Clubroot, caused by Plasmodiophora brassicae, was detected for the first time on canola in Alberta. Galling, typical of the disease, was observed on the roots of canola (Brassica napus) plants in a dozen fields near St. Albert, Alberta. The presence of resting spores of the pathogen was confirmed by light and electron microscopy. Pathogen spores were isolated from diseased tissue and used to inoculate roots of B. napus 'Westar', on which they produced symptoms similar to those observed in the field. Resting spores were recovered from galls on inoculated plants. The identification of clubroot on the Alberta canola crop is a matter of concern, as the disease is associated with appreciable yield losses and can only be managed with extended intervals between host crops because other management strategies may be too expensive to implement or are of limited effectiveness. Further studies are underway to determine the extent of the problem.Résumé : La hernie, causée par le Plasmodiophora brassicae, a été trouvée pour la première fois sur le canola en Alberta. Typique de la maladie, la formation de galles a été observée sur des racines de canola (Brassica napus) dans une douzaine de champs près de St. Albert, Alberta. La présence de spores de conservation de l'agent pathogène a été confirmée par microscopies optique et électronique. Des spores de l'agent pathogène ont été isolées de tissus malades et utilisées pour inoculer des racines de B. napus 'Westar' sur lesquelles elles ont causé des symptômes semblables à ceux observés au champ. Des spores de conservation ont été retrouvées dans des galles de plantes inoculées. L'identification de la hernie dans les cultures de canola de l'Alberta est préoccupante puisque la maladie est associée à d'importantes pertes de rendement et ne peut être combattue que par de longs intervalles sans cultures sensibles, étant donné que les autres stratégies de lutte sont trop coûteuses ou d'efficacité restreinte. D'autres études sont en cours pour déterminer l'ampleur du problème.
Relatively high seed prices and low canola (Brassica napus L.) grain prices created a controversy over using farm-saved seed from hybrids. Agronomic implications of saving seed from a canola crop were investigated by planting certifi ed seed and saved-seed of an open-pollinated and a hybrid canola cultivar at eight site-years in Saskatchewan and Alberta, Canada. In one series of experiments cultivars and seed rates were compared, while in another experiment seed treatments and use of sized seed were investigated. Results tend to agree with similar studies with other crops where agronomic performance was unaff ected when farm-saved seed from open-pollinated crops was used, but declined when this practice was used with hybrid cultivars. Using farm-saved seed from hybrid canola (HY-FSS) compared with hybrid certifi ed seed (HYC) reduced plant population density by 16 to 18% at the time of crop maturity and yield by an average of 12%, delayed maturity by 2 d, reduced seed oil content by 5 g kg -1 , and resulted in a small increase in incidence of green seed. Yield and quality loss associated with using HY-FSS could not be recovered by using increased seeding rates or by sizing and planting only large seed. Th e inability to use the most eff ective combined insecticide plus fungicide seed protectant treatments with farm-saved seed resulted in a 20% yield loss compared with treated certifi ed hybrid seed. Our study demonstrates the production risks of growing HY-FSS on plant density, yield, maturity, and seed oil content.
Broadcast-incorporated N was more susceptible to immobilization by the soil than was deep-banded N.
Harker, K. N., O'Donovan, J. T., Blackshaw, R. E., Hall, L. M., Willenborg, C. J., Kutcher, H. R., Gan, Y., Lafond, G. P., May, W. E., Grant, C. A., Barthet, V., McDonald, T., Wispinski, D. and Hartman, M. 2013. Effect of agronomic inputs and crop rotation on biodiesel quality and fatty acid profiles of direct-seeded canola. Can. J. Plant Sci. 93: 577–588. A field study was conducted at eight sites in western Canada to determine the influence of agronomic inputs on fatty acid profiles and biodiesel quality of canola. Protein and chlorophyll concentration and fatty acid profiles were determined from seed samples at all sites. Oil was extracted from canola seed samples from three sites, converted to biodiesel, and subjected to standard protocols. Protein concentration increased at higher than recommended rates of nitrogen (N) and the higher canola seeding rate (150 seeds m−2) reduced chlorophyll levels in canola oil. All biodiesel samples fell below new oxidation stability tolerance levels (minimum 8 h). However, given the routine addition of commercial antioxidant additives, all biodiesel samples from this study were suitable for blending in middle distillate fuels. Cloud point values were lowest at normal N (1×) rates. Normal N rates increased stearic acid content, whereas high N rates (1.5×) increased gadoleic acid content. Low seeding rates (75 seeds m−2) increased palmitic acid content. The combination of normal N (1×) with a high seed rate (150 seeds m−2) increased oleic acid content. Conversely, the combination of high N (1.5×) with a low seed rate (75 seeds m−2) increased linolenic acid content. Gadoleic acid content increased in the continuous canola rotation versus the canola–wheat–canola rotation; similar trends were observed with palmitic, linoleic, and linolenic acid. Oleic acid tended to be higher in canola rotated with wheat. Cold filter plugging point (CFPP) was predicted based on saturated fatty acid content. Usually, a high seeding rate (150 seeds m−2) combined with a normal N rate (1×) led to the most favourable (lowest) CFPP values. Low CFPP values were also associated with canola rotated with wheat compared with continuous canola production. Seeding rate, N, and crop rotation influenced protein and chlorophyll concentration, fatty acid profiles, cloud point, and CFPP.
A canola (Brassica napus L.) experiment to determine the effect of unconventional or novel inputs compared with standard and increased seed and nitrogen rates was conducted at 14 different Alberta and Saskatchewan, Canada sites in 2013 and 2014. All treatments were compared to a "best management practice" (BMP) treatment with canola seeded at 100 seeds m −2 and fertilized according to soil test recommendations. Canola density across all sites averaged 56 plants m −2 and increased to 76 plants m −2 at 150 seeds m −2. Flowering and maturity time were both decreased when 25% less nitrogen was applied in the side-band at seeding. Compared to the BMP treatment, there were trends for lower yield (P = 0.0528) when side-banded nitrogen was reduced by 25% at seeding time or for higher yield (P = 0.0530) when 25% more nitrogen was added as a foliar treatment at the bud stage. Canola yields were generally economically optimized in the BMP treatment at soil test recommended nitrogen rates. Increasing the seeding rate from 100 to 150 seeds m −2 did not increase canola yield; however, it did decrease % green seed enough to potentially affect canola grade and economic returns. Increasing or decreasing nitrogen fertilizer compared to BMP often decreased or increased seed oil concentration, respectively, and had the opposite effect on seed protein concentration. Despite incurring additional costs compared to the BMP treatment, none of the novel inputs impacted canola emergence, days to flowering, days to maturity, yield or quality.
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