A comparison of aerial and conventional methods for seeding winter wheat

Non-Peer Reviewe

A comparison of broadcast and conventional methods for seeding winter wheat in east central Saskatchewan

Non-Peer Reviewe

The pattern of nitrogen uptake in winter wheat

Non-Peer ReviewedThe pattern of nitrogen uptake was examined in Norstar winter wheat (Triticum aestivum L.) grown at several locations in Saskatchewan during a three-year period. Replicated field trials were supplemented with 0, 34, 67,100, and, in the final year, 200 kg of nitrogen per hectare applied as ammonium nitrate (34-0-0) in the early spring. Plant samples were collected at two-week intervals during the growing season and analyzed for dry matter yield, nitrogen concentration and plant nitrogen yield. Modified harvest and nitrogen harvest indexes were calculated by comparing the wheat heads to the total plant material. In general, nitrogen concentration of stems and leaves decreased during the growing season while changes in nitrogen concentration of the wheat heads were more dependent: on environmental conditions. Dry matter yield and plant nitrogen yield increased during the season. This increase tended to level off near maturity at some locations, especially when moisture conditions were low. When soil nitrogen levels were low, increased amounts of nitrogen fertilizer increased dry matter yield and yield of plant nitrogen per hectare but had no effect on plant nitrogen concentration. When soil nitrogen levels were high and soil moisture was adequate, addition of nitrogen fertilizer increased only plant nitrogen concentration. At some locations, plant stand variability was too large to detect differences among fertilizer treatments. At most locations there were no differences among the fertilizer rates for harvest and nitrogen harvest indexes, indicating that there was no change in plant efficiency with a change in available nitrogen

Prospects for improving grain protein concentration in winter wheat through plant breeding

Non-Peer ReviewedLow protein concentration has been a degrading factor for "stubbled-in" winter wheat. Genes for improved protein concentration have been reported in several foreign cultivars. This paper outlines the results of plant breeding efforts to incorporate these genes into a Norstar or related background. The interactions of these genes with the environment were also studied in field experiments conducted over a three-year period in Saskatchewan. Response of grain yield and protein concentration to applied nitrogen was similar for each cultivar studied but the highest yielding genotypes tended to have the lowest protein concentration. Heritability estimates for grain yield, protein concentration and protein yield were fairly high (0.47 to 0.75) but very large environmental effects can severely limit the effectiveness of selection for these traits in winter wheat

Effect of seeding rate and row spacing on the agronomic performance of winter wheat

Non-Peer ReviewedThe effect of row spacings and seed rates on the agronomic performance of "stubbled in" winter wheat (Triticum aestivum L.) were studied over a period of two years at locations in central, northeast, and southeast Saskatchewan. In both years of the study there was a highly significant relationship between row spacing and yield with increased yields at narrower row spacings. The yield response to seeding rate indicated different trends in each of the two years of the study. In 1985/86 there was a highly significant relationship between seed rate and yield with increased yields at higher seed rates. In 1986/87 the relationship between seeding rate and yield was not significant. In 1985/86 higher head counts/m2 at higher seeding rates resulted in the higher yields. In 1986/87 the head counts/m2 were also higher at higher seeding rates however a reduction in seeds/head and/or 1000k weight counteracted the effects of the higher head populations resulting in non-significant yield differences

The effect of hoe-opener design on draft forces of a minimum tillage hoe drill

Non-Peer Reviewe

Effect of seeding depth on the performance of winter wheat

Non-Peer Reviewe

Importance of granular nitrogen fertilizer applicator selection and adjustment when fertilizing for maximum economic yield of no-till winter wheat

Non-Peer Reviewe

Influence of climate and cultivar on grain protein concentration of wheat and rye

Non-Peer Reviewe

Constraints on the Variation of the Fine Structure Constant from Big Bang Nucleosynthesis

We put bounds on the variation of the value of the fine structure constant $\alpha$, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to $^7$Li. We correct a previous upper limit on $|\Delta \alpha / \alpha|$ estimated from $^4$He primordial abundance and we find interesting new potential limits (depending on the value of the baryon-to-photon ratio) from $^7$Li, whose production is governed to a large extent by Coulomb barriers. The presently unclear observational situation concerning the primordial abundances preclude a better limit than |\Delta \alpha/\alpha| \lsim 2\cdot 10^{-2}, two orders of magnitude less restrictive than previous bounds. In fact, each of the (mutually exclusive) scenarios of standard Big Bang nucleosynthesis proposed, one based on a high value of the measured deuterium primordial abundance and one based on a low value, may describe some aspects of data better if a change in $\alpha$ of this magnitude is assumed.Comment: 21 pages, eps figures embedded using epsfig macr