The success of a plant breeding program depends on many factors; one crucial factor is the selection of suitable breeding and testing locations. A test location must be discriminating so that genetic differences among genotypes can be easily observed, it must be representative of the target environments so that selected genotypes have the desired adaptation, and its representation of the target environment should also be repeatable so that genotypes selected in 1 yr will have superior performance in future years. Using the yield data of 2006 through 2010 Quebec Oat Registration and Recommendation Trials as an example, we presented a method to visualize the representativeness and repeatability of test locations based on a genotype main effect plus genotype × environment interaction (GGE) biplot. The repeatability of a test location could also be quantified by mean genetic correlations between years within the location. Based on representativeness and repeatability, four categories of test locations were classified and their usefulness in plant breeding discussed.

The presence of volunteer canola is becoming a significant agro-ecological concern, given the large-scale use of herbicide-tolerant varieties in some areas. Our goal was to estimate the frequency and persistence of volunteer canola in Québec cropping systems by surveying fields that included a single canola crop since 1995. A survey was conducted in 131 fields in the main canola-growing areas of Québec: in the Saguenay-Lac Saint-Jean region and the Québec City–La Pocatière area. Volunteer canola plants were counted in 0.25-m2 quadrats every 10 m along a W pattern, and every 15 m along the margins of 88 fields. Volunteer canola plants were found in 90% of the fields surveyed and in a wide range of crops, including cereal, corn, and soybean. Average densities of 4.9 and 3.9 plants/m2 were found 1 yr after canola production in fields and field margins, respectively. Volunteer canola densities decreased significantly over time. However, volunteer plants were still present at low densities 4 and 5 yr after production. Dense stands of volunteer canola were found before postemergence herbicide application in no-till fields (9.8 ± 4.1 plants/m2), suggesting that, contrary to what was suggested in the literature, seeds could become dormant in no-till as well as in tilled systems. A small proportion of the volunteer canola plants observed in no-till fields near Québec City and Ottawa included plants that had overwintered, either originating from fall-germinated seedlings, harvested adult plants that had grown new leaves before the onset of winter, or spring regrowth from the base of unharvested adult plants from experimental plots. The presence and persistence of low densities of volunteer canola may not have been a cause of concern until now. However, producers should be made more aware of the potential short-and long-term problems associated with potential gene flow between different herbicide-tolerant canola (HT canola) varieties and also between HT canola and related weed species.

Total nonstructural carbohydrates (TNC) provide readily fermentable energy to rumen microbes and their increased concentration in forages improves N use efficiency in dairy cows (Bos taurus). This study was conducted to compare TNC concentration of grass and legume forage species and to determine how variations of TNC concentration caused by time of cutting during the day differ among forage species and how these variations are related to other attributes of forage nutritive value. Six grass and two legume species were cut at 0900 h (AM) and 1530 h (PM) in the spring growth and summer regrowth of two harvest years. The TNC concentration was estimated by the sum of sucrose, glucose, fructose, pinitol, fructans, and starch. Red clover (Trifolium pratense L.) and tall fescue [Schedonorus phoenix (Scop.) Holub] had the greatest TNC concentration [94.2 g kg−1 of dry matter (DM) across time of cutting and growth periods] whereas reed canarygrass (Phalaris arundinacea L.) had the lowest TNC concentration (65.5 g kg−1 DM). Concentration of TNC of all species increased with PM cutting but the extent of this increase varied among forage species. This increase, averaged across growth periods, went from 13% in smooth bromegrass (Bromus inermis Leyss; 67.0–73.9 g kg−1 DM) to 68% in reed canarygrass (49.6–81.4 g kg−1 DM). Increased TNC concentration with PM‐cutting resulted in significant but small decreases in N, acid detergent fiber (ADF), and neutral detergent fiber (aNDF) concentrations and a small increase in in vitro true digestibility (IVTD). Both species selection and PM cutting can be used to increase forage total nonstructural carbohydrates (TNC) concentrations.

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