bluuebunny/crossref_metadata_2025 huggingface dataset:
Inoculant formulation and fertilizer nitrogen effects on field pea: Crop yield and seed quality
Authors: Clayton G. W. , Rice W. A. , Lupwayi N. Z. , Johnston A. M. , Lafond G. P. , Grant C. A. , Walley F.
Published: April 2011

Appropriate rhizobial inoculation and fertility management can increase field pea (Pisum sativa) seed yield and improve yield stability in western Canada. The objective of this study was to determine the effect of inoculation method and N fertilizer application on pea seed yield and quality. The effects of soil inoculant (granular) and seed-applied inoculant (peat powder or liquid) used with and without urea-N application on field pea were investigated in the Peace River region of Western Canada. At low applied N rates, field pea biomass was significantly higher for soil-applied inoculant as compared to seed-applied inoculant. Soil-applied inoculant resulted in 15, 18, 9 and 0% higher pea biomass yield at the flatpod stage than seed-applied inoculant at 0, 20, 40 and 80 kg N ha-1, respectively. Averaged over all N rates, soil-applied inoculant resulted in 17, 50, and 56% higher pea seed yield than peat inoculant, liquid inoculant, or the uninoculated check, respectively. Soil-applied inoculant increased the proportion of the biological yield converted to seed compared to seed-applied inoculant. Seed protein concentration increased by 12 and 15% when inoculant was soil-applied compared with seedapplied or uninoculated pea, respectively. Without N fertilizer, soil-applied inoculant increased field pea biomass, seed yield and protein concentration and contributed to increasing yield stability compared with seed-applied inoculant. Key words: Granular inoculant, Pisum sativum, field pea, inoculation, seed protein, seed yield
Development and evaluation of Diplotaxis muralis (mur) cytoplasmic male sterility system in summer rape
Authors: Riungu T. C. , McVetty P. B. E.
Published: April 2011

The Diplotaxis muralis male sterility inducing cytoplasm (mur cytoplasm) and its maintainer genes were transferred from the winter rapeseed male sterile line Mangun mur CMS A-line and the mur CMS maintainer line Mangun mur CMS B-line, respectively, into summer rape lines genetically related to the open-pollinated population cultivars Regent and Karat using standard cross, backcross and test cross breeding procedures. Three genetically identical summer rape mur CMS A-line and B-line pairs, Karat I A-line and B-line, Karat II A-line and B-line and Regent A-line and B line were developed. Flower morphology studies revealed that the mur CMS A-lines had anthers displaying a complete absence of pollen and floral morphology modifications similar to that seen for other CMS systems in summer rape. Seedling emergence, days to first flower, days to maturity, and height of the vernalized mur CMS Mangun A-line and B-line pair and the summer rape mur CMS A-line and B-line pairs were similar among treatments and equal for A-line and B-line pair comparisons within cultivars for plants grown in the greenhouse. There was no evidence of biological benefits or costs associated with the mur cytoplasm. The male sterility for the vernalized Mangun mur CMS A-line and the summer rape mur CMS A-lines was stable at temperatures up to 30/24EC. Key words: Brassica napus L., male sterility, temperature stability
Resistance of canola-quality cultivars of yellow mustard, Sinapis alba L., to the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham)
Authors: McCaffrey J. P. , Harmon B. L. , Brown J. , Davis J. B.
Published: April 2011

Oilseed Bassica is susceptible to attack by the cabbage seedpod weevil while commercial yellow mustard, Sinapis alba L., is resistant. The objective of this study was to determine if canola-quality S. alba would maintain its resistance traits. In laboratory choice and nochoice tests we found the number of eggs laid by the weevil to be low or non-existent in all S. alba genotypes. Key words: Ceutorhynchus obstrictus, Ceutorhynchus assimilis, Sinapis alba, plant resistance
Effect of phosphorus treatment on growth and yield in the medicinal herb Calendula officinalis L. (Standard Pacific) under hydroponic cultivation
Authors: Stewart C. L. , Lovett-Doust L.
Published: April 2011

The North American market for herbal medicine has been rapidly growing over the past 20 yr. This has effectively created a stro ng public and regulatory demand for high quality, uniformity and safety of medicinal plant products. Greenhouse hydroponic cultivation under controlled environmental conditions allows the grower to provide pesticide-free conditions, lacking environmental contaminants, resulting in superior product quality and consistency. Calendula officinalis is evaluated here as an alternative greenhouse crop. Growing conditions (P concentrations) were manipulated in order to maximize flower-head (capitulum) yield, as the se are the most valuable marketable structures. It was found that high P concentrations did not increase flower production, but instead produced significantly more leaf biomass.Plants receiving the lowest P concentration, with an intermittent watering reg ime, had the greatest absolute reproductive output, and greatest mass of all tissues assessed, except for leaf tissue. They also had the greatest proportion of biomass allocated to reproductive structures. Calendula officinalis shows promise as a medicinal greenhouse crop that requires low P levels for optimal capitulum (inflorescence) production (target tissue). Its xerophytic characteristics are best supported through modification of standard hydroponic systems; these modifications may be widely applicab le to medicinal plants since many share Calendula’s xerophytic characteristics. We conclude that discontinuous nutrient supply and relatively low ratios of P relative to N and K may enhance production of target medicinal tissues of Calendula officinalis. Key words:
Management of nitrogen and phosphorus fertilizer in no-till flax
Authors: Lafond G. , Grant C. , Johnston A. , McAndrew D. , May W.
Published: April 2011

The major flax-growing areas of Canada coincide with areas where large shifts towards conservation tillage have occurred. These shifts have also brought about major changes in the way fertilizer is applied. The objective of this study was to determine the combination of nitrogen fertilizer form and N and P fertilizer placement methods that can increase N and P uptake, seed yield and seed oil concentration and composition in flax. The study was conducted at four locations covering the flax-growing areas over a 3-yr period. Three fertilizer forms, ammonium nitrate (AN), ammonium sulphate (AS) and urea were compared using different placement methods, pre-plant band (Pp) or side-band (Sb) in combination with monoammonium phosphate in either a Pp, Sb or seed-placed (Sp) position. Plant uptake of N and P was measured at 7, 14, 21 and 28 d after crop emergence and at the start of flowering. Other variables collected included crop establishment, crop yield and seed oil concentration and composition. AS resulted in the highest N uptake followed by AN then urea. As well, AS in the Sb showed higher N uptake than when applied Pp. The largest uptake of P was observed on days 7, 14 and 21 when AS and P were placed together in an Sb position. Crop establishment was adversely affected by urea and least by AN and AS, indicating that adequate seed-fertilizer separation between urea and flax seed is critical to minimizing reductions in plant stands. N form and placement, and P placement had no effect on seed oil concentration and composition in this study. Seed yield was improved marginally, overall, with the addition of P, while changes in N and P placement had no overall yield benefits. Treatments that resulted in improved N and P uptake in the first 21 d after crop emergence did not result in improved seed yields. When site × year interactions were investigated, 2 of 12 site years showed better yields when N and P were placed together in the Sb position. Based on the results of this study, we conclude that flax growers have many agronomically acceptable N and P management options available. Key words: Linum usitatissimum L., fertilizer placement, fertilizer form, nutrient uptake, seed yield, seed quality, oil quantity, urease inhibitor, Agrotain™
Productivity and profitability of straw-tillage and nitrogen treatments on irrigation in southern Alberta
Authors: Smith E. G. , Janzen H. H. , Entz T. , Carefoot J. M.
Published: April 2011

Straw-tillage treatment and N fertilizer rate were assessed for their impact on plant growth, N uptake, and profitability of irrigated cereals and oilseeds on a Dark Brown Chernozemic Lethbridge loam in southern Alberta. Straw was either retained or removed by baling. Tillage treatments were fall plowing, spring plowing, and direct seeding. Four N fertilizer rates (0, 50, 100, and 200 kg ha-1) were imposed on the straw-tillage treatments. The data were analyzed by crop using analysis of covariance with year and replication as random factors, straw-tillage treatment as a fixed effect, and fertilizer and fertilizer squared as covariates. Grain and straw yields were higher for fall plowing than for spring plowing or direct seeding at zero N rate, but were not different at the high N rate (200 kg ha-1). Grain and straw N concentrations were higher for fall plowing than spring plowing or direct seeding at the low N rate (50 kg ha-1), but similar at the high N rate. Total N uptake was higher for fall plowing or spring plowing without retaining straw than direct seeding without retaining straw or spring plowing with retaining straw at the low N rate, but similar at the high N rate. Net returns were higher for fall plowing and treatments that sold the straw, and were maximized at a N rate of about 100 kg ha-1. Key words: Crop residue, fertilizer nitrogen, economics, tillage timing, irrigation
Modeling vegetative development of berseem clover (Trifolium alexandrinum L.) as a function of growing degree days using linear regression and neural networks
Authors: Clapham W. M. , Fedders J. M.
Published: April 2011

Accurate models of berseem clover (Trifolium alexandrinum L.) development in relation to growing degree-days (GDD) would be useful to both producers and researchers. Predictive ability of linear regression models of plant development may be limited by choice of threshold temperature and the non-linear nature of plant development. Neural networks provide a robust approach to dealing with non-linearity, and may therefore be useful for modeling plant development. In exp.1, a numerical scale of plant development was created and used to describe growth of four cultivars of berseem clover (Bigbee, Joe Burton, Saidi and Tabor) under controlled environmental conditions (constant temperature of 12, 18 or 24°C per 12-h photoperiod) for up to 18 wk of vegetative growth. Simple linear regression and neural networks were used to model plant development in relation to GDD using a range of threshold temperatures. Predictive ability of the models was compared with the results from a second controlled environment study (exp. 2). The r2 of the linear and neural models produced in exp. 1 were maximized at GDD threshold temperatures of 0 to 2°C. Results from exp. 2 indicated that the predictive ability of neural models matched or exceeded that of the linear models for all threshold temperatures evaluated. Results of the current study suggests that neural network models are relatively insensitive to base temperatures across the range tested and may therefore be preferable when a priori knowledge of temperature thresholds is not available. Key words: Berseem clover, plant development, phenology modeling, growing degree days, base temperature, neural network modeling
Boudrias Oat
Authors: Kibite S. , Menzies J. G. , Chong J. , McCallum B. , Noll J. , Haber S.
Published: April 2011

Boudrias is a high yielding hulless oat (Avena sativa L.) with strong straw and good lodging resistance. It has a higher test weight, a higher percentage of plump groats and a lower percentage of thin groats than AC Belmont, currently the most popular hulless oat cultivar in western Canada. Boudrias has also demonstrated superior crown rust and barley yellow dwarf virus resistance than AC Belmont. In tests across western Canada, it has yielded 20% more grain than AC Belmont while maturing about a day later. Boudrias is well adapted to all regions of western Canada. Key words: Avena sativa, oat (spring), cultivar description
Predicting agronomic performance of barley using canopy reflectance data
Authors: Fetch T. G. , Steffenson Jr., B. J. , Pederson V. D.
Published: April 2011

The ability to accurately and rapidly predetermine agronomic performance would be desirable in most plant breeding programs. Remote sensing of canopy reflectance is a quick and nondestructive method that may be useful in the estimation of agronomic performance. Studies were conducted at Fargo and Langdon, North Dakota, to determine the effectiveness of a multispectral radiometer in estimating yield, kernel plumpness (KP), and 1000-kernel weight (TKW) in barley. Canopy reflectance was measured in eight (500–850 nm) discrete narrow-wavelength bands. Three types of reflectance models were evaluated: simple models using one to four wavelengths, simple ratio and normalized difference vegetation indices (NDVI) using green, red, and near-infrared wavelengths, and soil-adjusted vegetation indices (SAVI). The relationship between canopy reflectance and agronomic performance was significantly influenced by environment, growth stage, and plant genotype. Grain yield was best estimated near GS73 (0.84 < R2 < 0.92) at Fargo and at GS83 (0.55 < R2 < 0.81) at Langdon. In contrast, KP and TKW could be estimated at both late (GS83; 0.68 < R2 < 0.93) and early (GS24–GS47; 0.72 < R2 < 0.91) growth stages. The 550-nm and 800-nm wavelengths are critical for development of predictive models. A simple model using 550-nm, 600-nm, and 800-nm from GS47-GS73 gave significant (0.45 < R2 < 0.64) estimation of agronomic performance across all environments. In contrast, simple ratio, NDVI, and SAVI were less effective (0.05 < R2 < 0.77) in predicting agronomic performance. Remote sensing using canopy reflectance is a potential tool to estimate agronomic performance of barley, but genotypic and crop stage factors affect this method. Further studies are needed to improve the usefulness of multispectral radiometry in predicting agronomic performance. Key words: Crop yield, Hordeum vulgare, kernel plumpness, remote sensing
Reduction of the available phosphorus pool in field soils growing maize genotypes with extensive mycorrhizal development
Authors: Liu A. , Hamel C. , Elmi A. A. , Zhang T. , Smith D. L.
Published: April 2011

Arbuscular mycorrhizal fungi (AMF) have a large enhancing effect on the P uptake capacity of host plants, which could make possible the production of high crop yields on soil with reduced level of available P, or could help reduce the P level in rich soils, thereby reducing the risk of P loss to the environment. A field experiment was conducted in Ste-Anne-de-Bellevue, Quebec, Canada, on a loamy sand in 1997 and a fine sandy loam in 1998 to assess the impact of indigenous AMF-maize hybrid combinations on soil available P level. The experiment had three factors organized in a split-split plot design. There were two soil fumigation levels (fumigated and non-fumigated) randomized in the main plots, three P fertilizer rates (0, 60, and 120 kg ha-1) randomized in the sub-plots and three maize (Zea mays L.) hybrids with contrasting genotypes [two newly developed leafy hybrids, Leafy normal stature (LNS) and Leafy reduced stature (LRS), and a commercial hybrid, Pioneer 3979 (P3979)], which were randomized in the sub-sub-plots. Soil extractable P, plant P content, plant dry mass, root colonization with AMF and extraradical hyphae were determined at the 6-leaf, 10-leaf, tasselling and silking stages of maize, and grain yield and total P in maize were determined at harvest. Soil fumigation to reduce AMF and P fertilization reduced the amount of indigenous mycorrhizal development in maize hybrids. The growth of LNS, the most mycorrhizae-dependent hybrid, was more supressed by fumigation than the growth of the other two hybrids. When the soil P level was low, plant dry mass, grain yield and total P content of LNS were higher in the non-fumigated plots than in the fumigated plots. Fumigation had a significant but smaller influence on soil extractable P level than on plant P uptake and growth. Soil extractable P was lower in non-fumigated plots than in fumigated plots from silking to the end of the growing season in 1997, only in non-fertilized plots growing LNS. Extraradical hyphae density was positively correlated with maize P uptake and negatively correlated with soil extractable P. This suggested that soil extractable P can be reduced through AMF-enhanced plant P uptake when soil available P conditions and host plant genotype are favourable to mycorrhizal development, and when P uptake enhancement is large. Key words: Arbuscular mycorrhizal fungi, maize hybrids, soil extractable P, P uptake, extraradical hyphae, root colonization, mycorrhizal dependency
Effect of altitudinal gradient on yield and quality of sub-alpine meadow on the Xiaowutai Mountain in northern China
Authors: Yuan Jiang Shi-kui Dong, , Liu Quan-ru , Huang Xiao-xia
Published: April 2011

Herbage yield increased with elevation from 2200 to 2600 m and then declined until 2800 m. Altitude did not affect herbage fat, acid detergent fibre, calcium or sulphur concentrations, but did influence herbage organic matter, crude protein and phosphorus concentrations. It is recommended that livestock should be rotationally grazed along an altitudinal gradient on Xiaowutai Mountain to meet their dry matter (DM) and nutrients requirements in summer grazing systems. Key words: Herbage biomass, crude protein, acid detergent fibre, minerals
Effect of NaCl on growth, morphology, and camptothecin accumulation in Camptotheca acuminata seedlings
Authors: and Zhanhai Li , Liu Zhijun
Published: April 2011

NaCl salt is shown to increase alkaloid accumulation in some plant species, but creates an extensive problem in plant cultivation. The effect of NaCl on Camptotheca acuminata Decaisne growth, morphology, and camptothecin accumulation (concentration and yield) was studied in a hydroponic culture system. High NaCl levels (above 75 mM) in growth media significantly reduced plant height, weight, leaf number, and leaf length but increased leaf weight. In contrast, low NaCl levels (below 75 mM) only moderately reduced growth and affected morphology. Our results suggest a concentration of 75 mM is the threshold for NaCl to exert a detrimental effect on C. acuminata seedlings. Furthermore, high NaCl levels (above 75 mM) increased camptothecin concentrations both in leaves and roots, whereas low NaCl levels (below 75 mM) had no effect on camptothecin concentrations. However, total leaf camptothecin yield, the product of leaf camptothecin concentration and total leaf dry weight per seedling, decreased with increasing NaCl concentration. There was a negative relationship between plant growth and camptothecin concentration. Our results suggest that high NaCl salinity increases camptothecin concentration, but is not helpful to achieve a high camptothecin yield. Therefore, a salty growth environment should be avoided for camptothecin production. Key words: Alkaloid, anti-cancer plant, HPLC, plant secondary metabolism
Tolerance of lowbush blueberries (Vaccinium angustifolium Ait.) to drought stress. II. Leaf gas exchange, stem water potential and dry matter partitioning
Authors: Glass V. M. , Percival D. C. , Proctor J. T.A.
Published: April 2011

A 2-yr field study examining the effect of soil moisture on plant water status, photosynthesis and gas exchange parameters in lowbush blueberry (Vaccinium angustifolium Ait.) was conducted at the Nova Scotia Wild Blueberry Institute (NSWBI), Debert, NS. Drought and irrigation treatments were applied over two years in either or both the vegetative and cropping years of production. Midday stem water potential values indicated that all treatments resulted in drought stress. Mean stem water potential values ranged from -1.41 to -1.45 MPa. Predawn stem water potentials in the vegetative growth season indicated that although some recharging and recovery of water loss occurred overnight, the drought-stressed plants did not fully return to pre-stress levels under the moisture-limiting conditions. Higher chlorophyll a and b levels were observed in the single-season drought treatment. Leaves of irrigated plants in both sprout and crop years had the highest stomatal density. There were no differences in photosynthetic rate (Pn) among treatments despite the lower stomatal conductance resulting from limited soil moisture. Key words: Photosynthesis, stomate, stem water potential
Identification of phytotoxic substances in soils following winter injury of grasses as estimated by a bioassay
Authors: Brandsæter L. O. , Haugland E. , Helgheim M. , Gudleifsson B. E. , Tronsmo A. M.
Published: April 2011

Under northern conditions, winter survival of grass species for hay production is quite uncertain because of winter stresses to plants. Damage to plants may be caused by variability in snow cover, low temperatures, ice encasement and pathogens. Compared to renovation by ploughing, direct drilling without ploughing has some beneficial aspects and may be an alternative method for renovating hay fields. However, successful establishment of grasses without ploughing has been difficult to achieve both in scientific studies and under practical conditions. The objective of this investigation was to study whether a dead grass sod, killed by different winter injuries, may leak phytotoxins into the soil, thus causing the poor results observed by direct drilling in hayfields. Experiments, including soil water extraction and the use of bioassays, were conducted in growth chambers, to study the effects of the winter stresses frost, ice encasement, and snow mould on the accumulation of potentially phytotoxic biochemical compounds in the soil. Snow mould did not kill the grasses in the experiments and no phytotoxicity was measured. Although both ice encasement and low temperatures killed the grasses, only ice encasement caused phytotoxicity. The present investigation shows that the occurrence of phytotoxic substances, especially butyrate, after ice encasement may be a cause of poor establishment of direct-drilled grass plants after winter injuries. In serious cases of ice encasement this may justify a 1-2 wk delay of sowing, which in turn may result in reduced soil water for germination and may cause increased competition from other species. Key words: Hay fields, grassland, winter injuries, phytotoxic substances, allelochemicals
Response of processing carrot to metribuzin on mineral soils in Nova Scotia
Authors: Jensen K. I. N. , Doohan D. J. , Specht E. G.
Published: April 2011

Metribuzin was examined as an alternative to linuron and prometryn when prometryn-treated processed carrot in Atlantic Canada in the 1990s could not be exported to the United States, where prometryn was not registered for this crop. Field studies demonstrated that 280 g ha-1 metribuzin applied after the three-leaf crop stage resulted in only minor injury and no yield loss for both a metribuzin-tolerant (Caro-Choice) and -sensitive (Dominator) cultivar. Metribuzin applied either pre- or post-emergence controlled two Matricaria species, chickweed [Stellaria media (L.) Vill.] and shepherd’s-purse [Capsella bursa-pastoris (L.) Medik.], equivalent to approved prometryn and linuron treatments. Controlled environment studies were conducted to examine the effect of crop growth stage, temperature and soil pH on metribuzin injury to carrot. Differential tolerance between the two cultivars occurred only up to the three-leaf stage. Under controlled environment conditions, carrot injury to metribuzin increased threefold as soil pH increased from 6.5 to 7.4. There was little injury when metribuzin was applied postemergence under cool temperatures (15/10°C), but injury increased from 25 to 85% under 20/15°C and 30/25°C regimes. Lower temperatures and naturally low pH soils contribute to carrot tolerance to metribuzin under Nova Scotia conditions. Based on this research, metribuzin at 280 g ha-1 applied after the three-leaf stage of carrot was approved for use in the Atlantic provinces. Key words: Daucus carota L., cultivar tolerance, soil pH effects, temperature effects, weed control
The dune race of Vitis riparia in Ontario: Taxonomy, conservation and biogeography
Authors: Catling Paul M. , Mitrow G.
Published: April 2011

Although poorly known, the native dune grape, Vitis riparia Michaux var. syrticola (Fernald & Wiegand) Fernald, is a potentially important source of valuable traits for the improvement of cultivated grapes. In order to clarify its taxonomic and conservation status in Ontario and to evaluate ecological and geographic patterns, data were collected from 623 specimens from 10 herbaria. In addition, five plants referable to var. syrticola with densely hairy petioles and five referable to var. riparia with glabrous petioles were cultivated in a greenhouse under uniform mesic conditions. Although the sample was considered reliable, there was no bimodal pattern in the putatively distinctive dense pubescence to support taxonomic recognition of var. syrticola; it may be referred to simply as “the dune race.” Cultivated plants retained their initial pubescence characteristics for 3 consecutive years, suggesting that the character is relatively stable. Plants referable to the dune race with dense pubescence occurred in extremely dry and open natural habitats and occurred significantly more often than expected on shoreline sand dunes of the Great Lakes. In contrast, plants without hair or less pubescent were significantly under-represented in dry habitats and shoreline dunes. While Vitis riparia is widespread in southern Ontario, the pubescent race is restricted and has a predominantly Great-Lakes-shoreline distribution pattern. It has been reported from only 43 locations and is considered vulnerable to decline. Key words: Grape, Vitis, Ontario, germplasm protection, crop relative
The reactions of Canadian spring wheat genotypes to inoculation with Claviceps purpurea, the causal agent of ergot
Authors: Menzies J. G.
Published: April 2011

Ergot, caused by Claviceps purpurea, can be a detrimental pathogen of wheat because the sclerotia of this fungus are toxic to animals and humans. The purpose of this work was to determine if currently registered Canadian wheat cultivars and experimental wheat lines differ in their reactions to C. purpurea and to determine if different classes of wheat [Canadian Western Red Spring (CWRS), Canadian Prairie Spring (CPS), Canadian Western Extra Strong (CWES), Canadian Western Soft White Spring (CWSWS), and Canadian Western Amber Durum (CWAD)] differ in their levels of resistance. Fifty-four wheat genotypes from different western Canadian classes of wheat were inoculated with a mixture of six isolates of C. purpurea and assessed for the number of sclerotia produced per spike and rated for sclerotial size produced and the amount of honeydew produced. In general, CWAD wheats produced significantly fewer sclerotia per spike and the CWSWS wheats had significantly smaller sclerotia. None of the classes differed in honeydew production. One CWAD genotype, 9260B-173A, had the fewest sclerotia, and the lowest ratings for sclerotial size, and amount of honeydew produced compared to the other wheat genotypes tested. Key words: Hexaploid wheat, durum wheat, Triticum turgidum var. durum, T. aestivum, ergot, Claviceps purpurea, resistance, sclerotia size, honeydew
Managing phosphorus for yield and quality of sweet corn grown on high phosphorus soils of Maryland's eastern shore
Authors: Geleta Samuel B. , Brinsfield Russell B. , Ron Mulford F. , Womack Harry E. , Briand Christopher H. , O’Keefe Jennifer A.
Published: April 2011

Reducing P fertilization to address water quality problems has raised concerns among producers regarding crop yield and quality. A 3 yr study was conducted at three sites to examine whether reduction in P fertilization rate and/or use of a preceding rye cover crop affect the yield and quality (sugar concentration and ear weight) of sweet corn (Zea mays L.) grown on soils with “excessive” plant-available P. The experimental design was a split plot with four replications conducted on Norfolk soils. The main plots were no cover crop and a rye cover crop. The subplots were five P fertilizer treatments ranging from 0 to 60 kg P ha-1 at 15 kg P increments. With or without a preceding rye cover crop or P fertilization, postharvest soil test P (Mehlich-1) levels remained “excessive” to a depth of 40 cm. Also, yield of sweet corn was not affected by P fertilization and/or use of a preceding rye cover crop. Without cover cropping, sugar content and ear weight response to P fertilization was positive on site 2 for sugar, and on sites 2 and 3 for ear weight. Utilization of cover cropping positively influenced sweet corn sugar and ear weight sampled at early milk stage without affecting the final yield. In processing sweet corn production, profitability is determined mainly by the yield of marketable ears. Therefore, the small, inconsistent increases in sugar content and ear weight in response to P fertilization, without an increase in yield is not of a major significance to the farmer. On high P soils, P fertilization is unnecessary for the production of quality, high-yield processing corn. The use of a rye cover crop is suggested as a method of reducing the risk of P loss into the surrounding watershed. Key words: Sweet corn yield, sweet corn quality, P fertilization, rye cover crop, phosphorus management, high P soils
Rate and timing of nitrogen fertilization of Russet Burbank potato: Yield and processing quality
Authors: Zebarth B. J. , Leclerc Y. , Moreau G. , Botha E.
Published: April 2011

Split fertilizer N application is thought to improve fertilizer N use efficiency of potato, primarily by reducing NO3 leaching losses. This study evaluated the effects of the rate and timing of N fertilization on yield and processing quality of Russet Burbank potato under rain-fed production. Trials conducted in 1999–2001 included different fertilizer N rates (0–160 kg N ha-1 in 1999 and 0–200 kg N ha-1 in 2000 and 2001) applied either at planting according to normal grower practice, or at hilling, the latest time that granular fertilizer can practically be applied. Tuber total and marketable yield, size distribution, specific gravity, fry colour and tuber concentrations of NO3, sucrose and glucose were measured. Increasing rates of N fertilization increased tuber yield and tuber size, increased tuber NO3 concentration and decreased tuber specific gravity, but had little effect on tuber sugar concentrations or fry colour. Season-to-season variations in total tuber yield responses to N fertilization rate were attributed primarily to variation in soil N supply. Timing of N application had little effect on tuber yield, size distribution or processing quality under adequate soil moisture conditions. However, under dry soil conditions, split N application reduced tuber yield and tuber size. Key words: Solanum tuberosum, tuber specific gravity, tuber nitrate concentration, fry colour
Managing arbuscular mycorrhizal fungi in cropping systems
Authors: Plenchette C. , Clermont-Dauphin C. , Meynard J. M. , Fortin J. A.
Published: April 2011

Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between these fungi and plant roots, are directly involved in plant mineral nutrition, the control of plant pathogens, and drought tolerance. Most horticultural and crop plants are symbiotic with arbuscular mycorrhizal fungi. Mycorrhizal literature is abundant, showing that stimulation of plant growth can be mainly attributed to improved phosphorous nutrition. Although the mycorrhizal potential of its symbiosis to improve crop production is widely recognized, it is not implemented in agricultural systems. There is an urgent need to improve and widely apply analytical methods to evaluate characteristics such as, relative field mycorrhizal dependency, soil mycorrhizal infectivity, and mycorrhizal receptivity of soil. Decreased use of fertilizers, pesticides, and tillage will favour arbuscular mycorrhizal fungi. However, shifting from one system to a more sustainable one is not easy since all components of the cropping system are closely linked. Different cases, from actual agricultural practices in different countries, are analyzed to highlight situations in which mycorrhizae might or might not play a role in developing more sustainable agriculture. Key words: Cropping systems, mycorrhizae, sustainability, technical itineraries, rotation
Effect of photoselective filters on the physical and chemical traits of vine-ripened tomato fruits
Authors: Gautier Hélène , Rocci Aline , Buret Michel , Grasselly Dominique , Dumas Yvon , Causse Mathilde
Published: April 2011

The effects of several wavelength selective light filters placed on developing mature green tomato fruits were studied to determine whether light environment during fruit ripening has an impact on fruit composition. Juice titratable acidity and fruit fresh and dry weight varied little with the different filters. Reducing the red/far-red light ratio with a green filter to simulate vegetation shade slightly delayed ripening. Reducing infrared light (700-1100 nm) reduced vitamin C and soluble sugars content. A drastic reduction in photosynthetic light (97%) reduced both β-carotene (-23%) and lycopene (-29%) contents and red coloration (-21%). Significant correlations were found among the content of soluble sugars, vitamin C and lycopene, but these components increased differently according to the spectral composition of the light transmitted to the fruit. The content of lycopene and β-carotene increased with exposure to photosynthetic radiation and more precisely with exposure to blue light. In contrast, the content of vitamin C and sugar increased with infrared light exposure. Key words: β-carotene, photoselective filters or shading, fruit ripening, fruit environment, lycopene, Lycopersicon esculentum, tomato, vitamin C
On-farm production and utilization of arbuscular mycorrhizal fungus inoculum
Authors: Douds Jr. D. D. , Nagahashi G. , Pfeffer P. E. , Kayser W. M. , Reider C.
Published: April 2011

Arbuscular mycorrhizal (AM) fungi colonize the roots of the majority of crop plants, forming a symbiosis that potentially enhances nutrient uptake, pest resistance, water relations, and soil aggregation. Inoculation with effective isolates of AM fungi is one way of ensuring the potential benefits of the symbiosis for plant production. Although inocula are available commercially, on-farm production of AM fungus inoculum would save farmers the associated processing and shipping costs. In addition, farmers could produce locally adapted isolates and generate a taxonomically diverse inoculum. On-farm inoculum production methods entail increasing inoculated isolates or indigenous AM fungi in fumigated or unfumigated field soil, respectively, or transplanting pre-colonized host plants into compost-based substrates. Subsequent delivery of the inoculum with seed to the planting hole in the field presents technological barriers that make these methods more viable in labor-intensive small farms. However, a readily available method for utilization of these inocula is mixing them into potting media for growth of vegetable seedlings for transplant to the field. Direct application of these inocula to the field and transplant of seedlings precolonized by these inocula have resulted in enhanced crop growth and yield. Key words: AM fungi, sustainable agriculture, biofertilizer
Arikara Yellow common bean
Authors: David Gehl Hans-Henning Mündel, , Huang Henry C. , Conner Robert L.
Published: April 2011

Arikara Yellow is an early-maturing heritage bean (Phaseolus vulgaris L.) cultivar with a tan-yellow seed belonging to the Canario mexicano (syn. Mantequilla) market class. It has a determinate bush type growth habit, with wide adaptation on the Canadian prairies. Arikara Yellow is resistant to white mould caused by Sclerotinia sclerotiorum (Lib.) de Bary and to three of four common races of anthracnose, caused by Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. Key words: Common bean, Phaseolus vulgaris, heritage bean, cultivar description
Placement, rate and source of N, seedrow opener and seeding depth effects on canola production
Authors: Malhi S. S , Gill K. S
Published: April 2011

Seedrow-placement of N fertilizer can save money and time, but it can cause reduced emergence and yield. From 1998 to 2000, a field experiment was conducted on a silty clay loam (Black Chernozem) soil at Melfort, Saskatchewan. The objectives were to determine the influence of placement, rate and source of N, seedrow opener and seeding depth on the emergence, yield, N uptake, and seed protein and oil content of canola (Brassica napus L. ‘Quest’). The treatments were optimum (1.5 cm) and deep (4.5 cm) seeding depths in two main plots with 17 subplots of different combinations of N sources [urea and ammonium nitrate (AN)], rates (0, 40, 80 and 120 kg N ha-1) and placements (sideband and seedrow) using two seedrow openers (knives – 2 cm spread, and shovels – 20 cm spread). Sidebanding of 40, 80 and 120 kg N ha-1 and seedrow placement of 40 kg N ha-1 increased yield, N uptake and seed protein content, had no detrimental effect on emergence, and reduced seed oil content. Compared to sidebanding, seedrow placement of 80 and 120 kg N ha-1 generally reduced emergence, yield and N uptake, with relatively severe effect at higher N rate, but had no effect on seed protein and oil content. The yield and N uptake of canola responded up to 120 kg N ha-1 with sidebanding compared to 40 kg N ha-1 for yield and 80 kg N ha-1 for N uptake with seedrow placement. Deep seeding reduced emergence, yield and N uptake in many cases, had no effect on seed protein content and reduced oil content in some treatments. At low rates of N, emergence was generally better with knives, while shovels tended to be superior at higher rates of seedrow-placed N. In general, the negative impact of seedrow placement compared to sideband placement of N was more severe with deeper seeding, higher N rate and narrower width of seedrow placement band. In summary, the findings indicated that practices that placed seed and fertilizer in a way that maximized canola emergence and minimized seedling damage from fertilizer, consistently optimized seed yield response to N fertilizer. Key words: Canola, N placement, N rate, N source, seeding depth, seedrow opener
Development of a laboratory baking test for Uruguayan French style hearth bread using Canadian wheat flour
Authors: Paulley G. , Vázquez D. , Lysenko E. , Preston K. R.
Published: April 2011

Straight grade Canadian wheat (Triticum aestivum L.) flours milled from a high and medium protein Canada Western Red Spring (CWRS) wheat, a commercial sample of Canada Prairie Spring Red (CPSR) wheat and a recently released CPSR variety, 5700PR, were used to develop and assess the impact of absorption, fermentation time and flour type on a laboratory-scale Uruguayan French style hearth bread baking procedure. The lean formula dough, containing flour, yeast, ascorbic acid, malt, yeast food and optimum water absorption as determined by dough feel, was mixed to peak development in a GRL 1000 mixer, fermented, and divided into multiple (175-g) pieces. Dough pieces were sheeted and moulded using a commercial hearth bread moulder, proofed, cut (diagonal top surface cut) and baked in a modified National laboratory oven equipped with steam. Optimum dough absorption for all four flours was 62% in spite of a wide range in farinograph absorption. Optimum fermentation time was 75 min based on moulded dough length, bread volume and form, cut width and crumb texture and colour. The lower protein CWRS and the CPSR variety, PR5700, showed superior overall performance relative to the other wheat flours. The performance of the commercial CPSR flour was clearly inferior to all other wheat flours. Excellent reproducibility was obtained for all measured parameters allowing good discrimination among samples. This baking procedure should prove useful in assessing the performance of Canadian wheat classes and varieties for Uruguay and other South American markets where similar bread is popular. Key words: Triticum aestivum L., wheat, baking, hearth bread, Uruguayan bread, Canadian wheat, Canada Western Red Spring, Canada Prairie Spring Red
Net Cd2+ flux at the root surface of durum wheat (Triticum turgidum L. var. durum) cultivars in relation to cultivar differences in Cd accumulation
Authors: Farrell R. E. , McArthur D. F.E. , Van Rees K. C.J.
Published: April 2011

Net Cd2+ flux and Cd accumulation for four durum wheat cultivars were measured to determine whether the net Cd2+ flux to the roots plays a role in cultivar differences in Cd accumulation. Plants were germinated for 4 d in the dark and then grown hydroponically for 2 d before being placed in a Petri dish with their roots immersed in a 1.0 µM Cd solution. Net Cd2+ flux to the root was measured at ten positions located 0.5 mm to 25 mm from the root tip. Cadmium concentrations were measured using Cd2+-selective microel ectrodes; Cd2+ flux to the root surface was then calculated using the MIFE™ system. The flux was greatest nearest the root tip (within 1.5 mm of the tip) and there were no significant differences in net Cd2+ flux among the various cultivars — likely because of the absence of a Casparian strip in the root tip cells. Net Cd2+ flux decreased with increasing distance from the root tip, with significant differences among cultivars. The mean Cd2+ flux to the roots in the 2–25 mm region increased in the following order: Arcola ≈ G9265-AU ≈ Kyle < G9265-BF, with the low grain Cd accumulators (Arcola and G9265-AU) generally exhibiting lower fluxes than the high grain Cd accumulators (Kyle and G9265-BF). However, net Cd2+ flux did not correspond to total plant Cd content, which increased in the order: G9265-AU < G9265-BF < Kyle < Arcola. We conclude that while there are durum wheat cultivar differences in the net Cd2+ flux at the root surface, their contribution to cultivar differences in total plant Cd accumulation is generally overshadowed by one or more other Cd accumulation factors. Key words: Cadmium, microelectrodes, plant cadmium content, cadmium flux, durum wheat, cultivar
Influence of seeding date and harvest stage on yields and essential oil composition of three cultivars of dill (Anethum graveolens L.) grown in Nova Scotia
Authors: Bowes Kelly M. , Zheljazkov Valtcho D. , Caldwell Claude D. , Pincock James A. , Roberts Jeffrey C.
Published: April 2011

Experiments were conducted in two locations in Nova Scotia, Canning and Truro, during 2001 and 2002 to determine the effect of seeding date and harvest stage on productivity and composition of essential oil from Anethum graveolens L. ‘Mesten, Dukat’ and ‘Hercules’. Delayed seeding generally reduced yields and altered the concentration of some essential oil components. Both dill seed and dill weed oil from this study had compositions similar to commercially available oil and reported dill oil compositions. The seed oil had moderate to high carvone content (17.9–64.0%) as is desired for the international market. Carvone content in oil increased as the plants matured. Lower yields and essential oil yields were obtained from cv. Hercules compared with the other two cultivars. Herbage yields and essential oil content were typical for the plant species; seed yields were below average, but there is potential to increase these yields through different seeding dates, harvest dates and investigation into optimum nutrient requirements. Key words: Dill, Anethum graveolens, Apiaceae, essential oil, hydrodistillation, steam distillation
Effect of durum wheat (Triticum turgidum L. var. durum) semolina extraction rate on semolina refinement, strength indicators and pasta properties
Authors: Dexter J. E. , Doust M. A. , Raciti C. N. , Lombardo G. M. , Clarke F. R. , Clarke J. M. , Marchylo B. A. , Schlichting L. M. , Hatcher D. W.
Published: April 2011

Since the 1980s, there have been general trends in the durum wheat milling industry to higher semolina extraction rate, and in the pasta processing industry to the use of higher drying temperatures. During this time, specification of gluten strength by gluten index, mixograph mixing properties and alveograph parameters has also become widespread. These trends prompted this study of the appropriateness of protocols for quality testing of Canadian durum wheat breeding lines. Four cultivars with intrinsic differences in yellow pigment levels and gluten strength were grown in field plots in Swift Current, Saskatchewan for three consecutive years. A laboratory-scale milling procedure was modified to produce semolina at extraction rates from about 65% to about 80%. Milling to extraction rates above 65%, the extraction rate used routinely in quality testing of Canadian durum wheat breeding lines, had a major impact on semolina ash content and colour, but did not offer any advantage in ranking cultivars for either semolina yield or semolina refinement. Gluten strength, as measured by gluten index, was independent of semolina extraction rate. Dough strength, as measured by mixograph properties and alveograph properties, showed a tendency to weakening at high extraction, particularly for strong cultivars. Semolina was processed into spaghetti using low-temperature (LT), high-temperature (HT) and ultra-high-temperature (UHT) drying cycles. The firmness of cooked spaghetti was predominantly influenced by protein content. As a result, cultivars generally ranked in spaghetti firmness according to protein content. Regardless of drying cycle or cultivar, spaghetti firmness increased as drying temperature increased. Spaghetti dried at LT was less yellow than spaghetti dried at HT or UHT, probably due to thermal inactivation of the bleaching enzyme lipoxygenase at HT and UHT. Regardless of drying cycle, spaghetti became duller, more red and less yellow as extraction rate increased. For each spaghetti trait, cultivar ranking remained relatively constant regardless of extraction rate or drying temperature. On the basis of these results, there appears to be no advantage to increasing semolina extraction rate beyond 65% for evaluation of durum wheat milling performance, gluten strength or pasta properties. In addition, it appears that one drying cycle is adequate to reliably evaluate durum wheat lines for spaghetti colour and firmness. Key words: Durum wheat (Triticum turgidum L. var durum), milling, semolina, pasta, quality screening, gluten strength, colour, texture