Climate change threatens wheat yields on the Canadian Prairies; rising temperatures can shorten the critical growth period, leading to substantial yield losses. Ultra-early seeding is an emerging strategy to mitigate yield losses and increase yield stability under environmental variability. However, there is a paucity of research on the effects of ultra-early seeding on early- and late-maturing spring wheat cultivars. The objective of this study was to assess the effects of ultra-early seeding on the yield and yield stability of early- and late-maturing Canada Western Red Spring (CWRS) cultivars in Western Canada. Five early- and five late-maturing CWRS wheat cultivars were seeded at 2 °C (ultra-early) and 8 °C (conventional) soil temperatures at four Alberta, Canada locations from 2021 to 2023 and agronomic data were collected. Results indicate that ultra-early seeded late-maturing CWRS cultivars were generally higher yielding and more stable than either early-maturing cultivars or conventional seeding. Ultra-early seeding did not significantly affect yield. On the other hand, yield stability increased for nine of ten cultivars irrespective of maturity, under ultra-early seeding, indicating that this practice can reduce environmental effects on yield. Moving forward, producers should consider implementing ultra-early seeding during wet but accessible springs to increase yield stability.

Baba Canada Western Red Spring (CWRS) Wheat was developed at the University of Alberta using a modified bulk breeding method. Evaluated over 3 years (2020–2022) in the Parkland Wheat Registration Trials, Baba produced slightly higher (but not statistically significant) grain yields than Glenn, Parata, and Carberry but significantly lower than AAC Brandon. Baba matured significantly earlier than AAC Brandon, Carberry, and Glenn, but significantly later than Parata. Baba has yields comparable to Carberry but with the added advantage of earlier maturity by 2 days. Its plant height was significantly shorter than Glenn and Parata, but comparable to AAC Brandon and Carberry, with lodging tolerance within the range of the check cultivars. Although Baba had lower test and kernel weights than the checks, its grain protein content was higher than Carberry’s and similar to the other checks. Baba exhibited a good resistance to prevalent races of leaf rust, stem rust, stripe rust, and Fusarium head blight, though its response to common bunt was variable. Across 3 years of end-use quality evaluations, Baba met all requirements of the CWRS wheat market class. Notably, it showed improvements in falling number and flour yield, reinforcing its suitability for milling and baking applications. With its combination of early maturity, stable yield, good disease resistance, and desirable quality traits, Baba is a well-adapted wheat cultivar suited for cultivation in Western Canada.

Wheat ( Triticum aestivum L.) remains a major staple crop, which is vulnerable to abiotic and biotic stresses that can be compounded by climate change. This review assesses the projected effects of climate change on wheat production globally with an emphasis on the Canadian Prairies. The review aims to (i) discuss the projected impact of climate change on the Canadian prairie cropping calendar, (ii) assess the potential impacts of climate change on pest dynamics and abiotic stresses, and (iii) discuss beneficial management practices that can be employed to tackle climate change in wheat production systems. Climate change will potentially shift the current Canadian prairie calendar earlier in the year, potentially increasing wheat yields. The impact of climate change on pests is tied to the cropping calendar and the pest involved. Abiotic stresses, except carbon dioxide, will be aggravated. Beneficial management practices, that is, biostimulants, ultra-early seeding, seeding winter wheat, and cultivar mixtures, are potential strategies to stabilize wheat yield and reduce the yield gap under a changing climate. Biostimulants, although effective, have not been extensively tested for their impact on abiotic stresses in the Prairies. Studies on ultra-early warrant further research to address their effectiveness in Northern prairie regions and the challenges encountered by producers. Although growing winter wheat is an option to escape wetter spring conditions, issues with fall establishment and winter survival must be addressed. Despite the extensive global research on varietal mixtures, a knowledge gap exists regarding their benefits in the Canadian prairie context.

GWAS and targeted transcriptomic analysis identified three QTLs and novel candidate causal genes for preharvest sprouting resistance in wheat. Preharvest sprouting (PHS), which causes significant yield and quality losses in wheat, is primarily associated with low level of seed dormancy. This study conducted a genome-wide association analysis of a diverse panel of spring wheat genotypes across five environments to identify loci and candidate causal genes controlling seed dormancy/PHS resistance. Phenotypic evaluation of the mapping panel revealed substantial variation in seed dormancy levels/PHS resistance among the genotypes. Marker-trait association analysis identified 14 SNPs significantly linked to seed dormancy/PHS resistance based on a false discovery rate (FDR) of α = 0.05. These SNPs are mapped to three QTLs on chromosomes 4A, 5B, and 5D. The QTL on 4A, QPhs.umb-4A, which consists of 11 SNPs that explained 10.7 to 20.8

Eema Canada Western Red Spring (CWRS) wheat was developed at the University of Alberta using the single-seed descent breeding method. In 3 years of evaluation in the Western Bread Wheat Registration trials from 2020 to 2022, Eema produced 4.5% higher grain yield compared to the highest-yielding check, AAC Brandon, although the difference was not statistically significant. It matured 1 day later than AAC Brandon. Eema's plants were 6.5 cm shorter than Glenn, but had similar height to AAC Brandon, AAC Viewfield, and Carberry, and exhibited lodging tolerance comparable to the checks. Eema's test weight was lower, while the grain protein content was within the range of the checks. Its grain weight was higher than AAC Viewfield and similar to the other checks. Eema demonstrated strong disease resistance, being rated "Resistant" to the prevalent races of stem and stripe rusts, and common bunt, "Moderately Resistant" to leaf rust, whereas "Moderately Susceptible" to Fusarium head blight. Three years of end-use quality evaluation confirmed that Eema meets the standards for the CWRS wheat market class, with an improvement in flour yield. Overall, Eema offers a modest increase in grain yield and enhanced end-use quality compared to AAC Brandon, making it a suitable option for cultivation in the wheat-growing regions of Western Canada.

Reported global reductions in cereal grain yields due to increased global average temperature combined with increasing global populations peaking near 2050 create an immediate need to increase cereal grain yield potential and reduce the yield gap between realized on-farm grain yield and potential yield. The development of an ultra-early planting system for spring wheat (Triticum aestivum L.) on the northern Great Plains can increase the resiliency of current growing systems to a changing climate. This was achieved through the development of a unique set of practices designed to successfully shift current wheat production systems to ultra-early growing systems. Ultra-early-planted wheat-growing systems on the northern Great Plains will provide immediate benefits to the adopting producer in the form of increased grain yield and increased grain yield stability relative to current practices. As global average temperatures warm, and atmospheric CO2 concentrations increase, the northern Great Plains region is in a unique position to potentially realize grain yield increases rather than temperature-driven grain yield decreases. Shifting planting earlier and taking advantage of increased growing degree day accumulation and water use efficiencies while avoiding higher temperatures during sensitive physiological periods are tactics implemented in ultra-early growing systems that will increase in importance and relevance in the next three decades as average daily temperatures increase. A changing climate challenges the efficacy of conventional management practices to maintain wheat production.We discuss how G x E x M synergies provide the basis for the design and adoption of ultra-early planting systems.Ultra-early wheat systems harness G x E x M synergies to avoid climate-related grain yield instability.Innovations that couple with an ultra-early concept are paramount to address a potential climate crisis.Ultra-early wheat systems exemplify how a concept in applied science can provide immediate on-farm benefits.

Granular urea fertilizer applied at planting is prone to nitrogen (N) losses in certain environments. Enhanced efficiency fertilizers (EEFs) are developed to mitigate losses and optimize plant uptake. To determine the benefits of EEFs in grain yield and quality enhancement in Canada Western Red Spring (CWRS) wheat, an experiment was conducted from 2019 to 2022 at eight sites in Alberta and Saskatchewan, Canada. The effects of five N sources [urea; urea + urease inhibitor, N-( n-butyl)thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor, NBPT + dicyandiamide; and polymer-coated urea, ESN ® (Environmentally Smart Nitrogen ® )] and four N rates (60, 120, 180, and 240 kg N ha −1 ) on CWRS wheat production were examined. Results indicated that N source affected grain yield in Dark Brown Chernozem soils but not in Black Chernozem or Dark Grey Luvisol soils. In Dark Brown Chernozem soils, a dual inhibitor increased grain yield by 3.1% and 3.9% relative to urea and polymer-coated urea, respectively, while all other EEFs attained similar results. The use of a dual inhibitor EEF led to greater net returns compared to urea and polymer-coated urea in the Dark Brown Chernozem soils. Grain protein concentration increased linearly with increasing N rate from 60 to 240 kg N ha −1 . Generally, a rate of 120 kg N ha −1 was optimal for CWRS wheat grown in Canadian prairie conditions when coupled with EEFs, particularly a dual inhibitor, and grain yield and protein were often responsive.

Redcliff hard red spring wheat was developed at the University of Alberta using a modified bulk breeding method. In 3 years of evaluation in the Parkland Cooperative test from 2018 to 2020, Redcliff produced 7.3% more grain and matured 1.9 days earlier than the highest yielding check Carberry. Redcliff had 3.9 cm taller plants than Carberry but shorter than the other checks and displayed good lodging tolerance. The test weight of Redcliff was slightly higher than Carberry and Parata but lower than Glenn. The grain weight of Redcliff was higher than Parata and similar to the other checks. Grain protein content was within the range of the checks. Redcliff was rated "resistant" to the prevalent races of stem rust, "resistant" to "moderately resistant" to Fusarium head blight, "intermediate" to leaf and stripe rusts, whereas "moderately susceptible" to common bunt. Three years of end-use quality evaluation have indicated that Redcliff is acceptable for the Canada Western Red Spring wheat market class, with improvements in flour yield.

Hundreds of quantitative trait loci (QTLs) have been reported in diverse types of hexaploid wheat (Triticum aestivum L.) populations, but direct comparisons of QTLs in different studies and populations are still challenging due to the lack of physical positions for most QTLs. Here, we used the International Wheat Genome Sequencing Consortium (IWGSC) RefSeq v2.0 physical map of all markers to map QTLs associated with leaf spot (Ls), leaf rust (Lr), stripe rust (Yr), and common bunt (Cbt) resistance in two recombinant inbred line populations. QTL mapping was conducted using the IWGSC physical map of 3158 and 5732 markers and disease severity data of Peace/Carberry and Attila/CDC Go populations evaluated in three to eight environments. We uncovered a total of 82 QTLs associated with Yr (36), Ls (18), Lr (15), and Cbt (13) resistance in the individual and overall means of all combined environments. Among them, 29 were associated with all combined environments, which accounted for 0.5%-20.9% individually and 12.4%-41.2% of the total disease severity per trait. Three (QLr.dms-2D.2, QLs.dms-5B, and QYr.dms-5B.2) of the 29 QTLs were common in both populations. Fourteen out of the 29 QTLs were stable as they were identified both in the overall means and most of the individual environments. Ten chromosome arms harbored a cluster of QTLs associated with resistance to two to four diseases. This methodology would serve as one of the resources to compare QTLs identified in different populations and studies based on the improved physical information of all markers instead of population-specific and consensus linkage maps.

Fusarium head blight (FHB) is one the most globally destructive fungal diseases in wheat and other small grains, causing a reduction in grain yield by 10–70%. The present study was conducted in a panel of historical and modern Canadian spring wheat (Triticum aestivum L.) varieties and lines to identify new sources of FHB resistance and map associated quantitative trait loci (QTLs). We evaluated 249 varieties and lines for reaction to disease incidence, severity, and visual rating index (VRI) in seven environments by artificially spraying a mixture of four Fusarium graminearum isolates. A subset of 198 them were genotyped with the Wheat 90K iSelect single nucleotide polymorphisms (SNPs) array. Genome-wide association mapping performed on the overall best linear unbiased estimators (BLUE) computed from all seven environments and the International Wheat Genome Sequencing Consortium (IWGSC) RefSeq v2.0 physical map of 26,449 polymorphic SNPs out of the 90K identified sixteen FHB resistance QTLs that individually accounted for 5.7–10.2% of the phenotypic variance. The positions of two of the FHB resistance QTLs overlapped with plant height and flowering time QTLs. Four of the QTLs (QFhb.dms-3B.1, QFhb.dms-5A.5, QFhb.dms-5A.7, and QFhb.dms-6A.4) were simultaneously associated with disease incidence, severity, and VRI, which accounted for 27.0–33.2% of the total phenotypic variance in the combined environments. Three of the QTLs (QFhb.dms-2A.2, QFhb.dms-2D.2, and QFhb.dms-5B.8) were associated with both incidence and VRI and accounted for 20.5–22.1% of the total phenotypic variance. In comparison with the VRI of the checks, we identified four highly resistant and thirty-three moderately resistant lines and varieties. The new FHB sources of resistance and the physical map of the associated QTLs would provide wheat breeders valuable information towards their efforts in developing improved varieties in western Canada.

Plants exhibit differential behaviours through changes in biomass development and distribution in response to environmental cues, which may impact crops uniquely. We conducted a mesocosm experiment in pots to determine the root and shoot behavioural responses of wheat, T. aestivum. Plants were grown in homogeneous or heterogeneous and heavily or lightly fertilized soil, and alone or with a neighbour of the same or different genetic identity (cultivars: CDC Titanium, Carberry, Glenn, Go Early, and Lillian). Contrary to predictions, wheat did not alter relative reproductive effort in the presence of neighbours, more nutrients, or homogenous soil. Above and below ground, the plants' tendency to use potentially shared space exhibited high levels of plasticity. Above ground, they generally avoided shared, central aerial space when grown with neighbours. Unexpectedly, nutrient amount and distribution also impacted shoots; plants that grew in fertile or homogenous environments increased shared space use. Below ground, plants grown with related neighbours indicated no difference in neighbour avoidance. Those in homogenous soil produced relatively even roots, and plants in heterogeneous treatments produced more roots in nutrient patches. Additionally, less fertile soil resulted in pot-level decreases in root foraging precision. Our findings illustrate that explicit coordination between above- and belowground biomass in wheat may not exist.

The likelihood of success in developing modern cultivars depend on multiple factors, including the identification of suitable parents to initiate new crosses, and characterizations of genomic regions associated with target traits. The objectives of the present study were to (a) determine the best economic weights of four major wheat diseases (leaf spot, common bunt, leaf rust, and stripe rust) and grain yield for multi-trait restrictive linear phenotypic selection index (RLPSI), (b) select the top 10% cultivars and lines (hereafter referred as genotypes) with better resistance to combinations of the four diseases and acceptable grain yield as potential parents, and (c) map genomic regions associated with resistance to each disease using genome-wide association study (GWAS). A diversity panel of 196 spring wheat genotypes was evaluated for their reaction to stripe rust at eight environments, leaf rust at four environments, leaf spot at three environments, common bunt at two environments, and grain yield at five environments. The panel was genotyped with the Wheat 90K SNP array and a few KASP SNPs of which we used 23,342 markers for statistical analyses. The RLPSI analysis performed by restricting the expected genetic gain for yield displayed significant (p < 0.05) differences among the 3125 economic weights. Using the best four economic weights, a subset of 22 of the 196 genotypes were selected as potential parents with resistance to the four diseases and acceptable grain yield. GWAS identified 37 genomic regions, which included 12 for common bunt, 13 for leaf rust, 5 for stripe rust, and 7 for leaf spot. Each genomic region explained from 6.6 to 16.9% and together accounted for 39.4% of the stripe rust, 49.1% of the leaf spot, 94.0% of the leaf rust, and 97.9% of the common bunt phenotypic variance combined across all environments. Results from this study provide valuable information for wheat breeders selecting parental combinations for new crosses to develop improved germplasm with enhanced resistance to the four diseases as well as the physical positions of genomic regions that confer resistance, which facilitates direct comparisons for independent mapping studies in the future.

Both the Linear Phenotypic Selection Index (LPSI) and the Restrictive Linear Phenotypic Selection Index (RLPSI) have been widely used to select parents and progenies, but the effect of economic weights on the selection parameters (the expected genetic gain, response to selection, and the correlation between the indices and genetic merits) have not been investigated in detail. Here, we (i) assessed combinations of 2304 economic weights using four traits (maturity, plant height, grain yield and grain protein content) recorded under four organically (low nitrogen) and five conventionally (high nitrogen) managed environments, (ii) compared single-trait and multi-trait selection indices (LPSI vs. RLPSI by imposing restrictions to the expected genetic gain of either yield or grain protein content), and (iii) selected a subset of about 10% spring wheat cultivars that performed very well under organic and/or conventional management systems. The multi-trait selection indices, with and without imposing restrictions, were superior to single trait selection. However, the selection parameters differed quite a lot depending on the economic weights, which suggests the need for optimizing the weights. Twenty-two of the 196 cultivars that showed superior performance under organic and/or conventional management systems were consistently selected using all five of the selected economic weights, and at least two of the selection scenarios. The selected cultivars belonged to the Canada Western Red Spring (16 cultivars), the Canada Northern Hard Red (3), and the Canada Prairie Spring Red (3), and required 83–93 days to maturity, were 72–100 cm tall, and produced from 4.0 to 6.2 t ha−1 grain yield with 14.6–17.7% GPC. The selected cultivars would be highly useful, not only as potential trait donors for breeding under an organic management system, but also for other studies, including nitrogen use efficiency.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating disease of wheat (Triticum aestivum L.). Deployment of resistant wheat cultivars is one of the best strategies to mitigate disease-associated risks. The genotype P2711 possesses effective stripe rust resistance under field conditions in western Canada, however, the genetic basis of this resistance is unknown. To identify resistance, a recombinant inbred line (RIL) population comprised of 252 RILs was developed from the cross AAC Cameron/P2711. This population was evaluated for stripe rust severity at the adult plant stage in Creston, BC (in 2018, 2019, and 2020) and Lethbridge, AB (in 2018 and 2020), and was genotyped using the wheat 90K iSelect single nucleotide polymorphism (SNP) assay. A high-density genetic map comprised of 8,915 markers was constructed covering all the wheat chromosomes. Four resistance quantitative trait loci (QTLs) were contributed by P2711 and three from AAC Cameron. QYr.lrdc-2A.1, corresponding to the Yr17 gene, was the most stable QTL and detected in four out of five environments, whereas QYr.lrdc-2B was the second most stable QTL. These two QTL along with QYr.lrdc-5A showed a significant reduction in stripe rust severity when present together. Where most of the QTLs detected in both locations, QYr.lrdc-1A.1 and QYr.lrdc-1A.2, both were detected only in Creston, BC. Stable QTLs on chromosome 2A, 2B, and 5A, and their closely associated markers identified in this study could be utilized in marker-assisted selection for stripe rust resistant cultivar development.

KEY MESSAGE:This study performed comprehensive analyses on the predictive abilities of single-trait and two multi-trait models in three populations. Our results demonstrated the superiority of multi-traits over single-trait models across seven agronomic and four to seven disease resistance traits of different genetic architecture. The predictive ability of multi-trait and single-trait prediction models has not been investigated on diverse traits evaluated under organic and conventional management systems. Here, we compared the predictive abilities of 25% of a testing set that has not been evaluated for a single trait (ST), not evaluated for multi-traits (MT1), and evaluated for some traits but not others (MT2) in three spring wheat populations genotyped either with the wheat 90K single nucleotide polymorphisms array or DArTseq. Analyses were performed on seven agronomic traits evaluated under conventional and organic management systems, four to seven disease resistance traits, and all agronomic and disease resistance traits simultaneously. The average prediction accuracies of the ST, MT1, and MT2 models varied from 0.03 to 0.78 (mean 0.41), from 0.05 to 0.82 (mean 0.47), and from 0.05 to 0.92 (mean 0.67), respectively. The predictive ability of the MT2 model was significantly greater than the ST model in all traits and populations except common bunt with the MT1 model being intermediate between them. The MT2 model increased prediction accuracies over the ST and MT1 models in all traits by 9.0-82.4% (mean 37.3%) and 2.9-82.5% (mean 25.7%), respectively, except common bunt that showed up to 7.7% smaller accuracies in two populations. A joint analysis of all agronomic and disease resistance traits further improved accuracies within the MT1 and MT2 models on average by 21.4% and 17.4%, respectively, as compared to either the agronomic or disease resistance traits, demonstrating the high potential of the multi-traits models in improving prediction accuracies.

Marker-assisted selection requires the identification of molecular markers associated with major genes and quantitative trait loci (QTLs). In this study, we used 167 doubled haploid lines derived from two unregistered spring wheat ( Triticum aestivum L.) parental lines that belong to the Canada Western Special Purpose wheat market class to map QTLs associated with five traits using inclusive composite interval mapping (ICIM). Using ICIM, the least-squares means phenotype data across three to four environments, and a genetic map of 2676 single-nucleotide polymorphisms (SNPs) out of the wheat 90K SNP array, we identified 10 QTLs associated with days to maturity (4A and 5B), plant lodging (4B, 5A, 5D, and 7D), grain yield (2D), leaf rust (4A), and stem rust (1A and 2B). Each QTL individually explained 6.0%–22.3% of the phenotypic variance and together accounted for 8.6%–38.2% of the total variance per trait. Two of the QTLs associated with rusts ( QLr.dms-4A and QSr.dms-1A) had a minor effect (6.0%–9.0%), whereas the second QTL for stem rust ( QSr.dms-2B) had a major effect (22.3%). Although chromosome 2B harbors multiple disease resistance QTLs, the physical location of QSr.dms-2B has not been reported in previous studies. Results from this study provide additional valuable information to wheat researchers; in particular, the area on chromosome 2B should be considered for future analyses.

Previous genome-wide association studies in Canadian spring wheat ( Triticum aestivum L.) cultivars were based on consensus linkage maps of small population sizes. Here, we used a panel of 192 spring wheat cultivars widely used in western Canada to (a) explore the allelic variation and effects of six known genes and (b) identify genomic regions associated with eight agronomic traits and grain characteristics using the International Wheat Genome Sequencing Consortium (IWGSC) RefSeq v2.0 map. The panel was evaluated for heading, maturity, plant height, lodging, grain yield, grain protein content, test weight, and kernel weight under four conventionally (high N) and three organically (low N) managed environments and genotyped with the wheat 90K single-nucleotide polymorphism (SNP) array of which 23,342 SNPs were polymorphic. Using gene-specific functional markers, the proportion of homozygous genotypes with favorable alleles was low for Fhb1 (7–8%), Rht-D1 (14%), and Rht-B1 (18%); moderate for Lr34/Yr18 (28–39%); and high for Glu-A1 (78%) and Glu-D1 (85%). We identified a total of 172 SNPs located at 94 genomic regions across 19 chromosomes of which 82 regions were associated with a single trait and 12 regions coincided with two to three traits. Twenty-seven of the 94 regions (28%) were common between the conventional and organic managements systems; the remaining were management specific. Two of the identified regions on chromosome 5A (586.5–588.6 Mb) and 5B (575.8 Mb) coincided with the vernalization response Vrn-A1 and Vrn-B1 genes, respectively. The IWGSC RefSeq v2.0 physical positions presented here would serve as the basis for easily comparing independent discovery studies in the future.

Some studies have investigated the potential of genomic selection (GS) on stripe rust, leaf rust, Fusarium head blight (FHB), and leaf spot in wheat, but none of them have assessed the effect of the reaction norm model that incorporated GE interactions. In addition, the prediction accuracy on common bunt has not previously been studied. Here, we investigated within-population prediction accuracies using the baseline M1 model and two reaction norm models (M2 and M3) with three random cross-validation (CV1, CV2, and CV0) schemes. Three Canadian spring wheat populations were evaluated in up to eight field environments and genotyped with 3158, 5732, and 23,795 polymorphic markers. The M3 model that incorporated GE interactions reduced residual variance by an average of 10.2% as compared with the main effect M2 model and increased prediction accuracies on average by 2–6%. In some traits, the M3 model increased prediction accuracies up to 54% as compared with the M2 model. The average prediction accuracies of the M3 model with CV1, CV2, and CV0 schemes varied from 0.02 to 0.48, from 0.25 to 0.84, and from 0.14 to 0.87, respectively. In both CV2 and CV0 schemes, stripe rust in all three populations, common bunt and leaf rust in two populations, as well as FHB severity, FHB index, and leaf spot in one population had high to very high (0.54–0.87) prediction accuracies. This is the first comprehensive genomic selection study on five major diseases in spring wheat.

Ultra-early spring wheat ( Triticum aestivum L.) planting systems based on soil temperature on the northern Great Plains have lower overall variability in grain yield, and can increase grain yield relative to current calendar date-based spring wheat planting systems used in the region. However, ultra-early planting when soils are cold (2 °C), and resulting early crop emergence, precludes most foliar pre-seeding weed control options. Field trials were conducted at three sites in western Canada from 2017 to 2019 to evaluate the crop safety, broadleaf weed efficacy, and growing system stability resulting from the inclusion of fall applications of soil-applied residual herbicides prior to planting wheat ultra-early the following spring. Flumioxazin (protoporphyrinogen oxidase inhibitor; Weed Science Society of America (WSSA) group 14) and pyroxasulfone (very long chain fatty acid synthesis inhibitor; WSSA group 15) were applied alone and in combination at multiple rates in the late fall prior to ground freeze. The following spring, hexaploid spring wheat was planted ultra-early, based on a soil temperature trigger of 2 °C, and later, triggered by a soil temperature of 8 °C. When planting was completed ultra-early, grain yield was greater, and variability of grain yield was lower. Herbicide treatments increased broadleaf weed control, and in some environments further increased grain yield and reduced grain yield variability without resulting in phytotoxicity. The ability to safely incorporate fall-applied residual herbicides into ultra-early spring wheat planting systems provides an option for growers to adopt ultra-early planting without negatively impacting weed management on their farms.

AAC Oravena is a white-hulled spring oat (Avena sativa L.) cultivar selected and developed under organic management. AAC Oravena yields well under organic and conventional production systems, compared with check cultivars. AAC Oravena has good milling quality. AAC Oravena was registered (Reg. No. 7561) by the Variety Registration Office, Canada Food Inspection Agency, on 3 July 2014.