Bread wheat (Triticum aestivum L.) is an important crop and export commodity for Canada. Increased global population, demand for superior quality grains, and rapidly evolving pathogens have necessitated the breeding of high-yielding, disease-resistant wheat cultivars. Significant improvements in breeding efficiency can be made through advances in wheat genetics and genomics to develop tools that accelerate genetic gains in wheat. The identification of genes and quantitative trait loci for economically important traits and the development of associated molecular markers have the potential to improve selection efficiency. Marker-assisted selection enriches desirable allelic frequency, complements phenotypic data, and facilitates gene stacking. Molecular markers have been developed for various genes and quantitative trait loci conferring resistance to leaf rust, stripe rust, stem rust, Fusarium head blight, loose smut, common bunt, leaf spot, wheat blossom midge, and wheat stem sawfly. Markers are available for wheat grain and flour characteristics as well. Agronomic traits such as vernalization requirement, day-length sensitivity, and plant height can also be selected using molecular markers. Validated single nucleotide polymorphism based markers are a useful tool in breeding new wheat varieties for the Canadian prairies. In the current review, we present a compilation of validated molecular markers that are polymorphic and potentially useful for Canadian wheat breeding.

Soybean (Glycine max) acreage on the Canadian Prairies has increased rapidly in recent years. Production has expanded into semiarid regions where irrigation and drainage problems often result in the accumulation of salts in the soil. Fusarium avenaceum and Rhizoctonia solani are the two dominant pathogens in the disease complex that cause root rot and seedling blight of legume crops on the Canadian Prairies. The effects of F. avenaceum or R. solani in combination with soil salinity on soybean root rot were evaluated under greenhouse and mini-plot conditions. As expected, inoculation with F. avenaceum or R. solani consistently reduced seedling emergence and increased root rot severity in soybean. At high soil electrical conductivity values and inoculum densities, seedling emergence decreased and root rot severity increased in soybean in both trials with F. avenaceum and R. solani. Twenty short-season soybean cultivars that were well suited for production in Alberta were evaluated for their reactions to inoculation with F. avenaceum or R. solani in a saline soil (21.1 dS m^-1). High seedling emergence was observed for cultivars 900Y61, P002T04R, 900Y01, TH27005RR, P001T34R, and 900Y81 in the non-inoculated control, for P002T04R and 900Y61 in the F. avenaceum treatment, and for 900Y61, 900Y81, and 900Y71 in the R. solani treatment. Root rot severity was low for cultivars NSC Portage and 900Y61 in the non-inoculated control and P002T004R in the F. avenaceum treatment. The cultivar 900Y61 also consistently had lower disease severity over the trials in the mini-plot test.

Mutations are the key drivers for evolution and diversification in plants. In varietal selection, sources for variation are always sought as starting breeding materials. Thus, in the absence of desired natural variations in breeding populations, targeted or random mutagenesis is applied to induce variations. Cultivated potato (Solanum tuberosum L.) is autotetraploid crop species with a narrow and highly heterozygous genetic base, and the complexity of its genome makes its genetic studies more difficult. In the current study, induced mutagenesis was performed in diploid potato using ethyl methane sulfonate (EMS) to enlarge the genetic variability for its use as pre-breeding materials in both polyploid and diploid potato breeding. As starting materials, true potato seeds were treated with 1.2% EMS for 4–6 h along with untreated seeds as controls. A large variation in terms of germination rate, plant, flower, and tuber phenotype was observed in EMS-treated plants compared with their untreated counterparts. In particular, abnormal phenotypes including twisted stem, partial and (or) completely chlorotic leaves and stems, variations in stem colour and weak-stemmed plants with lateral growth habit as well as plants with determinate growth habit were observed along with normal plant characteristics. Moreover, variations in flower colour and tuber colour, shape, and size, as well as yield potential, were observed in EMS-treated lines. The reported phenotypic characterization of EMS mutagenized diploid potato collection is to our knowledge the first in its kind and represents a premium genetic resource for potato breeding programs and plant biologists for genes functional characterization in potato.

Annual grasses are difficult to control in sweet corn in Canada due to the scarcity of registered herbicides with grass activity. In addition to the potential soil health benefits, over-seeding living mulches into the cropping system may help sweet corn growers improve annual grass control by increasing competitive ground cover. To test this hypothesis, trials were established at three locations in Ontario and Quebec, Canada, in 2008 and 2009. At each location, sweet corn was over-seeded at the 4–6 leaf stage with one of three living mulches alone or in combination with an herbicide. The living mulch/herbicide pairings were adzuki bean (linuron + S-metolachlor), cereal rye (saflufenacil), and oilseed radish (pendimethalin). All living mulch treatments were compared with an untreated control and an industry standard (S-metolachlor/atrazine). When sweet corn was over-seeded with living mulches alone, the most effective annual grass control was provided by the cereal rye. The least effective living mulch was adzuki bean, but the combination of adzuki bean plus a herbicide was the most effective for annual grass suppression. The final marketable yields in all living mulch treatments were always lower than the industry standard. In spite of effective annual grass control, reduced yields may make the adoption of the tested living mulch species less attractive to conventional sweet corn growers.

The objectives of this study were to identify traits and screen genotypes sensitive to narrow-waveband light-emitting diode light in 18 vegetable genotypes. Their phenotypic plasticity responses were examined under a combination of red (85%) and blue (15%) light-emitting diodes relative to darkness from seed germination to cotyledon unfolding. The photosynthetic photon flux density was around 316 μmol m^-2 s^-1 and the photoperiod was 17 h. Generally, light vs. dark delayed germination by reducing germination rate and increasing spread time of germination; inhibited shoot growth by reducing shoot length and fresh mass; promoted root growth by increasing root length, diameter, branching, and fresh mass; and promoted genotype-inherent colouring in leaves and stems. Shoot colour, shoot length, and (or) root branching showed higher plasticity indices than other plant traits in response to light, suggesting that some or all of these plant traits are more sensitive to lighting across the tested genotypes. Using cluster analysis based on the plasticity index, the 18 genotypes were separated into six groups that expressed response sensitivity to part or all of the above-mentioned traits. Based on the average plasticity index of all the tested plant traits, the 18 genotypes were graded into four groups using the Fisher optimal partition. Small- vs. large-seed species and the red- vs. green-leaf/root cultivars within the same species showed higher phenotypic plasticity indices in most cases, suggesting that they are more sensitive to lighting.

WRKY transcription factors are widely involved in abiotic stress responses in plants. However, their roles in the abiotic stresses of Malus plants are still not well known. In this study, a WRKY gene is isolated from Malus baccata (L.) Borkh. and designated as MbWRKY5. MbWRKY5 contains two WRKY domains and one Cys₂-His₂ (C₂H₂) zinc-finger motif, and was localized in the nucleus. The expression levels of MbWRKY5 were up-regulated by salinity, heat, cold, drought, and abscisic acid treatments in M. baccata seedlings. When MbWRKY5 was introduced into tobacco, an improvement in tolerance to drought and salt was achieved in transgenic plants. Under drought and salt treatments, transgenic plants had higher contents of chlorophyll, proline, glutathione, and ascorbate, and increased activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) than wild-type (WT) tobaccos. Compared with WT plants, overexpression of MbWRKY5 in transgenic tobacco also led to decreased levels of malondialdehyde and hydrogen peroxide (H₂O₂) under drought and salt stresses. Moreover, the MbWRKY5-OE tobaccos increased the expression levels of stress-related genes involved in oxidative stress response (NtPOD, NtSOD and NtCAT) and membrane protection (NtLEA5, NtERD10D, and NtP5CS), especially under drought and salt stresses. These results suggest that the MbWRKY5 gene plays a positive regulatory role in drought and salt stress responses.

Field pea (Pisum sativum) is an important economic and rotational crop in Alberta, Canada; however, standability problems are a major barrier to increasing seeded area in highly productive growing environments. Field experiments were conducted from 2015 to 2017 at three sites in the central and Peace regions of Alberta to determine if (i) pea standability and production can be improved using inter-row seeding into untilled standing wheat stubble; (ii) pea standability and production can be improved using chlormequat chloride (CCC), trinexapac-ethyl (TXP), or ethephon (ETH) plant growth regulators (PGRs); and (iii) PGR responses are cultivar-specific. Depending on the site–year, there were 16–17 inter-row seeding, PGR, and cultivar treatment combinations arranged in a randomized complete block design. Relative to the no-stubble control, inter-row seeding into 20- or 30-cm-tall, untilled wheat stubble significantly improved standability between 6% and 23% under conditions when lodging occurred. It also reduced days to maturity and increased 1000-seed weight, but had no effect on yield. Individual PGR treatments (CCC, TXP, and ETH) generally had small and inconsistent impacts on agronomic traits, yield, and seed quality. In dry conditions, PGRs reduced yield. CDC Meadow was slightly more responsive to PGR treatments than AAC Lacombe, indicating responses may be cultivar-specific. Because of the small and inconsistent responses, PGRs have little value as an agronomic tool in field pea. Alternatively, inter-row seeding into standing wheat stubble is a low-cost, easy to implement practice for improving field pea standability.

The physiological and anatomical impact of field dodder (Cuscuta campestris Yunck.) on alfalfa and sugar beet was examined under controlled conditions. The following parameters were checked: physiological — content of pigments (chlorophyll a, chlorophyll b, and carotenoids) and mineral nutrients: nitrogen, phosphorus, potassium, and percent of organic and mineral nutrients; and anatomical — thickness of the epidermis and cortex, diameter of the stem and central cylinder of alfalfa plants, diameter of tracheids and phloem cells, area of xylem and phloem, and hydraulic conductance of petiole bundles in petiole vascular bundles of sugar beet plants. Leaf parameters were also measured on both host plants: thickness of upper and underside leaf epidermis, thickness of palisade, spongy and mesophyll tissue, and diameter of vascular bundle cells. Pigments content and anatomical parameters were measured 7, 14, 21, 28, 35, and 42 d after infestation (DAI), while mineral nutrient contents were determined 20 and 40 DAI. Field dodder caused a significant reduction in pigments content in infested alfalfa (15%–68%) and sugar beet plants (1%–54%). The results obtained in this study confirmed that this parasitic flowering plant has a strong effect on most anatomical parameters of the stem and leaf of alfalfa and leaf and petiole of sugar beet. Also, it was revealed that field dodder increased the contents of N, P₂O₅, K₂O, and organic nutrients in infested alfalfa plants, while infested sugar beet plants had higher contents of N and organic nutrients compared with non-infested plants.

MADS-box proteins are important transcription factors that play essential roles in various aspects of plant development, particularly in flower development. In this study, we performed the identification and functional characterization of CsMADS09 isolated from cucumber (Cucumis sativus L.). CsMADS09 contains a 648-bp open reading frame encoding 215 amino acid residues, and shares high sequence identities with the members of the AP1/FUL family of MADS-box proteins, especially the euAPETALA1 (euAP1) subclade. Many cis-elements related to plant development, stress response, and hormones were identified in the promoter region of CsMADS09. Quantitative real-time polymerase chain reaction results showed that CsMADS09 was mainly expressed in reproductive tissues such as male flowers and unexpanded ovaries, while its expression was low in roots and only traceable in fertilized ovaries. Moreover, the results revealed that CsMADS09 expression tended to decline during male flower development and stayed nearly constant during female flower development. Ectopic expression of CsMADS09 resulted in earlier flowering and abnormal leaf development in transgenic Arabidopsis. This study is the first functional analysis of an AP1-like gene from cucumber and provides some clues for revealing the molecular mechanisms of flower development in cucumber.

The objective of this project was to determine the optimal sowing dates and densities for winter wheat to increase winter survival and yield under Quebec growing conditions. The trials were carried out from 2014 to 2016 at four sites, representing three cereal production zones (zones 1, 2, and 3). Three cultivars were assessed using four sowing dates and four seeding densities (250, 350, 450, and 550 seeds m^-2). In the first year, the wheat at two of the four sites survived (82%–100%), and in the second year, all the sites showed good survival rates (69%–99%). In zone 2, winter survival was higher for the early sowing dates compared with later dates. Sowing date and seeding density had no effect on survival in zones 1 and 3. Maximum yields were attained with sowing dates from mid- to late September in zone 1; from early to mid-September in zone 2; and from mid-August to mid-September in zone 3. An increase in seeding density from 250 to 550 seeds m^-2 led to an average yield gain of 9% in zones 2 and 3, but no gain in zone 1. Winter survival rates and yield differ between cultivars.

Auxin plays an important role in various aspects of plant growth and development. Auxin response factors (ARFs) are plant-specific transcription factors that regulate the expression of auxin-responsive genes by binding with auxin response elements (AuxinREs) in the promoter region of such genes. In this study, a genome-wide analysis of the ARF genes in Prunus persica was carried out using the latest updated genomics data of this plant. A total of 17 ARF genes were identified and were named PpARF1 to PpARF17. A comprehensive overview of these PpARFs was undertaken, including a phylogenetic analysis and analysis of gene structures, conserved motifs and domains, chromosome location, cis-elements in the promoter region, and gene expression patterns. The 17 PpARF genes were distributed over eight chromosomes. All identified PpARF proteins had an ARF domain and a typical B3-DNA-binding domain that consisted of two α-helixes and seven β-sheets. Some of the PpARF proteins also had an Aux/IAA domain. Phylogenetic analysis categorized PpARF proteins into four groups. PpARF genes had many elements related to stress responses in the promotor region and showed distinct expression levels in leaves and roots. The present study provides basic information about the ARF gene family in Prunus persica and enables further verification of candidate genes related to plant growth.

Ascochyta blight of pea is an important disease that can cause severe yield loss. Our previous studies identified several closely linked single nucleotide polymorphism (SNP) markers associated with ascochyta blight resistance. The objective of this study was to validate SNP markers in 36 cultivars from the Saskatchewan pea regional variety trial. Ascochyta blight scores ranged from 1.0 to 9.0 at the physiological maturity stage under field conditions across the 25 site–years in Saskatchewan from 2013 to 2017. Based on Kompetitive Allele-Specific PCR assays, six SNP markers were used for an association study. SNP markers RGA-G3Ap103, PsC8780p118, and PsC22609p103 were significantly (P < 0.05) associated with ascochyta blight scores in 2013 and 2016 at Saskatoon. PsC8780p118 was significantly associated with ascochyta blight scores at Milden in 2014 and Rosthern in 2017. Furthermore, RGA-G3Ap103 showed significant association at Milden in 2014. Based on association studies, RGA-G3Ap103 and PsC8780p118 may have some potential as markers for pea breeding.

The receptor for activated C kinase 1 (RACK1) belongs to a protein subfamily that contains a tryptophan-aspartic acid-domain (WD) repeat structure. In this study, a soybean RACK1 gene (GmRACK1) was cloned. The amino acid sequence of GmRACK1 had seven WD repeats, which contained typical glycine-histidine (GH) and WD dipeptides. Tissue-specific expression showed that GmRACK1 is expressed at differential levels in all examined tissues and strongly down-regulatd by abscisic acid (ABA) and abiotic stress. Subcellular localization suggested that GmRACK1 is located in the plasma membrane, cytoplasm, and nucleus. In response to drought and salt stress, the GmRACK1-RNAi lines showed significantly higher dry weight of whole plants, chlorophyll content, and survival rate of soybean seedlings than wild-type and homozygous (OE) lines. GmRACK1-RNAi plants were observed to be more sensitive to ABA-mediated seed germination and root growth. Furthermore, we found that the level of ABA and transcript levels of stress-responsive genes were clearly up-regulated under drought and salt stress conditions in GmRACK1-RNAi plants. Consistent with the accumulation of reactive oxygen species (ROS), elevated electrolyte leakage and malondialdehyde, and lower expression of ROS-scavenging genes were found in the GmRACK1-OE lines. The GmRACK RNAi lines exhibited increased tolerance to drought and salt stress compared with the wild-type and OE lines. In addition, yeast two-hybrid assays showed that GmRACK1 could interact with WNK8, eIF6, and RbohC-N. These results therefore indicate that GmRACK1 responds to drought and salt stress through ABA signaling and the regulation of cellular ROS production in plants.

Adequate supply of plant nutrients is crucial for haskap plant growth and increased productivity. A study was carried out to determine the variability in haskap (Lonicera caerulea L. cv. Indigo Gem) plant characteristics in relation to soil and leaf tissue nutrient status. A total of 19 composite soil samples and corresponding plant leaf tissue samples were collected in 2016 from 12 locations in Nova Scotia. Plant parameters measured include growth rate, leaf size, leaf chlorophyll content, and visual observations. A boundary-line approach was used to determine nutrient sufficiency ranges in leaf tissues of 2.23%–2.96% for N, 0.22%–0.28% for P, 0.84%–1.32% for K, 1.63%–2.10% for Ca, and 0.14%–0.50% for Mg. Principal component and correlation analysis suggested a possible antagonistic interaction between leaf K and Mg. Negative associations were observed most frequently between Ca and Mg and other nutrients, especially K. Plant parameters such as bush volume, leaf size, and growth rate were closely related to soil and leaf K. Deficiencies in leaf tissue K and P were identified as potentially important factors limiting growth. Therefore, there is a need to adjust or balance the application of these nutrients. In conclusion, the sufficiency ranges derived can be used as a guiding principle in diagnosing the nutritional status of haskap cv. Indigo Gem on representative farms in Nova Scotia.

A randomized stratified survey was conducted in Alberta in 2017 to determine the distribution and abundance of multiple-resistant [acetolactate synthase (ALS) inhibitor, glycine, and synthetic auxin] kochia. All populations were ALS inhibitor resistant, with glyphosate and dicamba resistance confirmed in 50% and 18% of populations, respectively. Ten percent of populations exhibited resistance to all three mode-of-action herbicides.

AAC Comfort is a high-yielding, semi-leafless, green cotyledon field pea (Pisum sativum L.) cultivar developed at the Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, in Lacombe, AB. It is adapted to all field pea growing regions in western Canada. AAC Comfort has late maturity, medium lodging resistance, medium seed size, round seed shape, and good bleach resistance and green colour intensity. It is resistant to powdery mildew caused by Erysiphe pisi DC., moderately susceptible to mycosphaerella blight caused by Mycosphaerella pinodes (Berk. & Blox.) Vestergr., and susceptible to fusarium wilt caused by Fusarium oxysporum f. pisi (Linford) Snyd. & Hans.

AAC Warman (BW1025) is a high-yielding Canada Western Red Spring (CWRS) wheat adapted to production in western Canada. AAC Warman was 3% higher yielding than Unity, the highest yielding check in the Central Bread Wheat Cooperative registration trials (2014–2016). Within the same test, AAC Warman was 11% higher yielding than Carberry, a popular CWRS wheat variety across the Canadian prairies. AAC Warman matured 3 d earlier than Carberry and a day later than Unity, the earliest maturing check. AAC Warman was shorter than Unity and had better stem strength compared with Unity; however, the lodging score for AAC Warman was higher than the mean of the checks. Over 3 yr of testing (2014–2016), the test weight and thousand-kernel weight of AAC Warman was similar to Carberry. The grain protein content of AAC Warman was 0.3% lower than both Unity and Carberry. AAC Warman was rated moderately resistant to Fusarium head blight (Fusarium graminearum Schwabe) and loose smut [Ustilago tritici (Pers.) Rostr.], resistant to leaf rust (Puccinia triticina Erikss.) and stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. & E. Henn), moderately susceptible to stripe rust (Puccinia striiformis Westend.) and common bunt [Tilletia caries (DC.) Tul. & C. Tul.], and intermediately resistant to leaf spot complex. AAC Warman was resistant to orange wheat blossom midge (Sitodiplosis mosellana Géhin). Based on its milling and baking performance over 3 yr (2014–2016), as evaluated by the Grain Research Laboratory, Canadian Grain Commission, AAC Warman was registered under the CWRS market class.

AAC Carver is a semi-leafless, yellow cotyledon, high-yielding field pea (Pisum sativum L.) variety developed at the Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, Canada. It has a maturity of 96 d, seed size of 226 g, and good lodging resistance. AAC Carver is resistant to powdery mildew (caused by Erysiphe pisi DC.), and moderately susceptible to mycosphaerella blight [caused by Mycosphaerella pinodes (Berk. & Bloxam.) Vestergr.] and fusarium wilt [caused by Fusarium oxysporum f. pisi (Linford) Snyd. & Hans.]. AAC Carver is adapted to all field growing regions in western Canada.