽  
Vol 55 (2) ◽  
pp. 363-367 ◽  
Author(s):  
K. G. BRIGGS

Three cultivars of wheat (Triticum aestivum L. em Thell.), Glenlea, Pitic 62 and Neepawa, were grown in a seeding rate and row spacing experiment at two locations in 1972 and 1973. In a split-plot design, row spacings of 15, 23 and 30 cm were used as main plots, and subplot seeding rates of 33.6, 67.3 and 100.9 kg/ha were applied for each cultivar. Data were collected on yield, days to maturity, plant height, lodging, kernel weight and test weight. The few significant effects of row spacing indicated that narrow row spacings tend to increase yield and decrease days to maturity. Higher seeding rates per unit area generally resulted in higher yields for all cultivars and, to some extent, earlier maturity. Glenlea wheat seeded at 100.9 kg/ha gave the highest yield in all tests, and at this seeding rate took an average 125 days to reach maturity, compared to 120 days for Neepawa and 129 days for Pitic 62. Seeding rate had virtually no effect on height, kernel weight or test weight of any of the wheats.


1979 ◽  
Vol 59 (4) ◽  
pp. 939-943 ◽  
Author(s):  
A. E. SMID ◽  
R. C. JENKINSON

Two cultivars of soft white winter wheat, Fredrick and Yorkstar, were sown at rates of 34, 67, 101, 134 and 168 kg/ha on or near 24 Sept., 9 Oct. and 23 Oct. in each of the 3 yr 1973–1975, at Ridgetown, Ontario. Highest net yields were obtained with rate of seeding 134 kg/ha. Seeding rate did not affect lodging. Yield per hectare and spikes per hectare were positively correlated while kernels per spike and spikes per hectare were negatively correlated. However, as the rate of seeding was increased, the increase in the number of spikes per hectare was greater than the accompanying decrease in kernels per spike, resulting in a net overall increase in yield. Highest yields of Fredrick were obtained near 9 Oct. and those of Yorkstar near 24 Sept. Yields decreased more rapidly with delayed seeding when seeding rates were less than 134 kg/ha, especially with Yorkstar. Test weight of Yorkstar was low, especially when sown late. Fredrick yielded 3–25% more than Yorkstar. A delay in seeding beyond 9 Oct. resulted in a yield reduction of 23 kg/ha/day. Fredrick should be sown instead of Yorkstar when seeding is delayed beyond recommended dates of seeding.


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