bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential for winter wheat production in western Canada: A CERES model winterkill risk assessment
Authors: Savdie I. , Whitewood R. , Raddatz R. L. , Fowler D. B.
Published: April 2011

The introduction of a practical winter wheat (Triticum aestivum L.) production system, which utilizes direct no-till seeding into standing stubble immediately after harvest of the previous crop (stubbling-in) and snow trapping, has reduced the risk of winterkill and permitted expansion of the North American crop northeastward to include most of western Canada's agricultural area. The large expanse of this region results in considerable variation in climatic conditions and associated risks of winterkill. In the present study, 29 yr of climatic data for 53 stations were analyzed utilizing the CERES winterkill algorithm with the objective of determining the spatial distribution of various winterkill levels for stubbled-in "Norstar" winter wheat in western Canada. These simulations indicated that insulating snow cover is the pivotal climatic factor in winter wheat survival in the arid and transitional grassland ecoregions. The reliability of early winter snow cover appears to be more critical than the total overwinter amount. In the more northerly boreal climatic ecoregion, the limiting factor may be poor acclimation conditions and/or early incursion of killing Arctic air. This study demonstrates the usefulness of crop models, such as CERES, in extending the results of site-specific field studies to new areas and in risk analysis for planning and decision making. Key words: Winter wheat, winterkill, CERES model, Western Canada
The interactive effects of increased evaporative demand and soil water on photosynthesis in maize
Authors: Berard R. G. , Thurtell G. W.
Published: April 2011

A field-portable whole-plant enclosure system was used to study the effect of increased evaporative demand on photosynthetic rates of maize (Zea mays L.) subjected to various root medium treatments. The system consisted of two transparent chambers, each capable of maintaining a fully grown maize plant at ambient conditions while enabling different evaporative demand treatments by controlling the humidity. The rooting media consisted of silt loam soil held at three levels of soil moisture content covering a wide range of available moisture, and a hydroponic medium consisting of 25-L pails containing "Turface" and supplied three times daily with a nutrient solution. Measurements were carried out during the post-silking period from 22 July to 6 Sept. 1987 and consisted of at least 4 d of continuous monitoring of photosynthesis and transpiration rates from early morning till sundown. The effect of increased evaporative demand on photo-synthetic rates was relatively small, with average photosynthetic reductions of approximately 4–6% in all root medium treatments. Soil moisture content did not have any effect on the reduction of photosynthesis which occurred at high evaporative demand. However, absolute photosynthetic rates were significantly reduced by low soil moisture. It is suggested that atmospheric conditions leading to high transpiration rates are much less important than soil moisture conditions in causing yield reductions due to reduced photosynthetic rates. The results support recent evidence by other workers that soil water status can influence stomatal conductance and photosynthesis without the intermediary influence of leaf water status. Key words: Photosynthesis, transpiration, maize, soil water content, VPD, leaf conductance
A damage index for estimating yield loss in sunflowers caused by sunflower midge
Authors: Bracken G. R.
Published: April 2011

A description of six categories of damage to sunflower heads by sunflower midge, Contarinia schultzi Gagne, is presented based on visual estimates of the relative area of seed destroyed as well as the degree of head cupping expressed as the ratio of the length of the thickened receptacle to the head diameter. Fractional yields of the six damage classes (0–5), determined from heads collected in commercial fields, were 1.0, 0.82, 0.69, 0.41, 0.15 and 0. Head diameter was significantly associated with midge damage and accounted for more variation than the damage rating in regressions of the two factors on yield. Ratings by observers with varying degrees of experience using the damage descriptions agreed significantly in evaluating the same group of heads. The sunflower midge index provides a simple and standard method for comparing varietal reactions to midge and for estimating commercial losses. Key words: Sunflower, Contarinia schultzi Gagne
Effect of N and P fertilizer on establishment of alfalfa with a wheat companion crop
Authors: Bittman S. , Waddington J. , Pulkinen D. A.
Published: April 2011

This study examines the effect of fertilizer applied before seeding on the grain yield of a wheat (Triticum aestivum L.) companion crop and on the forage yield and crude protein content of the underseeded alfalfa (Medicago media Pers.) in subsequent years. The crops were seeded into stubble at five sites in northeast Saskatchewan on soils ranging in texture from silty loam to silty clay. Combinations of three N rates (0, 57 and 114 kg ha−1) and three P rates (0, 28.5, 57 kg ha−1) were applied before seeding to the companion crop plots. Alfalfa was also seeded alone (clear-seeded) at the three P rates. Application of N increased wheat yield but lowered yield of companion-seeded alfalfa to a range of 65–95% of clear-seeded alfalfa in the year after seeding, depending on wheat yield. Alfalfa yields in subsequent years were more variable where wheat yields were high than where wheat yields were low. The wheat crop yielded 1300–2600 kg ha−1 of grain but reduced alfalfa yield over three years by 400–2100 kg ha−1. Phophorus increased yield of wheat without decreasing accumulated yield of alfalfa over 3 yr. The results of this study support the practice in northeast Saskatchewan of supplying N to the requirement of wheat and P to the greater requirement of alfalfa if these crops are seeded together. Key words: Forage, underseeding, yield, protein, Medicago media Pers., Triticum aestivum L.
Altai wild ryegrass yield response to herbicides applied during establishment
Authors: Malik N.
Published: April 2011

The effects on productivity of Altai wild ryegrass (Leymus angustus (Trin.) Pilger) of 14 herbicide treatments applied during establishment were investigated in two field experiments at Melfort, Saskatchewan. Weed control achieved with metsulfuron, chlorsulfuron, thifensulfuron and tank-mixed applications of bromoxynil with diclofop or fenoxaprop during the establishment year ensured satisfactory forage establishment which in turn caused a "residual effect" for 1–3 yr increasing individual cut as well as cummulative forage dry matter yields significantly. When established with a heavy broadleaf weed infestation (138 m−2) dominated by stinkweed (Thlaspi arvense L.) in 1985, bromoxynil plus diclofop increased yield 359% over a 3-yr period. Sulfonylurea herbicides increased yield 221–346%. Bentazon and MCPA/mecoprop/dicamba increased yields 85%. With a moderate weed infestation (40 m−2) dominated by lamb's-quarters (Chenopodium album L.) in 1986, sulfonylurea herbicides and bromoxynil plus the graminicides increased cummulative yields only 37–59%. Sethoxydim and fenoxaprop, tested alone, caused significant crop injury in both experiments. Key words: Altai wild ryegrass, Leymus angustus (Trin.) Pilger, herbicide, weed control, forage yield
Germination and growth of Solanum ptycanthum and Solanum sarrachoides
Authors: Hermanutz L. A. , Weaver S. E.
Published: April 2011

The distribution and abundance of hairy nightshade (Solanum sarrachoides Sendt.) has been increasing relative to that of eastern black nightshade (Solanum ptycanthum Dun.) in cultivated fields in southern Ontario. The germination and early growth of the two species were compared under controlled environmental conditions. Individual seeds of hairy nightshade weigh almost twice as much as those of eastern black nightshade. Time to 50% germination of seeds of hairy nightshade was faster over a range of temperatures, and total germination in the dark and at low temperature was greater compared to seeds of eastern black nightshade. Seedlings of hairy nightshade also grew faster than those of eastern black nightshade, having greater height, leaf number, and aboveground dry weight at 10 and 21 d after emergence in growth chambers at 28/20 and 22/14 °C. Individuals of hairy nightshade began to reproduce earlier with a consequent decrease in vegetative growth. By 35 d after emergence, leaf area and aboveground dry weight of seedlings of eastern black nightshade equalled or exceeded those of hairy nightshade. Differences between species were consistent for populations from two separate locations in Ontario. Key words: Germination, eastern black nightshade, hairy nightshade
Morrison barley
Authors: Ho K. M.
Published: April 2011

Morrison is a two-rowed spring feed barley (Hordeum vulgare L.) cultivar developed by the Plant Research Centre, Agriculture Canada, Ottawa. It was selected from a Rodeo/Gitane cross. Morrison has high yield, high test weight, large kernels, good lodging resistance and a high degree of resistance to powdery mildew (Erysiphe graminis D.C.). It is suitable for growing in Eastern Canada. Key words: Hordeum vulgare L., two-rowed barley, feed barley, high yield
Topper field pea
Authors: Ali-Khan S. T.
Published: April 2011

Topper, a yellow-seeded field pea cultivar with high-yielding ability, large seed size and early maturity was released in Canada in 1989. Topper is well adapted to western Canadian growing conditions where it has produced higher yield than check cultivars Century, Express, and Titan in registration tests conducted from 1985 to 1988. Key words: Pea, field pea, dry pea, cultivar description
Selecting for earliness and yield in sorghum at different sites
Authors: Plett S. , Nelson L. A. , Clegg M. D.
Published: April 2011

Feasibility of selection of sorghum [Sorghum bicolor (L.) Moench] lines in a long–season environment for early maturity and yield was studied. Fifty-seven male lines from three different origins and F1 progenies produced by crossing the lines to three early-maturing female lines were used for these evaluations. Lines selected for yield had highest yield in a long-season environment but showed no yield advantage in short-season areas. There were lines from all three origins which should be useful in the locations tested. Selection for earliness and yield appeared feasible in a long season area. Key words: Heritability, correlation
OAC Kippen spring barley
Authors: Falk D. E. , Reinbergs E.
Published: April 2011

OAC Kippen is a high-yielding six-rowed spring barley that is particularly well adapted to the spring cereal growing area of southwestern Ontario. It is a medium-height, mid-season barley with good straw strength and mid-sized, plump, uniform kernels with a high hectoliter weight. OAC Kippen has good resistance to powdery mildew and some resistance to most other diseases of barley in eastern Canada. Key words: Barley, Hordeum vulgare, powdery mildew resistance, cultivar description
The association between potato tuber yield and the components of yield in irrigated and dryland environments in the prairies
Authors: Lynch D. R. , Kozub G. C.
Published: April 2011

A study of the yield structure of nine potato genotypes was carried out over a 3-yr period in irrigated and dryland environments in the Prairies. This was undertaken to develop an understanding of yield component interactions, which could be useful in the selection for yield in early clonal generations of the Prairie Potato Breeding Project. Path coefficient analysis was used to partition correlation coefficients among yield and yield components into direct and indirect effects. Marketable yield of tubers in the irrigated and dryland environments differed markedly as did interactions between components in determining yield. Mainstem and tuber number were associated positively with yield under irrigated but not under dryland conditions. Tuber yield was strongly associated with average tuber weight under both irrigated and dryland conditions. The study indicates that consideration of yield component interactions in early generation selection "activities" could assist in the identification of high-yielding genotypes. Key words: Path coefficient analysis, Solanum tuberosum, selection, early clonal generations
Influence of wear-stress on turfgrass growth components and visual density ratings
Authors: Cattani D. J. , Clark K. W.
Published: April 2011

This study compared the relationship between visual density ratings and various turfgrass growth components using the combined data of 10 creeping bentgrass clones exposed to or not exposed to simulated foot-type wear-stress. Measurements were determined on 28 June, 12 July, and 2 Aug. 1985. There was a trend towards a reduction, rarely significant, in all turfgrass growth components measured due to simulated wear. Significant reductions in the visual density ratings occurred for the 12 July and 2 Aug. rating dates. There was no difference in the relationship between visual density ratings and the turfgrass growth components due to applied wear-stress. Visual density ratings were correlated to tiller number and leaf number and inversely to dry weight/tiller. Tiller number and leaf number are linearly related. Key words: Agrostis stolonifera, creeping bentgrass, visual density rating, tiller number, leaf number, simulated wear
Leaf appearance rate of summer rape
Authors: Morrison M. J. , McVetty P. B. E.
Published: April 2011

Leaf appearance rate (LAR) is defined as the slope of the regression of leaf number on time of appearance. LARs were calculated for summer rape using both calendar days (CD) and growing degree days (GDD) as measurements of time. The relationship between the number of leaves and GDD or CD was linear. LARs after emergence were 0.022 leaves GDD−1 or 0.247 leaves d−1. Summer rape was grown in growth cabinets set at different mean temperatures to study the effect of air temperature on LAR. The relationship between leaf number and time was linear. When CD were used as a measure of time, LAR increased as mean temperature increased, while the reverse was true when GDD were used to measure time. Cabinet and field LARs were compared at a field mean temperature of 16.5 °C. Cabinet LARs were 0.021 leaves GDD−1 or 0.22 leaves CD−1 which were similar to those calculated in the field. The linear regression equation describing the relationship between LAR (leaves GDD−1) and mean cabinet temperature was used with field-measured daily mean temperatures and GDD to predict the number of leaves for field conditions. When observed number of leaves were plotted against predicted number of leaves, the resulting slope was not significantly different from one, indicating that the model developed in the growth cabinet can be used to predict LAR in the field. Key words: Leaf appearance rate, Brassica napus, phyllochron
Reaction of spring barley to common root rot under several moisture regimes: Effect on yield components, plant stand, and disease severity
Authors: Grey W. E. , Engel R. E. , Mathre D. E.
Published: April 2011

The reaction of spring barley to common root rot and its effect on yield components, plant stand, and disease severity was studied under several moisture regimes. Infection of barley from natural soil inoculum, primarily Cochliobolus sativus, was augmented with inoculum of C. sativus or Fusarium culmorum to insure uniform disease pressure during plant development. In one study during the 1986 and 1987 growing seasons, a line-source sprinkler irrigation system was utilized to establish a soil moisture gradient from a high-moisture regime receiving both irrigation water and rainfall to a dryland regime receiving only rainfall. In 1986, a second study was carried out to examine the effect of soil moisture at three locations that differed in annual precipitation. Plant emergence and harvestable tillers were reduced by C. sativus in both studies as compared to the noninoculated controls. Grain yield loss was associated with C. sativus and low plant density under drought but not under moderate to high moisture conditions. In the irrigated moisture regimes, moderate and high rainfall locations, the inoculated plants compensated for reduced plant stand and harvestable tillers by producing heavier kernels. Disease severity, based on the subcrown internode lesion development during the soft dough growth stage, did not differ in the dryland and irrigated moisture regimes. However, disease severity was higher in the drought location than in the moderate and high rainfall locations. Prolonged drought and disease pressure during seedling development can result in grain yield reductions, whereas subsequent moisture will affect the crop's ability to compensate for common root rot. Key words: Hordeum vulgare, ranking and selection, canopy temperature
Wild mustard interference in traditional and semi-leafless field peas
Authors: Wall D. A. , Friesen G. H. , Bhati T. K.
Published: April 2011

Field studies were conducted in 1987, 1988 and 1989 to determine the competitive effect of wild mustard (Sinapis arvensis L.) on two field pea (Pisum sativum L.) cultivars; Century, a traditional cultivar, and Tipu, a semi-leafless cultivar, each planted at recommended (172 kg ha−1) and half the recommended seeding rate (86 kg ha−1). For both cultivars, 20 wild mustard plants m−2 reduced seed yields from 2 to 35% at the recommended seeding rate and from 4 to 35% at the low seeding rate. Tipu was more competitive with wild mustard when planted at the recommended seeding rate than when planted at half the recommended rates. Seeding rate had only a moderate effect on wild mustard competition in Century in years with normal precipitation. For both cultivars the effect of wild mustard interference on yield was influenced by the amount of precipitation received, with the greatest yield losses occurring in seasons with normal to high rainfall. Key words: Field peas, competition, weed density, seeding rate, cultivars, yield, rectangular hyperbola
Effect of plant density and herbicide application on alfalfa seed and weed yields
Authors: Moyer J. R. , Richards R. W. , Schaalje G. B.
Published: April 2011

Alfalfa was seeded in row spacings of 36, 72 and 108 cm and at broadcast seeding rates of 0.33, 1.0 and 3.0 kg ha−1 on irrigated land at Tilley (1983) and Lethbridge (1984), Alberta to determine the effect of plant density on weed growth and alfalfa seed yield. During the seed-producing years at each location, herbicide treatments were overlaid on seeding treatments in a split-block arrangement to assess the joint effect of herbicides and plant density on alfalfa seed yield. Hexazinone was the main herbicide used for weed control. Alfalfa seed and weeds were harvested for 5 yr following alfalfa establishment. Alfalfa seed yields tended to be maximum with 36-cm row spacings or the 3.0 kg ha−1 broadcast seeding rate, and were similar in row-seeded and broadcast-seeded alfalfa. Dry matter yields of weeds decreased as row spacings decreased or the broadcast seeding rate increased. Hexazinone controlled quackgrass, sow thistle, flixweed and kochia. In the experiment at Tilley with perennial weed infestations, mean alfalfa seed yields from 1984 to 1985 were 20% larger when herbicides were used than in the untreated check. Alfalfa plant densities slightly larger than currently recommended usually produced the largest seed yields and smallest weed infestations. Key words: Medicago sativa, quackgrass, kochia, sow thistle, flixweed, hexazinone
OAC Dorado soybean
Authors: Beversdorf W. D. , Hume D. J. , Gostovic P. , Muscat J. C. , Pararajasingham S.
Published: April 2011

OAC Dorado is a soybean (Glycine max (L.) Merr.) cultivar which is 1 d earlier in maturity than Hodgson and 9% higher in yield in Ontario trials. Key words: Soybean, cultivar description
Eejay, Altai wild ryegrass
Authors: Lawrence T. , Jefferson P. G. , Ratzlaff C. D.
Published: April 2011

Eejay Altai wild ryegrass, Leymus angustus (Trin.) Pilger, exhibits 18% greater seed yield and the same forage yield compared to Prairieland. Compared to Pearl Altai wild ryegrass, it yields less (91%) seed but more forage (114%). It is distinct from Prairieland or Pearl because 75% of the plants are nonglaucous. Key words: Leymus angustus (Trin.) Pilger, cultivar description, wild ryegrass (Altai), seed yield, forage yield
Control of volunteer alsike clover in timothy grown for seed
Authors: Darwent A. L. , Smith J. H. , Lefkovitch L. P.
Published: April 2011

A study was conducted in 1-yr-old stands of timothy (Phleum pratense L.) to evaluate spring applications of several herbicide treatments for the control of volunteer alsike clover (Trifolium hybridum L.). In one 3-yr experiment, clopyralid at 0.2 kg a.i. ha−1, alone or with 2,4-D at 0.4 kg acid equivalent ha−1 effectively controlled alsike clover (flower production and the dry weight of aboveground parts were reduced by nearly 100% and 96% or more, respectively). Clopyralid at 0.1 kg ha−1, alone or with 2,4-D at 0.4 kg ha−1, and picloram/2,4-D (1:16) at 0.4 kg ha−1 provided similar control in 2 of 3 yr. In the other year, the clopyralid alone (0.1 kg ha−1) and picloram/2,4-D treatments reduced alsike clover flower production by 75% or more but the dry weight of aboveground parts was reduced by less than 55%. 2,4-D alone had little effect in reducing either the flower production or dry weight of aboveground parts of alsike clover. Seed yields of timothy were increased by herbicide treatments which provided effective control of alsike clover when vegetative growth of the latter species was vigorous. In another 3-yr experiment conducted in weedfree stands of 1-yr-old timothy, none of the above treatments had any effect on the seed yield, weight per 100 seeds or seed germination of the crop. Key words: Volunteer alsike clover, timothy, seed yield, seed quality, crop tolerance
Mentha arvensis control with amino triazole and glyphosate
Authors: Ivany J. A.
Published: April 2011

Field experiments showed that field mint (Mentha arvensis L.) could be controlled by using amino triazole or glyphosate applied where a crop was not present. Both herbicides gave comparable control with application at the six-leaf stage but, at the flowering stage, glyphosate was more effective than amino triazole, based on visual control rating in the year of application. Counts of regrowth shoots per square meter the next summer showed both herbicides to be equally effective in controlling field mint. Application at the flowering stage was more effective than at the six-leaf stage in one of the 2 yr of the study. Key words: Mentha arvensis, amino triazole, glyphosate, application stage, field mint
Effets de l'éclairage d'appoint sur la croissance et la productivité du poivron cultivé en serre
Authors: Deniers Dominique André , Charbonneau Josée , Gosselin André
Published: April 2011

The young plants of three cultivars of green pepper were subjected to four lighting systems: (1) natural lighting, (2) 75 μmol m−2 s−1 of supplementary lighting (HPS lamps) for a photoperiod of 16 h, (3) 125 μmol m−2 s−1 of supplementary lighting for 16 h, and (4) 125 μmol m−2 s−1 of supplementary lighting for 20 h. Two growing media were also compared, rockwool and a peat moss medium. The use of supplementary artificial lighting substantially increased the specific weight before and after drying, the percentage of dry matter, early, commercial and total yields, the total number of fruits harvested and the average weight of commercial fruits. Compared to the 75 μmol m−2 s−1 treatment, the two 125 μmol m−2 s−1 treatments resulted in increases in all parameters studied. The use of supplementary lighting of 125 μmol m−2 s−1 for 20 h, compared with 16 h, significantly increased only the productivity of the young plants and the total number of fruits harvested. The young plants subjected to supplementary lighting treatments were 1–2 wk earlier than the young plants which received natural lighting only. The peat moss medium resulted in an increase in the specific weights before and after drying, but no significant difference was observed in the productivity of the young plants. In general, the Evident cultivar was the most productive, followed by Duplo and Delphin. Key words: Sweet pepper, Capsicum annuum L., supplementary lighting, HPS, growing media
Breeding for root yield in alfalfa
Authors: Saindon G. , Michaud R. , St-Pierre C. A.
Published: April 2011

Winter survival of alfalfa (Medicago sauva L.) has often been associated with the size of the root system but breeding for a larger root system has never received much attention. The objectives of this study were to detect variability for root traits among seven alfalfa entries grown under two nitrogen fertilizer treatments (R- and N-treatments) which consisted of Rhizobium nitrogen fixation and inorganic nitrogen fertilizers, respectively; to select for root yield in two alfalfa cultivars grown under the same two treatments and to measure resulting progress; and to determine which of the two N regimes is more appropriate for root yield selection. Variability for root yield, number of laterals, crown width and top yield was found among R-treated entries whereas only the crown width varied among the N-treated ones. The evaluation under both treatments showed that one cycle of bidirectional phenotypic selection made under both the R- and N-treatments was sufficient to allow the formation of divergent populations for root yield with the exception of Apica-derived populations which showed inconsistent or no responses when evaluated under the N-treatment. Independently of the cultivars and treatments used for selection and evaluation, asymmetries of response were observed. Possible explanations are proposed but additional cycles of selection are needed to provide definitive conclusions. Indirect selection responses observed for top yield, crown width, and root branching should make selection for increasing root yield in alfalfa attractive. Key words: Medicago sativa L., root branching, realized heritability, asymmetry of response, indirect response
Relationship between spring vigor and the presence of adventitious roots in established stands of red clover (Trifolium pratense L.)
Authors: Montpetit J. M. , Coulman B. E.
Published: April 2011

Two experiments were undertaken to investigate the relationship between the presence of adventitious roots growing from the crown of red clover plants and the spring vigor of those plants. Experiment 1 was conducted in the springs of 1988 and 1989 in commercial stands of red clover-timothy mixtures entering their third year. Two hundred and thirty-seven plants were visually rated for spring vigor and degree of adventitious rooting using an ordinal scale. Experiment 2 was carried out on a research plot entering its fourth year and consisting of mixtures of red clover and timothy. Visual scores, taproot and adventitious root volumes and foliage weight were recorded. In all experiments significant differences (P < 0.01) in average spring vigor score were found among the five root classes. Correlation coefficients between spring vigor and adventitious root scores were 0.49, 0.65 and 0.58 for exp. 1 (springs of 1988 and 1989) and exp. 2, respectively. Adventitious root volume made up 86% of total root volume in exp. 2. Significant positive linear relationships were found between foliage weight and adventitious root and taproot volumes. It was concluded that profuse production of adventitious roots imparts better spring vigor to red clover. Key words: Taproot, adventitious root, red clover
Effect of imazamethabenz on green foxtail, tartary buckwheat and wild oat at different growth stages
Authors: Harker K. N. , O'Sullivan P. A.
Published: April 2011

Field experiments were conducted at the Lacombe Research Station to determine the influence of growth stage on the control of wild oat (Avena fatua L.) and Tartary buckwheat (Fagopyrum tartaricum (L.) Gaertn.) with imazamethabenz in wheat (Triticum aestivum L.). In greenhouse experiments, the effct of imazamethabenz on canola (Brassica campestris L.) or green foxtail (Setaria viridis L. Beauv.) at two growth stages was also studied. Canola and wild oat were highly susceptible, Tartary buckwheat was somewhat less susceptible, and green foxtail was rather tolerant to imazamethabenz. Imazamethabenz was much more effective on early growth stages of wild oat (2 leaf) and Tartary buckwheat (1–2 leaf), whereas the control of canola and the suppression of green foxtail was much less dependent on growth stage. Linear regression equations were developed to describe the response of the above species to the imazamethabenz treatments. Key words: AC 222, 293; phenology; regression; Setaria viridis; Fagopyrum tartaricum; Avena fatua
Effects of summer and winter annual scentless chamomile (Matricaria perforata Mérat) interference on spring wheat yield
Authors: Douglas D. W. , Thomas A. G. , Peschken D. P. , Bowes G. G. , Derksen D. A.
Published: April 2011

The influence of summer and winter annual scentless chamomile (Matricaria perforata Mérat) on the yield of spring wheat in Saskatchewan was determined. In experimental plots, spring wheat was seeded into barley stubble where summer and winter annual scentless chamomile had been established. A rectangular hyperbolic model was used to describe the relationship between wheat yield and the density of flowering scentless chamomile plants. Winter annuals caused more yield reduction than did summer annuals. Weather conditions appeared to have an influence on the effect of scentless chamomile on spring wheat yield. The same model was fitted to sample data from farmers' fields and showed yield losses similar to those on the experimental plots. The rectangular hyperbolic model fitted the data best when high weed densities occurred. At densities more typical of those found in farm fields, the asymptotic yield loss parameter of the model was poorly estimated. Key words: Scentless chamomile, Matricaria perforata, yield loss, weed competition, rectangular hyperbola, spring wheat
NattoKing K87 soybean
Authors: Bradner N. R. , Simpson R. D. , Hadlock A. A.
Published: April 2011

NattoKing K87, a Maturity Group I soybean (Glycine max (L.) Merr.) cultivar, yields more, has smaller seeds, lodges less and matures later than Canatto. Key words: Glycine max, NattoKing K87 cultivar, cultivar description, soybean
Hero summer rape
Authors: Scarth R. , McVetty P. B. E. , Rimmer S. R. , Stefansson B. R.
Published: April 2011

Hero summer rape (Brassica napus L.) is a cultivar with high concentrations of erucic acid in its seed oil and low levels of glucosinolates in the oil-free seed meal. The oil provides a good source of erucic acid for many industrial applications and the meal can be used in the feed industry. The higher erucic acid content of Hero over Reston is of considerable economic importance in the industrial oil market. Hero is adapted to the B. napus growing areas of western Canada. Key words: Rape (summer), high erucic acid-low glucosinolate, cultivar description
Irrigation of greenhouse tomatoes grown in "Harrow" peat-bags
Authors: Papadopoulos Athanasios P. , Tan Chin S.
Published: April 2011

Three spring and two fall crops of greenhouse tomato (Lycopersicon esculentum L. Mill; various cultivars) grown in "Harrow" peat bags were irrigated 1, 4, 8 or 16 times daily. All plants received the same volume of fertilizer solution which varied with time from 0.2 to 1.0 L plant−1 d−1 according to crop and environmental conditions. The results showed little or no effect of irrigation frequency on early or total yield, number of grade no. 1 fruit, or fruit size. Key words: Lycopersicon esculentum, marketable yield
Sorghum isoprenoid pathway responses to manganese concentration
Authors: Wilkinson R. E.
Published: April 2011

The influence of manganese concentration (0.1−20 μM) on the incorporation of [14C] isopentenyl pyrophosphate (IPP) into gibberellin precursors by cell-free extracts from etiolated coleoptiles was investigated in sorghum [Sorghum bicolor (L.) Moench] cultivars ranging in acid-soil stress sensitivity. Mn2+ concentration influenced 14C-IPP incorporation in the acid-soil-sensitive cultivars (Funk G522DR, TAM428, and SC599) but not in acid-soil-stress-tolerant cultivars (SC574, SC283). Mn2+ concentration influenced the conversion of geraniol (G) to farnesol (F) in three cultivars (TAM428, SC283, and SC574). SC574 also exhibited an influence of Mn2+ concentration of F conversion to geranylgeraniol (GG). Mn2+ concentration did not influence the conversion of G to GG in Funk G522DR and F was the major accumulation product. Isoprenoid pathway conversions were not influenced by Mn2+ concentration in SC599 but G accumulated. Thus, there is considerable genetic diversity in the isoprenoid pathway biosynthetic reactions to Mn2+ within a single crop species and changes occur in the production of biosynthetic units as the physiological environment is altered. Acid-soil stress is a multifactored physiological problem to the plant. Explanation of physiological responses to "stress" requires evaluation of individual factors and integration of the whole ecosystem influence on plant growth. Key words: Isoprenoid biosynthesis, manganese concentration, geranyl pyrophosphate, farnesyl pyrophosphate, geranylgeranyl pyrophosphate, acid-soil stress
Ethephon effects on barley in central Alberta
Authors: Taylor J. S. , Foster K. R. , Caldwell C. D.
Published: April 2011

Ethephon, a plant growth regulator used to prevent lodging in cereals, was tested on barley (Hordeum vulgare L.) cultivars representing a cross-section of types grown in Alberta, Canada over a period of 5 yr. The study was conducted in two parts: in the first part (1983–1985), ethephon at 0.48 kg ha−1 was applied at Zadoks growth stage 45 to four cultivars growing under natural-rainfall conditions. In the second part (1986–1987), a more extensive variety test was conducted (12 cultivars), natural rainfall was supplemented with irrigation when necessary, and ethephon was applied at 0.28 kg ha−1 at Zadoks 45. The effect of ethephon on height, lodging, tillering, days to maturity, grain and straw yield, harvest index, 1000-grain weight, and seeds spike−1 was analysed. Ethephon reduced height in all of the cultivars. Where lodging occurred, it was reduced by ethephon treatment. During the first 3 yr under relatively dry conditions, grain yield was reduced and straw yield increased in 2 out of the 3 yr. In the second part of the study, in which moisture levels were non-limiting during the growing season, ethephon increased yield in 1 yr due to an increase in productive tillers. The yield component consistently affected by ethephon was the number of seeds spike−1. In the 4 yr that this component was examined, a significant decrease in seeds per spike was noted following ethephon treatment. Under conditions of natural rainfall, ethephon effects on days to maturity (Zadoks 91) were variable; under irrigated conditions, ethephon increased the number of days required for the barley to reach maturity by 2 d. Differences among the various cultivars in their response to ethephon are discussed. Key words: Barley, Hordeum vulgare L., cultivars, ethephon, lodging, grain yield, tillering
Effet des types de sol sur la production de semence du trèfle rouge
Authors: Belzile Lucius
Published: April 2011

Red clover (Trifolium pratense L.) was grown for seed production after the seeding year on two different types of soils, in the same climatic area. An important difference in yield which was often related to cultivar and sometimes to year was observed between the two soils — the light soil, Saint-André gravelly loam, produced more seed than the heavy Kamouraska clay. Seed yield differed between cultivars with Florex and Arlington producing the most. On an annual basis, the thousand-grain weight was higher on Kamouraska than on Saint-André. The percent germination was not influenced by soil type and cultivar but variation between years was observed. The production of heads per plant was higher on Saint-André. The number of seeds produced per plant and per head was, as for yield, higher on Saint-André than Kamouraska. The influence of cultivars and years was not always visible on these last parameters. Therefore these results demonstrate that generally the success of red clover seed production depends not only on cultivar and climatic conditions, but that within the same climatic area the type of soil is a major factor. Key words: Red clover, seed production, soil effect, year of harvest, cultivar, yield components
Effect of rate of nitrogen fertilizer on the above- and below-ground biomass of irrigated bromegrass in southwest Saskatchewan
Authors: Leyshon A. J.
Published: April 2011

A 9-yr study was conducted on an alluvial clay loam at Swift Current, Saskatchewan to determine the effect of annual applications of urea-N (46-0-0) fertilizer on production, nutrient quality, N use efficiency, root mass, and root distribution of bromegrass (Bromus inermis Leyss.). Nitrogen was applied annually at the rates of 0, 50, 100, and 200 kg ha−1 N to an established stand of bromegrass. Plots were flood irrigated. Forage DM yields increased linearly with rate of N applied. In all years, the slope of the response was similar and averaged 24 kg DM kg−1 N. The average y-intercept value was 1794 kg DM ha−1. In years 1–4, the N concentration in the grass was depressed at low N rates but after 5 yr the N concentration increased at all N rates. Tissue [Formula: see text] levels over 100 ppm occurred at the 200 kg N rate after 3 yr. Applications of N reduced plant P in all years; the extent depended on N rate. Uptake of N increased with increasing N rate as did the apparent N recovery. Nitrogen rate had no effect on root mass or distribution. Root mass totalled 13 888 kg DM ha−1 to 105-cm depth. Approximately 36% of the root mass was in the top 7.5 cm, 11.9% in the 7.5- to 15-cm depth and 16.9% in the 15-to 30-cm depth. Estimates of the soil space occupied by roots indicate that they would occupy a large proportion of the available pore volume. It was concluded that producers growing bromegrass under irrigation on medium- to heavy-textured soils in southern Saskatchewan can consistently expect considerable increases in hay yield of good quality with N fertilizer at rates up to 200 kg N ha−1. While forage production increased linearly in response to N fertilization, root accumulation remained at a constant level. Further studies are needed to establish maximum yields and economic rates of N application. Key words: N rate, N recovery, roots, forage N, forage P
Weed community structure in spring-seeded crops in Manitoba
Authors: Thomas A. G. , Dale M. R. T.
Published: April 2011

The phytosociological structure of weed communities in spring wheat, barley, oats, flax, and canola was investigated using data collected during a 3-yr survey of 1384 fields in Manitoba. Fields were surveyed during July and August, after the application of all herbicides. Association and cluster analysis techniques, using the presence or absence of species in a field, were employed to distinguish co-occurring groups of species. Only a small number of significant positive and negative associations were found between species and only minor clusters with a few species were formed at low similarity levels. These results indicated that the weed community was composed of species responding to conditions more or less independently of each other. A comparison of weed associations among the five crops and four geographic regions in the province indicated that the weed community structure was determined largely by climatic variables. The pattern of weed association in the four geographic regions was correlated with differences in temperature and precipitation during the spring and summer. The lack of floristic differentiation was attributed to the fact that production practices were similar for the five spring-seeded crops. Key words: Weed communities, weed ecology, cluster analysis, association analysis
Preseeding tillage and postseeding packing effects on spring wheat growth in a semiarid environment
Authors: Foster R. K.
Published: April 2011

Using a pneumatic seeding implement, field studies were established to determine the effect of preseeding tillage and postseeding packing on spring wheat emergence, growth, grain yield and maturity. The first year of this study (1981) was drier and warmer than the 30-yr mean. The second year (1982) was wetter and temperatures were lower. During 1981, preseeding tillage increased plant emergence by 24% (98 vs. 122 plants m−2), while no effect was observed in 1982. Preseeding tillage increased grain yield by 8 and 4% over the same periods. Postseeding packing increased plant emergence by 19% in 1981 and 7% in 1982. Increased grain yield due to packing was 10% in 1981 and 7% in 1982. A second packing operation usually resulted in a nonsignificant yield increase. No difference in relative maturity was detected between any of the treatments in either years. Key words: Preseeding tillage, soil packing, pneumatic seeder, wheat
NattoKing K88 soybean
Authors: Bradner N. R. , Simpson R. D. , Hadlock A. A.
Published: April 2011

NattoKing K88, a Maturity Group I soybean (Glycine max (L.) Merr.) cultivar, yields more, has smaller seeds, lodges less and matures later than Canatto. Key words: Glycine max, NattoKing K88 cultivar
Kura clover forage yield, forage quality, and stand dynamics
Authors: Sheaffer C. C. , Marten G. C.
Published: April 2011

Persistent legumes are needed for livestock production in the northern U.S.A. and Canada. We compared forage yield, forage quality and stands of kura clover (Trifolium ambiguum M. Bieb.), a rhizomatous perennial legume, with commonly grown forage legumes. Kura clover had lower initial stands and yields than most other legumes, but was ultimately among the highest yielding legumes and had greater stand persistence and higher forage digestibility than other legumes when subjected to a diversity of cutting schedules. Key words: Kura clover, forage yield, cutting schedules, persistence
Ester- and ether-linked phenolic acids in orchardgrass (Dactylis glomerata L.) and their digestion from cell walls when fed to sheep
Authors: Kondo Tsuneo , Ohshita Tomoko , Kyuma Tadashi
Published: April 2011

Ester- and ether-linked p-coumaric (PCA) and ferulic acids (FA) in cell wall materials from orchardgrass (Dactylis glomerata L.), hays harvested at the heading stage and feces samples from sheep fed the orchardgrass hays were analyzed. Results showed that ether-linked PCA and FA were more resistant to ruminant digestion and enzymatic degradation than ester-linked PCA and FA. Key words: p-coumaric acid, esters, ethers, ferulic acid, orchardgrass, sheep digestion
Effets de la fertilisation azotée et des conditions d'application de l'éthéphon sur la productivité de la tomate de transformation cv. Heinz 2653
Authors: Tremblay Nicholas , Perron Yvon
Published: April 2011

Processing tomato crops (Lycopersicon esculentum Mill. 'Heinz' 2653) were grown during the years 1986–1988 to study the effects on fruit yield of side-dressed N rates (45, 90 or 135 kg N ha−1), ethephon spraying date (early or late) and dose (3.5 or 5.5 L ha−1). Total fruit production in 1987 was much higher than in 1986 and 1988. Early ethephon application increased by 6% the weight of #1 fruits which became more numerous, although smaller in size. The effect of the ethephon application date on yield was subject to production characteristics particular to each year. On the other hand, the effect of the ethephon dose was constant regardless of yearly conditions. The high ethephon dose did not significantly improve #1 fruit yield. Increasing N rate enhanced foliar N content but did not modify yield. It is suggested that N originating from sources other than the banded fertilizer maintained sufficient N levels for optimal growth. Key words: Ethrel, Lycopersicon esculentum, quality, ripening, yield, 2-chloroethylphosphonic acid
Residues of triallate in garlic (Allium sativum L.) cloves following preplant incorporation
Authors: Cessna Allan J.
Published: April 2011

In a 2-yr study, gas chromatography was used to determine the presence of residues of the herbicide triallate in the cloves of cured garlic (Allium sativum L.) bulbs following preplant incorporation of triallate at 2.2 kg ha−1. Triallate residues were not detected in the cloves of mature bulbs in either year. Recoveries of triallate were 82.1 ± 6.9% and 93.8 ± 4.9% from garlic clove tissue fortified at 0.1 and 0.02 mg kg−1, respectively. Key words: Triallate, garlic, residues, gas chromatography
The effects of tillage systems and crop rotations on soil water conservation, seedling establishment and crop yield
Authors: Lafond G. P. , Loeppky Heather , Derksen D. A.
Published: April 2011

The long-term productivity of soils in Western Canada can be maintained, even enhanced, providing changes in production practices occur to reverse the current trends of soil degradation. A study was initiated in 1986 to investigate the interactions of tillage systems and crop rotations on soil water conservation, seedling establishment and crop yields. The three tillage systems used were zero (ZT), minimum (one preseeding tillage operation) (MT) and conventional tillage (fall and spring preseeding tillage operations) (CT). Three 4-yr crop rotations were superimposed on the three tillage systems: fallow-spring wheat-spring wheat-winter wheat, spring wheat-spring wheat-flax-winter wheat and spring wheat-flax-winter wheat-field pea. The amount of water conserved during the fallow period was not significantly affected by tillage systems. Under stubble cropping, ZT and MT increased soil water in the 0- to 60-cm soil layer by 9% and in the 0- to 120-cm soil layer by 6% over CT. When spring soil moisture under stubble in the 0- to 120-cm soil layer was expressed as a percentage of a saturated soil profile, ZT and MT averaged 87% and CT, 82%. Seedling populations in spring wheat and field pea were not affected by tillage systems while flax seedling populations were 8% less under ZT and MT than CT. The rate of plant establishment for spring wheat was not affected by tillage systems. Yields of spring wheat, flax and field pea under ZT and MT were increased by 21, 23 and 9% over CT, respectively. Crop production practices that minimize soil degradation by maximizing the benefits of surface residues and standing stubble can successfully be adopted.Key words: Pisum sativum L., Linum usitatissimum L., Triticum aestivum L., stubble cropping, fallow cropping, crop rotation