Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

Gene flow in commercial fields of herbicide‐resistant canola (brassica napus)

Abstract: Multiple herbicide resistance to glyphosate, glufosinate, bromoxynil, or imidazolinone in volunteer plants of canola (Brassica napus) has been attributed to pollen flow among cultivars with different resistance traits. A study was conducted in Saskatchewan, Canada, in 1999 and 2000 to assess gene flow in space and time in adjacent commercial fields of glyphosate- and glufosinate-resistant canola, including (1) estimation of gene flow with distance; (2) frequency and distribution of volunteers, and effect on gene flow; (3) effect of adventitious double herbicide-resistant seed presence in seedlots planted; and (4) a comparison of various marker systems to track gene flow events. At 11 sites in 1999, gene flow was determined by sampling seeds from plants located at 0, 50, 100, 200, 400, 600, or 800 m along a transect perpendicular to the common border in the paired fields, spraying seedlings with glyphosate and glufosinate, and confirming the presence of the transgenes using commercial test strips and PCR analysis. In the spring of 2000, putative double herbicide-resistant volunteers that survived sequential herbicide applications were mapped at three of the sites using GPS and resistance in sampled plants was characterized. In 1999, gene flow between the paired fields was detected to a maximum distance of 400 m. Values ranged from 1.4% outcrossing at the border common to the paired fields to 0.04% at 400 m. In 2000, gene flow as a result of pollen flow in 1999 was detected to the limits of the study areas (800 m). Large variation in gene flow levels and patterns among the three sites was evident. Adventitious presence of double herbicide-resistant seed in glyphosate-resistant seedlots planted at two of the sites in 1999 contributed to the occurrence of double herbicide-resistant volunteers in 2000. The results of this study suggest that gene stacking in B. napus canola volunteers in western Canada may be common, and reflects pollen flow between different herbicide-resistant canola, presence of double herbicide-resistant off-types in seedlots, and/or agronomic practices typically employed by Canadian growers.

Effect of cooking and storage on the amount and molecular weight of(1→3)(1→4)-β-D-glucan extracted from oat products by an in vitro digestion system

Abstract: The extractability and molecular weight of β-glucan in oat bran, oat bran muffins, and oat porridge and the changes taking place during processing and storage were studied. The β-glucan was extracted using hot water and a thermostable α-amylase and by an in vitro system that simulated human digestion. Molecular weight (MW) of the extracted β-glucan was determined using high-performance size-exclusion chromatography. Hot-water treatment extracted 50–70% of total β-glucan in oat bran samples and rolled oats. The chromatographic peak MW of extracted β-glucan was in the 1.4–1.8 × 106 range. Using the in vitro digestion system, 12–33% of total β-glucan in bran and rolled oats was solubilized, and peak MW was in the same range as β-glucan extracted by hot-water treatment. In muffins, 30–85% of total β-glucan was solubilized by in vitro digestion, with a major difference in extractability among muffins from different recipes. Peak MW of extracted β-glucan was lower in all muffins when compared to origin...

Responses of the bacterial and fungal biomass in a grassland soil to multi-year applications of dairy manure slurry and fertilizer

Abstract: Plots of a tall fescue ( Festuca arundinacea ) sward in the south coastal region of BC, Canada, were treated with dairy manure slurry or fertilizer at 50 or 100 kg NH 4 -N ha −1 up to four times per year for six consecutive years; control plots received no manure or fertilizer. The length of fungal hyphae and abundance of bacterial cells were determined by direct counting at 19 sample dates during the fourth (1997), fifth (1998) and sixth (1999) application years. Bacterial abundance was significantly greater in manured soil than in fertilized and untreated soils. In contrast, hyphal length was significantly greater in untreated soil than in manured and fertilized soils. In subplots that ceased to receive manure in 1998, bacterial abundance remained greater through 1998 and 1999 than in previously fertilized plots, indicating that the 4 year cumulative effect of manure was detectable for at least two growing seasons after applications cease. The apparently negative effect of manure and fertilizer on fungal hyphae also appeared to persist through 2 years after applications ceased. Bacterial abundance increased after an initial application of manure for 1 year to previously untreated plots, but not to levels comparable to plots treated with manure continuously from 1994 to 1998. Increases in bacterial abundance, during the one to three week intervals immediately following individual applications of manure, were inconsistent and other factors, such as soil moisture, temperature and perhaps crop phenology appear to have had strong effects on the timing of these microbial responses. Annual means for bacterial abundance and total microbial biomass in the continuous manure treatment were similar for all 3 years. This suggested that the manure-induced increase in microbial biomass probably reached a plateau between one and 3 years after applications commenced. The large bacterial populations along with abundant carbon substrates in manured soil, relative to fertilized soil, were probably capable of immobilizing influxes of mineral N, explaining the observations that less leaching occured from manured than from fertilized soils.