The evolution and spread of herbicide-resistant weeds threatens long-term sustainability of Canadian agro-ecosystems. Herbicide-resistant weeds increase management inputs and costs, increase off-target and environmental exposure to pesticides, reduce yield quality and quantity, and impede harvest efficiency. Amaranthus species including Palmer amaranth (Amaranthus palmeri S. Wats.) and waterhemp (Amaranthus tuberculatus (Moq.) J.D. Sauer) are particularly concerning due to both their propensity towards herbicide resistance evolution, their history of invasion, and their spread in agro-ecosystems. A biovigilance approach is taken to build awareness of these pigweeds' initial invasion and spread in the USA. Characteristics of their identification, potential hybridization, and known herbicide resistance evolution are reviewed. Fourteen species of Amaranthus are found in Canada, nine of which (including waterhemp) possess herbicide-resistant biotypes. A total of 45 hybrids between various Canadian Amaranthus species with each other or Palmer amaranth have been noted. Hybrids have been experimentally produced or observed from herbarium specimens, with three cases of herbicide resistance transfer notably with Palmer amaranth or waterhemp. Mitigation strategies will depend on successful species identification and herbicide resistance status determination. Common pathways for Palmer amaranth introductions in the northern USA include both animal feed systems with grain screenings and crop production systems including seed and equipment contamination. Regional awareness campaigns will be critical to support Canadian farmers in identifying and quickly mitigating invasions of Palmer amaranth and waterhemp to prevent establishment and spread of infestations into new areas.

Multiple herbicide-resistant kochia (Bassia scoparia (L.) A.J. Scott) has grown in prevalence in the canola (Brassica napus L.) production region of North America. Glufosinate-resistant canola facilitates kochia management since glufosinate-resistant kochia is not known to occur. Field experiments were conducted from 2013 to 2015 in five environments near Lethbridge and Coalhurst, Alberta, to identify herbicide strategies targeting acetolactate synthase inhibitor-resistant kochia with and without glyphosate resistance in glufosinate-resistant canola. Sequential glufosinate treatments (500 g ai ha⁻¹) postemergence (POST) caused excellent (≥90%) kochia control and biomass reduction across environments. Preplant (PP) carfentrazone + sulfentrazone (9 + 105 g ai ha⁻¹) alone or followed by (fb) POST glufosinate (9 + 27 fb 500 or 9 + 105 fb 500 g ai ha⁻¹) resulted in excellent kochia control in all environments tested. PP carfentrazone + sulfentrazone (9 + 53 g ai ha⁻¹) alone, and a single POST treatment with glufosinate (500 or 590 g ai ha⁻¹) alone or preceded by fall-applied ethalfluralin (1100 fb 500 g ai ha⁻¹) with or without PP carfentrazone (1100 fb 9 fb 500 g ai ha⁻¹) caused ≥80% kochia control and biomass reduction in all environments tested. However, treatments containing PP carfentrazone + sulfentrazone caused unacceptable canola injury or yield loss in at least one environment. In conclusion, single or sequential treatments of glufosinate POST managed multiple herbicide-resistant kochia effectively in canola. Layering fall-applied/PP ethalfluralin and/or PP carfentrazone with glufosinate POST may help alleviate resistance selection pressure placed on glufosinate in canola.

Consensus around the optimal direction of roller crimping a row-planted cover crop has not been established. Several publications report crimping either parallel or perpendicular to the direction of cover crop planting with little to no justification apart from unpublished observations or hypotheses. This study explicitly compared the effects of roller crimping direction on crimping efficacy, weed suppression, and cash crop yield. At Elora, ON in 2020 and 2021, and Harrow, ON in 2021, a cereal rye (Secale cereale L.) cover crop was planted in three orientations (north-south vs. east-west vs. no rye control) then terminated with a roller crimper parallel or perpendicular to the direction of planting. A sweet corn (Zea mays L.) cash crop was planted either north–south or east–west in the same direction as roller crimping. A split plot treatment of weediness (weedy vs. weed-free) was applied. It was found that roller crimping direction did not have a consistent effect on rye mortality or number of upright tillers, nor did it affect weed control. However, total marketable sweet corn fresh weight decreased in perpendicular crimped rye compared to parallel crimping, despite equivalent cob counts. We did not find evidence in this study to suggest that perpendicular roller crimping improves ground cover and therefore weed suppression, contrary to other unpublished observations. Given the effect on sweet corn yield, roller crimping perpendicular to the direction of cover crop planting may not be a suitable practice. Alternative methods for improving cover crop-based weed control should be investigated.

Significant increase in wintertime air temperature, especially the reduced cold extremes under climate change, might be beneficial to the winter survival of perennial crops. However, climate warming could result in less snowfall, reduced snow cover, as well as changes in climate conditions for fall hardening and winter thaws. How these changes might impact the risks of winter damages to overwintering crops, such as perennial forage crops requires a comprehensive assessment for proactively adapting to climate change in the agricultural sector, especially the beef and dairy industries. Based on the most up-to-date climate projections from a set of global climate models, we used a snow model and a suite of agroclimatic indices for perennial forage crops to assess potential changes in the risks of winter injury to perennial forage crops across Canada in the near-term (2030s), the mid-term (2050s), and the distant future (2070s). Our results show that the risk of exposure to extremely low temperatures (daily T_min ≤ −15 °C) without snow protection is projected to decrease across Canada with improved conditions for fall hardening. However, winter thaws and rainfall are projected to increase, and this would increase the risk of winter injury due to loss of hardiness together with potential soil heaving and ice encasement.

Winter survival is an essential trait for winter wheat (Triticum aestivum L.) cultivars grown in high latitude regions such as Eastern Canada. Indoor studies have identified that copy number variation of genes influencing freezing is an essential component. Although Canadian winter wheat is predominantly grown in Eastern Canada, the extent to which allele variation in freezing tolerance genes affects winter survival in this region remains unknown, as there are presently no studies characterizing such variation in Canadian winter wheat germplasm. In this study, we characterized a panel 415 Canadian winter wheat cultivars for haplotype diversity of the Frost Resistance-2 (Fr-A2) locus and copy number variation of Vernalization-A1 (Vrn-A1) and C-repeat binding factors-A14 (CBF-A14). Additionally, this study evaluates each gene’s effect on winter survival across two locations and 2 years. We found that a combination of Vrn-A1 copy number and Fr-A2 haplotype accounted for 67.38% of the genotypic variance. Most of the cultivars tested (77.3%) carry the allele combination of three copies of Vrn-A1 and the Fr-A2-T haplotype, which was associated with the best winter survival. Interestingly, copy number of Vrn-A1 did not significantly affect heading time, therefore, selecting for higher copy number of Vrn-A1 would not affect maturity.

Fodder Galega (Galega orientalis Lam.) is a perennial legume adapted to the temperate regions of the world. The objective of this research was to compare the performance of fodder Galega to alfalfa (Medicago sativa L.), sainfoin (Onobrychis viciifolia Scop.), and cicer milkvetch (Astragalus cicer L.) in monocultures and grass–legume mixtures. From 2018 to 2020, a multiple-location trial was conducted at Swift Current, Saskatoon, Melfort, SK and Beaverlodge, AB, Canada. The average forage mass of fodder Galega in monoculture was 3226, 1176, and 1678 kg·ha^–1 at Melfort, Saskatoon, and Swift Current, respectively, and was lower than alfalfa. However, fodder Galega and alfalfa had similar forage mass at Beaverlodge (7900 and 7670 kg·ha⁻¹, respectively). The proportion of fodder Galega in the grass–legume mixtures was 36%–42% in 2019, decreasing to 3%–27% at Saskatoon. At Swift Current, fodder Galega in the mixtures was 11%–13% in 2019, which almost disappeared from the stand in 2020. At Beaverlodge, fodder Galega maintained 38%–47% in 2019 and increased to 47%–69% in 2020. Fodder Galega had similar acid detergent fiber to cicer milkvetch at two of four sites, which was lower than those of alfalfa and sainfoin. The crude protein of fodder Galega and its mixtures with grasses was lower than other mixtures at the three Saskatchewan sites, but was higher at Beaverlodge. Our results indicate that fodder Galega has potential to be utilized as a forage legume in cooler northern regions, but its productivity was low in the Dark Brown and Brown soil.

Fusarium head blight (FHB) is one of the most significant diseases affecting wheat and other small-grain cereals worldwide. Developing FHB-resistant cultivars is critical but requires field and greenhouse disease assessment, which are typically laborious and time consuming. In this work, we developed automated applications based on three-dimensional (3D) convolutional neural networks (CNNs) that detect FHB symptoms expressed in wheat, estimate the total number of spikelets versus the total number of infected spikelets on a wheat head, and subsequently calculate FHB severity index. Such tools are an important step toward the creation of automated and efficient phenotyping methods. The data used to generate the results are 3D point clouds consisting of four colour channels—red, green, blue (RGB), and near-infrared (NIR)—collected using a multispectral 3D scanner. Our 3D CNN models for FHB detection achieved 100% accuracy. The influence of the multispectral information on performance was evaluated; the results showed the dominance of the RGB channels over both the NIR (720 nm peak wavelength) and the NIR plus RGB channels combined. Our best 3D CNN models for estimation of total and infected number of spikelets achieved mean absolute errors (MAEs) of 1.13 and 1.56, respectively. Our best 3D CNN models for FHB severity estimation achieved 8.6 MAE. A linear regression analysis between the visual FHB severity assessment and the FHB severity predicted by our 3D CNN showed a significant correlation.

Cold and excess moisture pose a serious threat to soybean production especially during seed germination in short-season environments. In this study, the effects of low temperature and excess moisture stress on seed germination were investigated in 187 soybean accessions originating from 18 countries. The experiment used a combination of three temperature conditions (i.e., 20 °C/14 °C, 14 °C/10 °C, and 10 °C/10 °C day/night) and two moisture levels (i.e., normal and excess). The seed germinability traits measured included germination rate (GR), germination index, germination time, germination uniformity, and coefficient of velocity of germination. Overall, GR was lowest in the 20 °C/14 °C + excess moisture and germination time was longest in the 10 °C/10 °C + excess moisture. When compared with 20 °C/14 °C + normal moisture treatment, GR at 10 °C/10 °C + excess moisture decreased by 38%; germination time increased by 20 days; seed viability decreased by 83%; germination uniformity decreased by 70%; germination speed decreased by 73%. Differences in GR, germination index, and germination velocity under different treatments were affected by temperature, moisture, and their interaction. Variation in germination time uniformity was determined by temperature, with no significant effects of moisture conditions and the interaction of temperature and moisture. It was shown that the temperature–excess moisture interaction led to a sharp decrease in seed germination. Two genotypes including PI 603147 and PI 507702 were identified with a GR over 90% at 10 °C/10 °C + excess moisture. This study generated new knowledge and data to further the understanding of genetic resistance to cold and excess moisture stress in soybean.

Barley is a major grain crop in Canada and is used for generating malt, in addition to being used as human food and animal feed. Differentiating barley varieties is important for malt quality assurance and grain handling. Here, we present a DNA-based testing method for the identification of Canadian barley varieties. The method uses 24 custom TaqMan genotyping assays, which are analyzed using the high-throughput SmartChip system (Takara Bio Inc.). Using this method, we are able to distinguish 124 barley varieties commonly grown in Canada.