bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of short-lived perennial grasses grown with and without alfalfa at a semiarid location in southern Saskatchewan
Authors: Jefferson P. G. , Zentner R. P. , Selles F. , Lemke R.
Published: April 2011

Tyically, crop rotations in the semiarid region of the Canadian prairies do not include perennial forages because forage termination produces negative effects on subsequent annual crops. Three short-lived perennial grass species, Dahurian wildrye grass (Elymus dahuricus Turcz. Ex Griseb), intermediate wheatgrass [Elytrigia intermedia (Host) Nevski] and slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners), were compared for their forage productivity and persistence as short duration (3 yr) forage stands, either in a mixture with alfalfa (Medicago sativa L.) or in monoculture, in three trials at Swift Current, Saskatchewan. Intermediate wheatgrass produced 29 and 22% more forage and was more persistent than Dahurian wildrye or slender wheatgrass, respectively. In alfalfa mixtures, however, the grasses produced similar forage yield in two of three trials. Intermediate wheatgrass was more persistent in mixtures but yield compensation by alfalfa grown with Dahurian wildrye and slender wheatgrass produced similar total forage yield as these grass stands thinned during the third year of each trial. Intermediate wheatgrass and alfalfa mixtures could be utilized for short rotation forage stands in high-input crop sequences where stand termination is achieved with herbicides. Dahurian wildrye and alfalfa mixture has the best potential for short-rotation forages in organic crop systems of this region because it would require less tillage to terminate the stand. Key words: Crop rotation, forage yield
Biomass and yield performance of kabuli chickpea cultivars with the fern or unifoliate leaf trait in the Northern Great Plains
Authors: Li Lin , Bueckert Rosalind A , Gan Yantai , Warkentin Tom
Published: April 2011

Chickpea (Cicer arietinum L.) has two kinds of leaf types, the fern and unifoliate. The best leaf type to use for biomass production and yield in the short growing season of the Northern Great Plains, which has a semiarid environment with end of season rainfall, is not yet known. The objectives of this research were to determine the relationships between leaf type and crop growth rate, maximum above-ground biomass, harvest index and yield under moderate and high plant population densities. The study was conducted in the field at Saskatoon and Swift Current, Saskatchewan, in 2003 and 2004. The experimental treatments consisted of a factorial combination of six commercial kabuli chickpea cultivars representing the two leaf types and two plant population densities: 45 and 85 plants m-2. There were no cultivar and plant population interactions for crop growth rate, maximum above-ground biomass, harvest index and seed yield. Dry matter production was higher in the 2004 season, which had above-average rainfall and a longer duration of reproductive growth. Although high plant population exhibited higher maximum above-ground biomass in 3 location-years, plant population did not affect the crop growth rate. The 45 plants m-2 treatment had a higher harvest index than the 85 plants m-2 treatment in 2 location-years, but both population treatments were similar in the other two environments. Yield of chickpea was increased by higher plant population in 1 location-year, but was not affected by plant population in the other location-years. The fern leaf cultivars had a higher crop growth rate over the unifoliate leaf cultivars in 2 location-years and no significant difference in the other environment. Fern-leaf cultivars partitioned more dry matter to seed growth compared with unifoliate cultivars while sustaining similar biomass production as unifoliate cultivars. The use of fern-leaf cultivars in the Northern Great Plains appears to be an opportunity for increasing chickpea yield by its superior harvest index compared with unifoliate leaf cultivars. Key words: Cicer arietinum, fern leaf, unifoliate, plant population, seed yield
Biplot analysis of multi-environment trial data: Principles and applications
Authors: Yan Weikai , Tinker Nicholas A.
Published: April 2011

Biplot analysis has evolved into an important statistical tool in plant breeding and agricultural research. Here we review the basic principles of biplot analysis and recent developments in its application in analyzing multi-environment trail (MET) data, with the aim of providing a working guide for breeders, agronomists, and other agricultural scientists on biplot analysis and interpretation. The review is divided into four sections. The first section is a complete but succinct description of the principles of biplot analysis. The second section is a detailed treatment of biplot analysis of genotype by environment data. It addresses environment and genotype evaluation from all perspectives. The third section deals with biplot analysis of various two-way tables that can be generated from a three-way MET dataset, which is an integral and essential part to a fuller understanding and exploration of MET data. The final section discusses questions that are frequently asked about biplot analysis. Methods described in this review are available in a user-friendly, interactive software package called “GGEbiplot”. Key words: biplot analysis; genotype by environment interaction; mega-environment; multi-environment trials
A decade of herbicide-resistant crops in Canada
Authors: Beckie H. J. , Harker K. N. , Hall L. M. , Warwick S. I. , Légère A. , Sikkema P. H. , Clayton G. W. , Thomas A. G. , Leeson J. Y. , Séguin-Swartz G. , Simard M. -J.
Published: April 2011

This review examines some agronomic, economic, and environmental impacts of herbicide-resistant (HR) canola, soybean, corn, and wheat in Canada after 10 yr of growing HR cultivars. The rapid adoption of HR canola and soybean suggests a net economic benefit to farmers. HR crops often have improved weed management, greater yields or economic returns, and similar or reduced environmental impact compared with their non-HR crop counterparts. There are no marked changes in volunteer weed problems associated with these crops, except in zero-tillage systems when glyphosate is used alone to control canola volunteers. Although gene flow from glyphosate-HR canola to wild populations of bird’s rape (Brassica rapa L.) in eastern Canada has been measured, enrichment of hybrid plants in such populations should only occur when and where herbicide selection pressure is applied. Weed shifts as a consequence of HR canola have been documented, but a reduction in weed species diversity has not been demonstrated. However, reliance on HR crops in rotations using the same mode-of-action herbicide and/or multiple in-crop herbicide applications over time can result in intense selection pressure for weed resistance and consequently, greater herbicide use in the future to control HR weed biotypes. History has repeatedly shown that cropping system diversity is the pillar of sustainable agriculture; stewardship of HR crops must adhere to this fundamental principle. Key words: Canola, Brassica napus, corn, Zea mays, soybean, Glycine max, wheat, Triticum aestivum, gene flow, herbicide resistance, transgenic crop, volunteer crop
The influence of seed size on soybean yield in short-season regions
Authors: Morrison Malcolm J , Xue A. G.
Published: April 2011

Two field experiments were done to determine if simple mechanical selection for seed size in soybean (Glycine max L. Merr.) could improve emergence and yield in short-season regions. Stacked screens with round holes 7.54, 7.14, 6.35 and 5.95 mm in diameter classified seeds into large, medium, small, and unscreened sizes. In exp. 1, small seeds resulted in lower yield than medium, large and unscreened seeds in two out of three cultivars, while in the third cultivar small seeds yielded less than the medium and large seed sizes, but were not significantly different from the unscreened size. In exp. 2, soil texture and seed size had a variable influence on seed emergence, which did not translate into consistent significant yield differences. Future research into mechanically removing small seeds from commercial seed lots is warranted in the short-season region. Key words: Seed size, soil texture, soybean, Glycine max L. Merr.
Genetic diversity in conventional and synthetic wheats with drought and salinity tolerance based on AFLP
Authors: Das M. K. , Bai G-H. , Mujeeb-Kazi A.
Published: April 2011

Genetic diversity among 14 drought tolerance (drought accessions) and 27 salinity tolerance (salinity accesions) related conventional and synthetic wheat (Triticum sp.) accessions containing different sources of the D genome was assessed using amplified fragment length polymorphism (AFLP). The wheat accessions were analyzed with 20 EcoRI/MseI primer combinations. Among 918 fragments scored, 368 were polymorphic across all 41 wheat accessions, 348 were polymorphic among the drought accessions and 310 were polymorphic among the salinity accessions. Similarity coefficients among all accessions based on Jaccard’s coefficient ranged from 0.18 to 0.92 with an average of 0.53 ± 0.01; among drought accessions, from 0.16 to 0.79 with an average of 0.43 ± 0.02; and among salinity accessions, from 0.16 to 0.92 with an average of 0.57 ± 0.01. Polymorphic information content (PIC) among all accessions ranged from 0.05 to 0.50 with an average PIC of 0.30 ± 0.01; among drought accessions, from 0.13 to 0.50 with an average PIC of 0.37 ± 0.01; and among salinity accessions, from 0.07 to 0.50 with an average PIC of 0.29 ± 0.01. Cluster and principal component analysis showed distinct groups of accessions both within drought and salinity entries. These accessions possess a substantial amount of genetic diversity and would be very valuable materials for breeding wheat with drought and salinity tolerance. Key words: AFLP, DNA fingerprinting, genetic diversity, synthetic wheat
Indirect selection for lower deoxynivalenol (DON) content in grain in a winter wheat population
Authors: Tamburic-Ilincic L. , Schaafsma A. W. , Falk D. E.
Published: April 2011

Selection for Fusarium head blight (FHB) resistance and lower deoxynivalenol (DON) content is an important goal in many wheat-breeding programs worldwide. Preliminary screening for less severe FHB symptoms in the early segregating generations can be an important tool to assist breeders in determining which lines to advance to homozygosity. The objectives of this study were: (1) to test influence of plant height, heading date, presence of awns and number of spikelets per spike on FHB index and DON content and (2) to estimate the reliability of indirect selection for lower DON content based on FHB index. A Ruby × Frontana winter wheat population was spray inoculated with a spore suspension of Fusarium graminearum in 2001 and 2002. Plant height was significantly associated with DON content in both years; taller lines accumulated less DON than shorter ones. The moderately resistant lines, based on FHB index after in oculation, had a statistically lower DON accumulation compared with the highly susceptible ones (17.7 ppm vs. 20.6 ppm and 0.6 ppm vs. 2.0 ppm in 2001 and 2002) respectively. The results from this study suggest that selection for FHB resistance can be an indirect selection method for lowering DON accumulation in wheat grain. A breeder can identify and discard those early generation lines that are highly susceptible to FHB as they likely would have higher DON levels. Key words: Fusarium graminearum (Schwabe), morphology, resistance, Triticum aestivum L.
Red River 1826 Roundup Ready™ high erucic acid, low glucosinolate summer rape
Authors: McVetty P. B. E. , Fernando W. G. D. , Scarth R. , Li G.
Published: April 2011

Red River 1826 summer rape (Brassica napus L.) is the world’s first Roundup Ready™ high erucic acid, low glucosinolate cultivar. It has an average 1% yield advantage over Reston high erucic acid, low glucosinolate summer rape, is 39 g kg-1 higher in seed oil content than Reston, 13 g kg-1 higher in meal protein content than Reston, and is adapted to the southern B. napus growing regions of western Canada. Key words: Rape, Roundup Ready™, high erucic acid, low glucosinolate, cultivar description
Characterizing sugarbeet varieties for postharvest storage losses is complicated by environmental effects and genotype × environment interactions
Authors: Campbell L. G. , Klotz K. L.
Published: April 2011

Each year millions of tons of sugarbeet (Beta vulgaris L.) roots are stored in large exposed piles prior to processing. During postharvest storage, respiration and invert sugar formation consume sucrose and even a small reduction in these losses would have substantial economic impact. This study investigated the relative importance of hybrid, environment, and hybrid × environment interactions and examined their implications in characterizing hybrids for sucrose loss during storage or developing hybrids with improved storage properties. Glucose, fructose, and extractable sucrose concentrations and respiration rate were measured 30 and 120 d after harvest (DAH) on five hybrids produced in six environments. Environment effects were significant on both dates for all traits except fructose 30 DAH. Significant hybrid × environment interactions were observed for respiration rate 30 and 120 DAH, for extractable sucrose 120 DAH, and for glucose concentration 30 DAH. The only trait with a significant hybrid main effect was extractable sucrose 30 DAH. For the 90 d between measurements, extractable sucrose losses for individual hybrid-environment combinations ranged from 1 to 63% of the sucrose available 30 DAH. It appeared that large environmental impacts and hybrid × environment interactions, compared to the relatively small hybrid influences, would complicate selecting parental lines with all or most of the storage traits desired. Furthermore, a comprehensive evaluation of commercial hybrids or breeding lines for storage traits would require considerable resources. Efforts to understand the impact of production practices and growing season environment on storage properties would probably be more productive than attempting to produce commercial hybrids with improved storage characteristics. Key words: Beta vulgaris L., respiration, glucose, fructose, extractable sucrose
Snowbird hard white spring wheat
Authors: Humphreys D. G. , Townley-Smith T. F. , Czarnecki E. , Lukow O. M. , McCallum B. , Fetch T. , Gilbert J. , Menzies J.
Published: April 2011

Snowbird is a hard white spring wheat (Triticum aestivum L.) that meets the end-use quality and kernel visual distinguishability specifications of the Canada Western Hard White Spring Wheat class. Snowbird was evaluated in the Central Bread Wheat Cooperative Test in 1998, 1999 and 2000, and was found to be adapted to the wheat-growing regions of the Canadian prairies. Snowbird yielded more than the check cultivars Neepawa, Roblin, AC Majestic, McKenzie, Harvest, and AC Barrie but less than McKenzie. Snowbird is resistant to the prevalent races of leaf rust and moderately resistant to stem rust, loose smut and common root rot. Snowbird and Roblin exhibited similar levels of resistance to tanspot, Septoria tritici, and Septoria nodorum while its reaction to Fusarium head blight was similar to that of AC Barrie. Snowbird has similar grain and flour protein content as other check cultivars but had 1% less protein compared to Roblin. Key words: Triticum aestivum L., Canada Western Hard White, hard white spring wheat, cultivar description, yield, disease resistance
Fusarium populations in roots of oilseed and pulse crops grown in eastern Saskatchewan
Authors: Fernandez Myriam R
Published: April 2011

Roots of canola, flax, lentil and pea crops, commonly grown in rotation with wheat and barley on the Canadian Prairies, were sampled for extent of discolouration and associated fungal populations in eastern Saskatchewan, in 2000 and 2001. Fusarium was the genus most commonly isolated from pulse crops, particularly lentil, and one of the most common genera isolated from oilseed crops. The discolouration severity of pulse and flax roots was associated with Fusarium spp., and that of canola with Alternaria spp. Cochliobolus sativus and other commonly isolated species appeared to be present in roots as weak pathogens or saprophytes. Most of the Fusarium spp. have also been isolated from cereal crops affected by crown/root rot or fusarium head blight (FHB) in the province, although at different relative levels. These included F. avenaceum, the most commonly isolated species, and F. culmorum and F. graminearum, which were among the least prevalent species. This is the first report of isolation of F. graminearum from roots of field-grown pulse and oilseed crops in western Canada. For most crops, the number of tillage operations in the previous 3 yr was positively associated with the occurrence of C. sativus and negatively associated with that of F. avenaceum. Our results suggest that the noncereal crops examined would help to maintain or increase Fusarium inoculum in plant tissue, which might contribute to the development of crown/root rot and FHB in subsequently grown cereal crops, especially under conditions more conducive to disease development. This would especially be the case for pulse crops, which had the highest levels of root discolouration, and F. avenaceum. However, noncereal crops would not be significant reservoirs of inoculum of F. culmorum or F. graminearum. Key words: Fusarium avenaceum, Fusarium graminearum, Fusarium head blight, oilseed, pulse, cereal, tillage, crop rotation
Characterization and comparative analysis of three low molecular weight glutenin C-subunit genes isolated from Aegilops tauschii
Authors: Pei Yu-He , Wang Ai-Li , An Xue-Li , Li Xiao-Hui , Zhang Yan-Zhen , Huang Xiu-Qiang , Yan Yue-Ming
Published: April 2011

Three low molecular weight glutenin subunit (LMW-GS) genes from T121, T128 and T132 accessions of Aegilops tauschii (DD, 2n = 2x = 14) were amplified using allelic-specific PCR primers. The amplified products with a size of about 900 bp were cloned and sequenced. Three complete coding sequences of LMW-GS with 918 bp, 921 bp and 918 bp were obtained and named as LMW-T121, LMW-T128, LMW-T132, respectively. Each gene contained a complete open reading frame and had no introns. The deduced amino acid sequences showed that all belonged to LMW-m type subunit with a predicted molecular weight of about 32 kDa, corresponding to the size of LMW C-subunits. All three subunits possessed eight cysteine residues and had greater homology with previously characterized LMW-m subunits from bread wheat and related species than LMW-s or LMW-i sequences. Some amino acid substitutions and insertion/deletion variations among the sequences were detected. The corresponding three C-subunits in seed endosperm encoded by LMW-T121, LMW-T128, LMW-T132, respectively, were identified and confirmed by SDS-PAGE, MALDI-TOF-MS and direct N-terminal amino acid sequencing. Phylogenetic analysis demonstrated that LMW-m and LMW-s type subunit genes possessed higher identity and they were obviously separated from LMW-i type subunit genes. The LMW-m type might be the primitive form while the LMW-s and LMW-i types are variant forms. Key words: Aegilops tauschii, LMW-GS, AS-PCR, phylogenetic analysis
Effect of divergent selection for root size in field-grown alfalfa
Authors: Chloupek O. , Skácel M. , Ehrenbergerova J.
Published: April 2011

The size of the root system as measured by its electrical capacitance was evaluated on two alfalfa (Medicago sativa L.) cultivars (Zuzana, Palava) for 3 yr. Plants with root system size (RSS) significantly larger or smaller than the cultivar mean were selected and their open-pollinated progenies were evaluated in the following 3 yr. Progenies of plants with large RSS tended to have larger RSS and higher forage yield than progenies of plants with small RSS. The differences for both parameters were significant (P < 0.05) in the case of Zuzana. It is concluded that RSS is a useful selection criterion in alfalfa breeding. Key words: Medicago sativa L., root system size, selection, yield, survival
OAC Paisley oat
Authors: Falk D. E. , Meatherall G. , Reinbergs E.
Published: April 2011

OAC Paisley is a high yielding, lodging resistant, covered oat developed at the Crop Science Department, OAC, University of Guelph. OAC Paisley was selected from the cross of Ogle/OA630-2. It has outyielded the check cultivars over 29 station-years of testing in Ontario, Quebec and the Atlantic Region. OAC Paisley is well adapted to all of Eastern Canada. It has resistance to BYDV and good tolerance to septoria, but is susceptible to crown rust. It should fit well into barley-oat mixtures due to its early maturity and lodging resistance. Key words: Avena sativa L., high yield, lodging resistance, BYDV, septoria
Alpha soybean
Authors: Voldeng H. D. , Anderson J. A. D. , Guillemette R. J. D. , Leonard D. A. , Cober E. R.
Published: April 2011

Alpha is a 2450 crop heat unit soybean (Glycine max [L.] Merr.) cultivar with good yield potential. Key words: Soybean, cultivar description
AC Maridel flue-cured tobacco
Authors: Brandle J. E. , Arsenault W. , Rogers W. D. , Ankersmit J. C. D.
Published: April 2011

AC Maridel is a flue-cured tobacco (Nicotiana tabacum) cultivar bred collaboratively by the Pest Management Research Centre and the Charlottetown Research Centre of Agriculture and Agri-Food Canada. It is a cultivar with high yield, improved leaf quality and is resistant to black root rot (Chalara elegans). It resulted from crosses between two breeding lines originally selected at Delhi (80M11/80K2G). AC Maridel is adapted to the tobacco growing areas of Prince Edward Island. Key words: Nicotiana tabacum, black root rot resistance
Effects of common bean (Phaseolus vulgaris L.) cultivar and rhizobium strain on plant growth, seed yield and nitrogen content
Authors: Buttery B. R. , Park S-J. , Berkum P. van
Published: April 2011

The common bean is generally regarded as a relatively inefficient fixer of nitrogen. Information on the relative importance of host cultivar and rhizobium strain would be useful in guiding a breeding program to improve nitrogen fixation in common bean. Seventeen cultivars of common bean (15 of Meso-American and 2 of Andean origin, differing in nodulation potential, maturity, growth habit and market class) were investigated for symbiotic compatibility with 10 genetically diverse strains of bean rhizobia. In a greenhouse (27/22 °C), five sets of 170 pots were replicated over time: three sets were harvested after 30 d for determination of acetylene reduction activity, plant dry weights, and nitrogen content; two replications were grown to maturity for determination of seed dry weight and nitrogen content. There were highly significant effects of both strain and cultivar on most measured characteristics, but there was no interaction between cultivar and strain. Italian Barlotti produced the greatest plant weight after 30 d, but its final seed yield did not differ significantly from that of the highest yielding cv. BAT271. The strain TAL182 was associated with the greatest plant weight at 30 d, but the final seed yield associated with it was less than that of the most productive strain USDA9001. Strain USDA 2667 was characterized as type I by determination of its 16S rRNA gene nucleotide sequence. The nodules of plants in symbiosis with strains of type IIB had high levels (8.1%) of nitrogen and high levels (227 µmol g−1 h−1) of acetylene reduction activity (ARR). Nodules occupied by strains of type IIA and the type I USDA2667 had intermediate levels of nitrogen (6.9%) and ARR (166 µmol g−1 h−1), while nodules occupied by type 1 strains had low levels of nitrogen (5.2%) and ARR (144 µmol g−1 h−1). Screening of lines, parents and other breeding materials for improved N-fixation may be achieved with any effective strain since no host × strain interaction was detected. Key words: Common bean, Phaseolus vulgaris, nodulation, nitrogen fixation, rhizobium strains, cultivar × strain interaction
Allons low linolenic acid summer rape
Authors: Scarth R. , McVetty P. B. E. , Rimmer S. R.
Published: April 2011

Allons (Brassica napus L.) is a low linolenic acid canola cultivar which produces seed oil with an average linolenic acid content of 2.5%. The low linolenic oil has a shorter hydrogenation time and greater stability than standard canola oil. Allons is higher yielding and contains higher seed oil and lower meal protein than the low linolenic cultivar Stellar. Allons is adapted to the long season B. napus canola growing areas of western Canada. Key words: Rape (summer), low linolenic, cultivar description
The presentation of statistical results in journal articles
Authors: Hall John W.
Published: April 2011

Of the instructions about statistics given to authors, compliance in the Canadian Journal of Soil Science is lowest in providing a measure of variability when reporting quantitative data. The standard error is the most useful of these measures. The coefficient of variation, standard deviation or range is sometimes appropriate alternatives. The least significant difference (LSD) is sometimes used in this role, but authors are then tempted, incorrectly, to omit it when differences are not statistically significant. The LSD can be replaced by the standard error and the rule of thumb that the LSD is approximately three standard errors. Tables of means are easier to read when rows and columns are ordered so the most important variable is in the leftmost column, trends are evident and data relating to comparisons of greatest interest are close together. Tables of correlation coefficients can also be sorted to highlight relationships among the variables. In future, some readers may demand more statistical detail so that statistical methods can be used in literature reviews. Electronic publishing may allow this demand to be met without compromising good communication. Key words: Data presentation, measures of variation, table layout
Temperature and precipitation effects on durum wheat grown in southern Saskatchewan for fifty years
Authors: McCaig T. N.
Published: April 2011

Approximately 60% of Canadian durum wheat (Triticum turgidum L.) is produced in the semi-arid, Brown soil zone of southern Saskatchewan. The Durum Wheat Cooperative Test (DWCT) provides the means of evaluating potential new cultivars, and has been grown at Swift Current, located near the centre of the Brown soil zone in Saskatchewan, for more than 50 yr. Historical yield-related data from the DWCT were analyzed in conjunction with daily precipitation and maximum daily temperature (MaxDT) data with the objective of improving our understanding of the effects of these weather variables on durum wheat grown in this semi-arid region.The highest correlation between the weather variables and grain yield was during the period near the end of June through early July, approximately the time of anthesis. The correlation with kernel number m−2 (KNum) was maximum near the end of June, while the correlation with kernel weight was highest around the third week of July. The maximum effect of these weather factors in limiting yield in the Brown soil zone was through an impact on KNum around anthesis. Hectolitre weight and time-to-maturi-ty appeared to be influenced mainly by the weather in July, while crop height was determined by the weather near the end of June. An analysis which examined cumulative heat-units above threshold MaxDT of 20, 24, 28 and 32 °C indicated that temperatures >24 °C may be detrimental during early June although high temperatures are less common in June than in July. Yield was also negatively impacted by temperatures >20 °C during the first 3 wk of July.Future yield gains in this semi-arid region may be dependent upon the development of cultivars which are more tolerant of drought and high-temperature stress at anthesis. Key words: Triticum turgidum, kernel number, kernel weight, height, maturity, hectolitre weight
Long-term effects of fertilizer on yield and species composition of contrasting pasture swards in the Aspen Parkland of the Northern Great Plains
Authors: Bittman S. , McCartney D. H. , Waddington J. , Horton P. R. , Nuttall W. F.
Published: April 2011

Little is known about the effects of long-term application of fertilizer on the complex pasture swards of the Aspen Parkland region of western Canada. Experiments were conducted, lasting from 1980 to 1992, on five contrasting swards representative of permanent pastures in northeast Saskatchewan to determine the long-term effects of N, P, K and S fertilizer on herbage yield and species composition. The experimental swards consisted primarily of smooth bromegrass (Bromus inermis Leyss.), Kentucky bluegrass (Poa pratensis L), and creeping red fescue (Festuca rubra L.), in varying amounts. Seven fertilizer treatments were applied at each site from 1980 to 1991 (shown as N-P-K-S in kg ha−1): 0-0-0-0, 45-0-0-0, 45-20-0-0, 90-0-0-0, 90-20-0-0, 90-20-50-20, 180-20-0-0. Another treatment (90-20-0-20) was added in 1984. An area within each plot was protected from grazing with wire exclosures and harvested in July and September. Harvested samples were classified according to coarse-leafed grasses (mostly smooth bromegrass), fine-leafed grasses (mostly Kentucky bluegrass and creeping red fescue), legumes and weeds before drying and weighing. Ground cover composition of all plots was measured by a modified line transect technique in 1980, 1987 and 1992. All swards, regardless of species composition, responded positively to fertilizer. The yield increase obtained from applying 45 or 90 kg N ha−1 (0.8 and 0.7 t ha−1, respectively) was more than doubled by adding 20 kg P ha−1 with the N. Nitrogen applied alone did not affect the proportion of bromegrass but increased the proportion of fine grasses in the herbage; adding N and P increased the proportion of coarse grass and at the expense of fine grasses. With respect to sward composition, N decreased the proportion of bromegrass and increased the proportion of bluegrass and fescue whereas adding N and P had the opposite effect. Application of S increased yield 0.9 to 1.8 t ha−1 and greatly increased the proportion of bromegrass in the sward and the harvested herbage of the three sites with low levels of soil S. The residual effect of the N and P treatments on yield was small but the effect on species composition of the herbage was substantial; S produced a residual effect on yield in 1992 and a large residual effect on species composition. The results indicate the need for balanced nutrient application to enhance yield and maintain or improve sward species composition of pastures in the Aspen Parkland. Fertilizer can be used to improve yield on a wide range of sward types. Key words: Bromegrass, Bromus inermis, bluegrass, Poa pratensis, fescue, Festuca rubra, legume, N, P, K, S, grazing, species diversity
AC Foremost red spring wheat
Authors: Thomas J. B. , DePauw R. M. , Knox R. E. , Czarnecki E. , Campbell A. B. , Nielsen J. , McKenzie R. I. H. , Degenhardt K. J. , Morrison R. J.
Published: April 2011

AC Foremost, red-seeded spring wheat (Triticum aestivum L.), combines high grain yield with resistance to prevalent races of common bunt (caused by Tilletia laevis Kuhn in Rabenh. and T. caries (DC.) Tul. & C. Tul.), and loose smut except T9 (caused by Ustilago tritici (Pers.) Rostr. in a semidwarf, photoperiod insensitive background. AC Foremost has improved pre-harvest sprouting tolerance compared with Biggar, AC Taber, and Genesis; improved resistance to leaf rust (caused by Puccinia recondita Roberg ex Desmaz.) and leaf spots (caused by Septoria spp. and Pyrenophora tritici repentis (Died.) Drechs.) compared with Neepawa and Biggar, and earlier maturity compared with Biggar, AC Taber, and Genesis. AC Foremost is eligible for grades of the Canada Prairie Spring (Red) wheat class. Key words: Triticum aestivum L., cultivar description, loose smut resistance, common bunt resistance, high yield, red spring wheat
Seeding date, photoperiod and nitrogen effects on specific leaf area of field-grown wheat
Authors: Hotsonyame G. K. , Hunt L. A.
Published: April 2011

Specific leaf area (SLA), the ratio of leaf area to leaf weight, is an important plant characteristic that affects the rate of dry matter production of crop canopies. It is affected by the conditions of growth of both isolated plants and crop communities, but the extent to which various environmental factors impact on SLA under field conditions is not clearly understood. This study was conducted to study the variability in SLA of leaves on the main culm, and in the leaf canopy as an entity, under different conditions of photoperiod, nitrogen and temperature for a number of wheat genotypes grown under field conditions. Five plantings at approximately bimonthly intervals on 12 May, 5 July and 22 September 1993; and on 9 June and 10 August 1994 were made under both natural photoperiod and an extended photoperiod of 20 h. A split plot design with two levels of nitrogen (0 kg N ha−1 and 150 kg N ha−1) as main plots and four genotypes of wheat comprising two spring types (Norseman and Roblin) and two winter types (Ruby and Harus) as subplots was used.SLA of individual leaves varied among leaf positions, but the pattern of variation was dependent on sowing date and genotype. For May and June sowing dates, SLA increased with leaf number up to leaf 5 and then declined with subsequent leaf numbers for the spring genotypes, but increased to leaf 5 and changed little thereafter for the winter types. For July or August sowing and for both spring and winter genotypes, the change in SLA with leaf position was less clear. The results further showed that some of this variability in SLA with leaf position could be accounted for by the mean air temperatures over which the leaves developed. As temperatures increased from 8 °C to 26 °C, SLA increased to a maximum value achieved at 18–20 °C and then declined. However, there was a large scatter of SLA values around 18–20 °C, due partly to some lower SLA values for the July and August sowing dates. This suggests the impact of other factors such as radiation and the degree of mutual shading within the canopy on SLA. Mean canopy SLA reflected the individual leaf values during the period of leaf production, and varied with sowing date and genotype, although the pattern of genotypic variability was inconsistent over sowing dates; it decreased rapidly after spike emergence presumably reflecting leaf aging. Neither nitrogen nor photoperiod had significant effects on SLA on both individual leaf and canopy bases.The results suggest that temperature is one factor affecting SLA under field conditions, but that further work to identify other factors impacting on SLA in the field will be necessary. For application of simulation models to situations in which temperatures are likely to vary, an accounting for the impact of temperature on the SLA of individual leaves would be desirable. Key words: Specific leaf area (SLA), sowing date, temperature, simulation, wheat
Influence of planting date and environment on Oklahoma wheat grain yield trend from 1963 to 1995
Authors: Epplin F. M. , Peeper T. F.
Published: April 2011

The five-year moving average (5YRMA) wheat (Triticum aestivum L.) grain yield per harvested hectare has declined by more than 18% over the past decade in Oklahoma. By contrast, world wheat yields have increased steadily over the same period. The Oklahoma wheat yield trend during the past decade is inconsistent with expectations. The objective of the research was to determine why the 5YRMA wheat grain yield per harvested hectare did not increase in Oklahoma during the past decade. Five types of potential explanatory variables were investigated: structural change (including government programs), fertilizer use, proportion grazed, planting date and environment. Regression analysis was used to determine that the consequences of improvements in technology, research and education programs, as measured by a linear trend variable, were positive. However, during the past decade, these advancements were overwhelmed by changes in planting date and environmental factors. Key words: Wheat, yield, trend, planting date, environment
Pasture research in the UK: Present knowledge and future prospects
Authors: Davies Alison
Published: April 2011

Pasture research in the UK has increasingly been aimed at understanding the mechanisms that underlie pasture plant responses to different managements. The need to develop agricultural systems that are both sustainable and economically viable has strengthened interest in reliable animal production from pasture and has emphasised the need to understand how white clover can best be maintained in the grazed sward. Breeders are focusing on meeting the nutritional requirements of the grazing animal and are enjoying increasing success in incorporating new genetic material from plant collections into varieties of grass and clover which are better able to withstand environmental stresses. Economic and environmental considerations have stimulated interest in gaining further insights into the nature of (and the reasons for) the species changes which follow reductions in fertiliser inputs and stocking rates. The possibility of harnessing the preferences of different grazing animals to influence vegetational change is being explored. Soil microbiology and nutrient availability in soils (and their influence on future productive capacity) are also influenced by reduced inputs and are subjects attracting increased interest. This paper discusses current understanding of these topics in the UK and identifies some specific problems that require further study. Key words: Clover, grass, grazing, pasture composition, plant breeding
Shearing force of alfalfa stems as affected by seeding rate
Authors: Iwaasa A. D. , Beauchemin K. A. , Acharya S. N. , Bowley S. R. , Buchanan-Smith J. G.
Published: April 2011

Physical properties of forages may provide a simple method of predicting animal voluntary feed intake. Physical measurements, such as shearing force, may indicate the resistance of the forage to particle breakdown during mastication. The objective of this study is to determine the effects of seeding rate on the physical characteristics and cell wall chemical constituents of alfalfa (Medicago sativa L.) stems, and to relate these characteristics to shearing strength. Stems of eight alfalfa cultivars (120, Legend, Multiking 1, OAC Minto, Saranac, Vernal, Vertus, WL320) seeded at 6, 12 and 24 kg ha−1 were harvested in the first and second production years and divided into three 16 cm segments: top, middle and bottom, and the force required to shear each segment was measured using a modified Ottawa Texture Measuring System. For both years, shearing force, segment weight and stem diameter measurements generally decreased as seeding rate increased when measured at the middle and bottom shearing segments on the stem, but this was not observed for the top shearing segment. Effect of seeding rate on differences in segment weight and stem diameter among cultivars was variable among years and stem segments. Concentrations of cell wall constituents in stems were not influenced by seeding rate, and these influenced shearing force to a lesser extent than physical characteristics. Shearing force was directly related to the diameter and weight of the stem. Because of the associations between shearing force and diameter and weight, physical characteristics of the stem may influence forage breakdown during mastication independently, and to a greater extent than cell wall chemical constituents. Key words: Alfalfa, seeding rate, shearing force, cell wall chemical constituents, diameter, weight
Winter-hardiness trials of Vaccinium corymbosum L. in Nova Scotia
Authors: Kloet S. P. Vander , McRae K. B.
Published: April 2011

In order to assess cold tolerance in V. corymbosum L. in Nova Scotia, 336 even-aged seedlings from 21 locations (representing five different habitats and six eastern North American floristic regions) were set out at the Kentville Research Centre in 1978. Frost damage is largely restricted to Coastal Plain plants and to a lesser extent the Appalachian Mountain plants. Principal component analysis indicates that berry weight co-varies negatively with winter-kill and days from the anthesis until fruit ripening. Hardy plants that flower in early May also need the fewest days to produce ripe fruit. Among the 23 early flowering biotypes, six early fruiting biotypes were identified. Key words: Vaccinium corymbosum, highbush blueberries, frost tolerance, drought tolerance, early flowering and fruiting biotypes
Relationship between extract viscosity and kernel size in winter rye
Authors: Gan Y. T. , McLeod J. G. , Scoles G. J. , Campbell G. L.
Published: April 2011

Rye (Secale cereale L.) grain with low extract viscosity (EV) and superior kernel characteristics is desired when used in diets of monogastric animals. Knowledge of the relationship between EV and kernel characteristics is needed to develop an efficient selection strategy for breeding cultivars that meet the two criteria. Grains of 11 open-pollinated population varieties/lines grown in 21 environments were studied to determine the relationship between EV and kernel weight (KWT) among genotypes and environmental effects. Grains of eight out of the eleven varieties/lines were screened into five kernel-size categories, <2.0, 2.0–2.4, 2.4–2.8, 2.8–3.2, >3.2 mm in kernel width, to determine the relationship between EV and kernel width within a genotype. EV was a linear function of KWT; high KWT is indicative of low EV. The degree of the relationship was affected by environment. For example, grains grown at Swift Current had a stronger relationship between EV and KWT than those from Lacombe (b = −1.67 vs. −0.31). For the grain from Swift Current, 60% of variability in EV was attributable to KWT, while for the grain from Lacombe only ≈ 20% of variability in EV was explainable by KWT. Among the various kernel-width categories within a genotype, 60 to 98% of variability in EV was attributable to kernel width, with some genotypes responding to a greater degree than others. In development of winter rye cultivars low in extract viscosity, breeders could combine kernel weight/width into the selection strategy to enhance the selection progress or use kernel weight/width as a reference in selection of extract viscosity trait. Key words: Pentosans, arabinoxylans, kernel weight, Secale cereale
Cattle manure as a nutrient source for barley and oilseed crops in zero and conventional tillage systems
Authors: Stevenson F. C. , Johnston A. M. , Beckie H. J. , Brandt S. A. , Townley-Smith L.
Published: April 2011

Manure application should be equally effective in meeting crop nutrient requirements in zero and conventional tillage systems in order to be sustainable in a semi-arid region. A study was conducted from 1993 to 1996 at Scott and Melfort, Saskatchewan, to determine if feedlot cattle manure and inorganic N fertilizer were equally effective as nutrient sources for barley (Hordeum vulgare L.), canola (Brassica rapa L.) and flax (Linum usitatissumum L.) production, and soil N dynamics, in zero and conventional tillage systems. Inorganic fertilizer was compared with a factorial combination of two manure treatments: manure composition (fresh versus stockpiled), and application rate and frequency (annual versus once every four years). Barley and oilseed yields at Scott did not differ between fertilizer and manure treatments, whether manure was applied annually or once every 4 yr. At Melfort, the site with the highest yield potential, grain yields were 24% lower with manure. This yield reduction could be related to soil N availability; net N mineralization was 37 kg ha−1 lower in plots that received manure rather than inorganic fertilizer. Yield responses to the different types of manure and inorganic fertilizer were similar under zero-till and conventional tillage management. Low levels of N volatilization from the manure, and similar levels of net N mineralization, explained why crop responses to nutrient source did not differ with tillage system. Feedlot cattle manure can be applied as a nutrient source when surface applied in a zero-till system without significant yield reductions compared with soil incorporation in a conventional tillage system. Key words: Cattle manure, tillage, zero-till, barley, canola, flax
OAC Sparta soybean
Authors: Tanner J. W. , Luzzi B. M. , Montminy W. , Gostovic P. , Hume D. J.
Published: April 2011

OAC Sparta is a 3125 CHU soybean (Glycine max [L.] Merr.) cultivar that outyielded check cultivars, had greater plant height and higher seed oil content but less lodging resistance. Key words: Soybean, cultivar description
Energy performance of conservation tillage management for spring wheat production in the Brown soil zone
Authors: Zentner R. P. , McConkey B. G. , Stumborg M. A. , Campbell C. A. , Selles F.
Published: April 2011

There is growing interest in the potential for improving nonrenewable energy use efficiency of traditional agricultural production activities in the Canadian prairies. This study, which was conducted on three soil textures in the Brown soil zone of southwestern Saskatchewan, examined the energy performance of conventional tillage (CT), minimum tillage (MT), and no-tillage (NT) management practices for spring wheat grown in fallow-wheat (F–W) and continuous wheat (Cont W) rotations over a 12-yr period (1982–1993). Metabolizable energy output increased with cropping intensity on a silt loam at Swift Current and on a clay at Stewart Valley (average of 16 751 MJ ha–1 for F–W and 24 110 MJ ha−1 for Cont W), but not on a sandy loam at Cantuar (average 14 828 MJ ha−1) where soil water-holding capacity was limited. Further, because grain yield was rarely significantly influenced by tillage method, the latter had little influence on the overall output of metabolizable energy. Total input of nonrenewable energy per unit of rotation also increased with cropping intensity (average 2585 MJ ha−1 for F–W and 5274 MJ ha−1 for Cont W). This was primarily because of the higher rates of N fertilizer that were required with stubble cropping. We found little or no net energy savings with NT management; the F–W (MT) system tended to have the lowest overall nonrenewable energy requirement at all test sites. Although the use of conservation tillage practices provided significant energy savings in fuel and machinery, particularly for F–W systems, these were largely offset by increases in the energy input for herbicides, and higher rates of N fertilizer that were required for NT managed areas. Consequently, net energy produced (energy output minus energy input) had similar patterns as metabolizable energy output. In contrast, when efficiency was expressed as ratios of energy output to energy input, or quantity of wheat produced per unit of energy input, the values were higher for F–W (average 6.2 and 456 kg GJ−1, respectively) than for Cont W systems (average 3.8 and 278 kg GJ−1, respectively). These measures of energy efficiency also tended to be higher for CT and MT than for NT management on the medium- and fine-textured soils, but on the coarse-textured soil, tillage had no influence on the energy efficiency of the cropping systems. We concluded that the potential for achieving energy savings by adopting conservation tillage management for monoculture wheat rotations is low in this semiarid region. This was because of the lack of consistent yield advantages with MT and NT, and due to the few tillage operations that are traditionally used to control weeds on summerfllow areas and to prepare the seedbed with CT management. Key words: Wheat, minimum tillage, no-tillage, nonrenewable energy, energy output/input, energy efficiency