The oat (Avena sativa L.) breeding program at the Eastern Cereal and Oilseed Research Centre of Agriculture & Agri‐Food Canada has the responsibility to breed new oat cultivars for producers in eastern Canada, which includes Ontario, Quebec, and the Atlantic provinces. A 3‐yr multilocation test was conducted to understand the genotype × location interaction patterns and the relationships among test locations in eastern Canada. A genotype + genotype × environment interaction biplot analysis of yield data revealed three distinct oat mega‐environments in eastern Canada: (i) northern Ontario, (ii) southern and eastern Ontario, and (iii) Quebec and Atlantic Canada. To breed for all mega‐environments, initial yield screening must be conducted at locations representing each of these mega‐environments. Based on the relationships among test locations, six essential test locations were identified: three in Ontario, two in Quebec, and one in Atlantic Canada. Testing at all six locations appeared to provide a good coverage of the whole oat‐growing area in eastern Canada. Based on these findings, a breeding and test strategy was developed. This includes conducting initial yield screening at three locations in Ontario, Quebec, and Atlantic Canada, followed by a formal yield test at all six essential test locations. Specifically adapted genotypes selected from this test will then be tested in the Registration Tests in their respectively adapted subregions.

In western Canada, more money is spent on wild oat herbicides than on any other weed species, and wild oat resistance to herbicides is the most widespread resistance issue. A direct-seeded field experiment was conducted from 2010 to 2014 at eight Canadian sites to determine crop life cycle, crop species, crop seeding rate, crop usage, and herbicide rate combination effects on wild oat management and canola yield. Combining 2× seeding rates of early-cut barley silage with 2× seeding rates of winter cereals and excluding wild oat herbicides for 3 of 5 yr (2011 to 2013) often led to similar wild oat density, aboveground wild oat biomass, wild oat seed density in the soil, and canola yield as a repeated canola–wheat rotation under a full wild oat herbicide rate regime. Wild oat was similarly well managed after 3 yr of perennial alfalfa without wild oat herbicides. Forgoing wild oat herbicides in only 2 of 5 yr from exclusively summer annual crop rotations resulted in higher wild oat density, biomass, and seed banks. Management systems that effectively combine diverse and optimal cultural practices against weeds, and limit herbicide use, reduce selection pressure for weed resistance to herbicides and prolong the utility of threatened herbicide tools.

Forages with increased total nonstructural carbohydrate (TNC) concentrations improve the N-use effi ciency of dairy cows. Th is study determined the eff ect of time of cutting (0700 vs. 1500 h), stage of development (heading and anthesis), and N fertilization (30, 50, 70, 90, and 110 kg N ha −1 as NH 4 NO 3 ) on the fermentable carbohydrate concentration of timothy (Phleum pratense L.) grown in northern Ontario, Canada. Forage dry matter (DM) yield and concentrations of N, starch, sucrose, glucose, fructose, and fructans were determined. Concentration of soluble carbohydrates (SC) was estimated by the sum of sucrose, glucose, and fructose, while TNC was obtained by adding SC and starch. Nitrogen fertilization did not aff ect forage carbohydrate concentrations, but slightly increased DM yield. Forage had higher TNC, starch, sucrose, and fructose concentrations (+9 to 63%) but lower glucose concentration (-27%) when harvested at anthesis compared with heading. Concentration of high degree of polymerization (HDP) fructans was close to 0 at heading and increased to 64.3 mg g −1 DM at anthesis. Th e aft ernoon-cut forage had higher TNC (+53%), SC (+60%), and sucrose (+87%) concentrations than the morning-cut forage; this positive eff ect was greater when timothy was harvested at heading compared with anthesis. Starch and HDP fructan concentrations were similar for both times of cutting, whereas results for glucose and fructose were inconsistent. Delayed cutting during the day and an extended growth period increased timothy TNC and HDP fructan concentrations to an extent likely to improve the N use effi ciency of dairy cows.

The effect of five harvesting times on the incidence of seed-borne Fusarium spp. was examined using three spring wheat cultivars grown at two locations in eastern Ontario in 1999 and 2000. Twelve Fusarium spp. were isolated from 3831 of the 24 000 seeds, which were surface disinfected and plated onto modified potato dextrose agar. Fusarium sporotrichioides Sherb., F. graminearum Schwabe, F. poae (Peck) Wollenw., F. equiseti (Corda) Sacc., and F. avenaceum (Fr.) Sacc. were the most frequently isolated species and were isolated from 6.8, 3.7, 2.8, 1.8, and 0.6% of total seeds, respectively. The remaining species, F. acuminatum Ellis & Everh., F. crookwellense Burgess, Nelson & Toussoun, F. culmorum (W.G. Sm.) Sacc., F. oxysporum Schlecht., F. sambucinum Fuckel, F. solani (Mart.) Sacc., and F. tricinctum (Corda) Sacc., collectively infected only 0.3% of total seeds. The incidence of F. graminearum, F. sporotrichioides, and total Fusarium spp. increased about twofold, from 1.7, 3.9, and 9.5% in seed harvested very early to 5.5, 8.7 , and 19.8%, respectively, after delayed harvest. Also, F. poae had a significantly lower incidence at very early and early harvest times compared to normal or later harvest dates. Incidence of total other Fusarium spp., percentage of fusarium damaged kernels (FDK), and deoxynivalenol (DON) concentration were relatively low in the harvested grain and not affected by harvesting time. Of the three cultivars used, AC Barrie had the lowest incidence of Fusarium spp., FDK, and DON concentration in the grain; Quantum was intermediate; and Celtic had the highest. Variations in the incidence of Fusarium spp. for location and year were observed and likely related to levels of inoculum and weather conditions before and during harvesting times. Key words: Wheat, grain quality, farinograph, protein concentration, N management, cultivar selection and marketing