Plant and environmental factors affect root nitrogen (N) exudation dynamics in legumes. To better understand the genotypic variability and plant factors affecting root N release nodulation, plant growth, tissue N content, and root N exudation, six (three diploid and three tetraploid) red clover (Trifolium pratense L.) varieties were evaluated under controlled environmental conditions during the first 8 wk of plant growth after rhizobia inoculation. Genotypic differences were found for nodulation, plant dry weight (DW), leaf area, root attributes (root length, surface area, volume, and diameter), shoot and root N concentration, and N content. Genotypic differences were also found for root exudate N content in terms of NO₃^--N, NH₄ -N, and dissolved organic N (DON). In general, root exudate inorganic N content was greater in tetraploid varieties than in the diploids throughout the growth period. Root exudate DON content was greater than the inorganic N content. The NO₃^--N content in root exudate was positively correlated with root growth attributes and root N concentration, whereas NH₄ -N content was positively correlated with nodule number. Root exudate DON was positively correlated with shoot N concentration and average nodule DW. These results highlight the existence of genotypic differences among red clover varieties for plant morphological factors affecting root N release during the early stages of plant development.

Biological N₂-fixation underpins the role of pulse crops in the development of sustainable cropping systems, but it is uncertain how nodulation and N accumulation may differ with pulse species, cultivars, and environments. This 3 yr field study investigated nodulation at the early and late flowering stages and seed and straw N uptake for chickpea (Cicer arietinum L.), dry bean (Phaseolus vulgaris L.), faba bean (Vicia faba L.), field pea (Pisum sativum L.), and lentil (Lens culinaris Medik.). At early flowering, all pulses except dry bean had more nodules in the wetter (2010) than drier year (2009). Faba bean had the most nodules followed by field pea and chickpea, while the nodulation varied with plant growth stages and environments. For both pea and lentil, more nodules were observed at early flowering, but higher nodule biomass was obtained at late flowering. Chickpea had higher nodule biomass at late than early flowering but number of nodules varied with year. Seed N uptake was highest in field pea, whereas straw N uptake was highest in faba bean. Our results suggest a possibility of improving pulse N₂-fixation by targeting nodule numbers and nodule biomass, although the outcome of plant N uptake will vary with environments.

Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume widely distributed in the northern temperate regions of the world. Its genetic improvement has been relatively slow due, in part, to the lack of genetic information including molecular characterization of sainfoin germplasm. An attempt was made to evaluate genetic diversity and relationships among 38 sainfoin accessions collected from different regions of the world using amplified fragment length polymorphism (AFLP) markers. Five AFLP primer pairs were used to assess 367 individual plants, which produced 1042 polymorphic AFLP bands. The frequencies of the scored bands in all assayed individuals ranged from 0.003 to 0.973, with a mean value of 0.165. The analysis of molecular variance revealed higher within-accession (84.3%) genetic variation than among accessions (15.7%). The genetic distance based on inter-accession distance matrices was significant for most accessions but was not significant for accessions sharing similar parents. A dendrogram of the collected accessions showed two clusters at an inter-accession genetic distance coefficient of 0.36. The revealed information on genetic distance and genetic diversity of the sainfoin accessions is useful for selecting genetically diverse germplasms for sainfoin genetic improvement efforts.

Confirmation of glyphosate-resistant (GR) weeds in southwestern Ontario has led to a change in weed management practices, particularly in soybean. Registered soil-applied herbicides have been identified that have activity on GR common ragweed; however, due to the long emergence period of common ragweed, additional postemergence options are required. The recent development of glyphosate- and dicamba-resistant soybean (Roundup Ready Xtend soybean) allows for the preplant and postemergence application of dicamba. Three field studies were conducted in Ontario, Canada, in a field with confirmed GR common ragweed. Glyphosate-resistant common ragweed interference resulted in 75% yield loss in soybean compared with the weed-free check. At 4 wk after application, dicamba tank-mixed with glyphosate applied preplant only, postemergence only, or preplant followed by postemergence controlled GR common ragweed up to 94%, 87%, and 99%, respectively. The availability of dicamba for use in glyphosate- and dicamba-resistant soybean will provide an additional mode of action for weed management in soybean.

Garden potato varieties grown on more than 1.5 ha are subject to variety registration to be sold as seed potato in Canada. Prerequisites for the registration of varieties include the pedigree and breeding history as well as a morphological description. For most varieties, no pedigree or morphological description is available, and furthermore, some groups are essentially derived from one another. Therefore, a review to determine the genetic and morphological similarities and uniqueness of some of the garden potato varieties was initiated. Seven garden potato varieties grown over the largest areas in Canada were genotyped using a set of nine microsatellite [simple sequence repeat (SSR)] markers, resulting in six distinct SSR profiles. These varieties were also grown out for morphological description, providing supplementary information for the national registration and their monitoring during the seed certification process. To further assess the genetic similarities of garden or heritage varieties, 84 potato varieties were genotyped, and the unique SSR profiles of 62 varieties and six SSR profiles shared among the other 22 varieties were added to the Canadian Food Inspection Agency potato variety reference SSR profile collection. Furthermore, a set of blue varieties were described morphologically to evaluate the nature of morphological characteristic variation of varieties sharing the same SSR profile. Although all 14 varieties grown show some morphological differences, all varieties within each group sharing an SSR profile also clustered together based on morphological characteristics.

Blue honeysuckle (Lonicera caerulea L.) is a novel fruit crop that stands out for its northern climatic adaptation. Understanding spring phenological adaptation to temperate climate is central to development of a broader range of production and greater mainstream crop potential. In 2012 and 2013 across three sites in the Fraser Valley, British Columbia, spring phenophases from bud break to fruit harvest were determined across three foundation groups. Genetic variability is characterized for Russian, Japanese, and Kuril blue honeysuckle foundation groups used in breeding at the University of Saskatchewan, Saskatoon, SK. Germplasm group membership is the principal feature of phenological adaptation. Although temperate climate adaptation is limited in the Russian germplasm, the intermediate Japanese and later Kuril spring phenology provide an adequate degree of temperate climate adaptation to facilitate commercial production. These findings demonstrate that blue honeysuckle has phenological adaptation to a temperate climate. Diversity between and within genetic groups presents opportunities for crop enhancement, especially through breeding for later bloom periods.

Currently, no in-crop herbicide is registered to control wild oat (Avena fatua L.) in tame oat (Avena sativa L.). Wild oat must be controlled in tame oat using other agronomic practices. The objective of this research was to determine if side-banded phosphorus (P) in combination with seeding rate would increase the competitiveness of tame oat with wild oat, increasing yield and quality. An experiment was conducted from 2003–2005 at Indian Head, SK. The experimental design was a strip-plot design with four replications. The strips were low and high wild oat density. A two-way factorial, seeding rate (150, 250, 350, and 450 plants m^-2), and P rate (0, 15, and 30 kg P₂O₅ ha^-1) were seeded across the strips. Phosphorus affected seed density, grain yield, oat biomass, and wild oat fecundity. Seeding rate affected most of the measured variables and interacted with wild oat and year. The application of P increased the competiveness of oat by increasing crop biomass by 7.6% and grain yield by 3.4% and decreasing wild oat seed from 1.26% to 0.76% in the harvested grain. Wild oat decreased grain yield by 23% in 2003, 4.4% in 2004, and 11% in 2005. Increasing the seeding rate increased grain yield by 5% when wild oat was present. Wild oat did not interfere with the uptake of side-banded P. Producers need to use both P fertilization and higher seeding rates to improve the competitiveness of tame oat and the management of wild oat in tame oat.

The classic A1 locus in sweet pea (Lathyrus odoratus) was investigated by Bateson, Punnett, and Saunders in the early 20th century history of Mendelian genetics. The mutation, in the form of the pink and white cultivar ‘Painted Lady’, is known from the 18th century. We show that this locus is associated with a single base pair mutation (332 G/A) in the flavonoid 3′,5′-hydroxylase (F3′5′H) gene. This results in an amino acid change (111 glycine/aspartic acid) in the conserved substrate recognition site 1 of the enzyme. The mutant flower lacks the blue pigment delphinidin and is thus pink and white, rather than purple and blue as in the wild-type. This single amino acid change at a functionally important site appears to convert the enzyme from primary F3′5′H activity to a relatively efficient F3′H, as suggested by heterologous transformation into Arabidopsis PAP1D (a mutant line that produces anthocyanin constitutively).

Tillage and new herbicide options may be necessary for the control of herbicide-resistant wild oat. The efficacy of soil-applied herbicides such as pyroxasulfone can be influenced by edaphic factors and weed seed recruitment depth, which varies with tillage system. We investigated the effect of tillage and pyroxasulfone rate when applied in the fall and spring on wild oat biomass at three locations in Alberta in 2014–2015. The vertical position of wild oat seeds, with and without tillage, was examined at each site. Wild oat biomass was greater in untilled plots compared with plots with fall tillage at all locations. In two out of three locations, pyroxasulfone efficacy was superior when applied in the fall compared with spring, possibly influenced by low spring rainfall. A single tillage pass at the Edmonton and Kinsella locations did not affect wild oat seed distribution, but there was an increase in seeds present in the surface layer in the untilled treatment at Lacombe. Tillage, used in combination with soil-applied herbicides, may be an option to achieve acceptable control of herbicide-resistant wild oat.

Sea buckthorn (Hippophae rhamnoides L.) is used in beverages, pharmaceuticals, cosmetic products, and animal feeds. Although sea buckthorn has been shown to be easy to propagate vegetatively, currently, there is little information on reliable techniques to vegetatively propagate the plant repetitively within a single year. To address this, three experiments were conducted to study whether season and chilling affected the successful rooting of cuttings. Four cultivars, ‘Chuskaya’, ‘Golden Rain’, ‘Lord’, and ‘Sunny’, were used in the season- and chilling-effect experiments. Hardwood and softwood cuttings from field-grown plants did not root from October to December. The percent of rooted cuttings in January was cultivar-dependent. The number and percent of rooted greenhouse-produced cuttings were significantly affected by length of chilling. Most cuttings were produced and the highest percent rooted when the plants chilled for at least 6 wk. ‘Lord’ had the most and ‘Golden Rain’ the least number of rooted cuttings. This study indicated that greenhouse-grown stock plants were a viable source of sea buckthorn cuttings for vegetative propagation. When combined with field-grown sources, it is possible to produce sea buckthorn planting material year-round.

Black walnut (Juglans nigra L.), a large tree native throughout the eastern United States, produces a high-quality edible nut. Our goal was to maintain the integrity of black walnut breeding programs by verifying the identity of accessions. We sampled 285 ramets of 78 cultivars from the black walnut nut breeding orchards and clonal repositories at the University of Missouri and Kansas State University. We employed both phenotypic and genotypic methods to identify and differentiate cultivars. Phenotypes were evaluated using seven phenological traits. Cultivars varied for all traits among each of the 4 yr, but the best morphological characteristics for evaluating cultivar identity were bud break date and date of first pistillate bloom. Samples (n = 285) were genotyped using 10 polymorphic microsatellite loci. The simple sequence repeats produced a total of 174 alleles and 17.2 alleles per locus. We detected 47 unique genotypes represented by more than one sample, including 128 instances of identical genotypes with different names (synonyms) and 106 instances of different genotypes with a shared name (homonyms). Our results indicated that multiple errors were committed during the propagation of these important cultivars. It may be difficult to determine which genotype is original to a cultivar name in the absence of a foundation plant materials collection or vouchered specimens. These results will assist black walnut breeders and producers by improving the integrity of breeding collections and by identifying the best phenological traits for rapid assessment of trueness to type.

There are a limited number of herbicide options that provide commercially acceptable control of yellow nutsedge in corn. A study consisting of nine field experiments was conducted during 2013–2016 in growers’ fields in Ontario to evaluate the efficacy of glyphosate plus various rates of halosulfuron applied after emergence (postemergence, POST) for the control of yellow nutsedge in glyphosate-resistant corn. Glyphosate (900 g a.e. ha^-1) plus halosulfuron applied POST at the registered rate of 34–68 g a.i. ha^-1 caused minimal injury in glyphosate-resistant corn. The predicted halosulfuron rates needed to control yellow nutsedge 50%, 80%, and 90% were 3, 24, and >140 g a.i. ha^-1 at 4 weeks after herbicide application (WAA) and 2, 13, and 73 g a.i. ha^-1 at 8 WAA, respectively. The predicted halosulfuron rates required to reduce yellow nutsedge density 50%, 80%, and 90% were 13, 42, and 109 g a.i. ha^-1, respectively. In addition, the predicted halosulfuron rates required to reduce yellow nutsedge dry weight 50%, 80%, and 90% were 6, 23, and 54 g a.i. ha^-1, respectively. Contrasts comparing halosulfuron (35 g a.i. ha^-1) with other herbicides showed that glyphosate plus halosulfuron provided as much as 35% greater control of yellow nutsedge than glyphosate plus bentazon (1080 g a.i. ha^-1) and as much as 22% greater control of yellow nutsedge than glyphosate plus tembotrione/thiencarbazone (45 g a.i. ha^-1).

To evaluate the forage yield and quality of seven perennial native species in monoculture and binary mixtures under a range of climate conditions, a 6-yr field experiment was conducted at the Swift Current Research and Development Centre (SCRDC), Agriculture and Agri-Food Canada (AAFC), in Swift Current, SK. Seven native perennial forage species from three functional groups (C₃, C₄ grasses, and legumes) were seeded in 2010 in monocultures and binary mixtures. Forage yield and quality [crude protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), phosphorus (P), calcium (Ca), and copper (Cu)] were measured during the first week of July and last week of August in 2011–2016. Mixtures that included western wheatgrass [Pascopyrum smithii (Rydb.) Löve] (WWG) tended to produce a greater yield when 90% of the composition within these mixtures was WWG. Adding bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Löve] (BBW), little blue stem [Schizachyrium scoparium (Michx.) Nash] (LBS), and prairie clovers (Dalea spp.) to the binary mixtures can increase the positive aspects of species diversity on stability and productivity in seeded pastures. Among the grasses, WWG contained higher crude protein and lower ADF and NDF concentration. Mixtures of forage species produced higher forage yield compared with monocultures. Native forage species can produce stable forage yield across very different climate situations. In mixtures, WWG showed promising results in forage productivity and quality and can be a suitable option for seeded pastures.

Halo blight, caused by Pseudomonas syringae pv. phaseolicola, is a seed-borne disease of dry bean (Phaseolus vulgaris L.) that lowers seed quality and yield. Over 2 yr, laboratory and field studies were conducted to evaluate the effect of microwave radiation on two market classes: navy (‘Envoy’) and white kidney (‘GTS 402’) bean. In the laboratory, seed germination and vigour decreased up to 15% after 40 s of microwave exposure, where <7% decrease was observed during 0–30 s. Disease plating showed no correlation between pathogen colonization of the seed and microwave radiation, as incidence of pathogen colonization was low across all exposure times. In field trials in Morden and Winkler, MB, microwave radiation was tested alone and in combination with copper hydroxide 53.8% and pyraclostrobin fluxapyroxad metalaxyl. Seed treatment with copper hydroxide slightly decreased the incidence of halo blight but had little impact on seed pick, hundred-seed weight, yield, or return on investment. Pyraclostrobin fluxapyroxad metalaxyl seed treatment had no effect on any of these parameters. Microwave radiation lowered seed emergence by up to 9% but did not reduce disease incidence and severity or increase yield or return of investment when applied alone or in combination with a chemical treatment.

Little information exists on the management and range health (RH) of northern temperate pastures, where health is defined as the ability to sustain ecosystem function. We surveyed 102 pastures for RH and their associated managers during 2012–2013 across central Alberta, Canada. Pastures were generally diverse mixes of introduced grasses and contained few legumes, despite most (55%) being seeded to legumes. The majority of pastures were healthy (mean RH score = 78.8% ± 1.3%), with 2.9% having scores <50%. Criteria reducing scores were noxious weeds, bare soil, and evidence of erosion. Most pastures had a reported history of cultivation (75.5%), with those previously cultivated and seeded to introduced forage having greater stocking rates [6.18 ± 0.91 animal-unit-months (AUM) ha^-1] compared with those lacking cultivation (2.14 ± 2.91 AUM ha^-1). Farms with horses or mixed livestock tended to practice year-round continuous grazing and supplemental hay feeding. Stocking rates on continuous and rotationally grazed pastures were similar regardless of grazing season, with the highest stocking on pastures used year-round (19.54 ± 2.03 AUM ha^-1) or throughout the dormant season (20.29 ± 3.10 AUM ha^-1). Use of management inputs was variable, with manuring and harrowing common and fertilizing, over-seeding, and aerating infrequent. Herbicide use was reported on 15.7% of pastures, despite 83.3% containing noxious weeds. Use of prescribed fire was rare, although 36.3% of pastures had evidence of fire. Industrial disturbances were reported on 48.3% of pastures. Overall, these results indicate that these pastures experience complex management and the limited decline in RH is due to high stocking under year-long grazing.

Early flowering is one of the major earliness traits in tomato and is also an important agronomical trait in crop plants; thus, this trait is important for plant breeding and crop improvement. With the innovation of rapid and cost-effective technologies, quantitative trait locus (QTL)-seq has become the preferred method of performing QTL identification. In the present study, we identified a candidate QTL of an early flowering trait in tomato (Solanum lycopersicum) using QTL-seq. Two DNA pools of the extreme phenotype of the F₂ progeny from crosses between the ‘Bone MM’ cultivar (early flowering, P₁) and ‘071-440’ cultivar (late flowering, P₂) were bulked for sequencing and an alignment analysis. We observed 220 single nucleotide polymorphism markers, seven candidate QTLs, and genes that may be associated with early flowering located between 1.6 and 71.8 Mb on chromosome 1. Using traditional QTL analysis, the location of one QTL was confirmed in the physical region between 23.5 and 25.3 Mb, which corresponded to the region identified using QTL-seq, and was referred to as EF1 (Solyc01g017060). A real-time quantitative reverse transcription polymerase chain reaction analysis showed that EF1 was the most highly expressed among the candidate genes and significantly expressed in early flowering parents and furthermore, we found that EF1, which had a similar sequence to the Ycf2 gene, may relate to the early flowering phenotype.

To address knowledge gaps around enhanced efficiency urea fertilizer efficacy for nitrogen (N) management, a study was designed to improve integrated nutrient management systems for western Canadian winter wheat producers. Three factors were included in Experiment 1: (i) urea type [urea, urea urease inhibitor—Agrotain^®; urea urease and nitrification inhibitor—SuperU^®, polymer-coated urea—Environmentally Smart Nitrogen^® (ESN^®), and urea ammonium nitrate (UAN)], (ii) application method (side-band vs. spring-broadcast vs. 50% side-band: 50% spring-broadcast), and (iii) cultivar (AC Radiant hard red winter wheat vs. CDC Ptarmigan soft white winter wheat). The Agrotain^® and CDC Ptarmigan treatments were removed in Experiment 2 to allow for additional application methods: (i) fall side-band, (ii) 50% side-band — 50% late fall broadcast, (iii) 50% side-band — 50% early spring broadcast, (iv) 50% side-band — 50% mid-spring broadcast, and (v) 50% side-band — 50% late spring broadcast. CDC Ptarmigan produced superior grain yield and N utilization over AC Radiant. Grain yield and protein content were influenced by N form and application method. Split applications of N usually provided the maximum yield and protein, particularly with Agrotain^® or SuperU^®. Conversely, the UAN and ESN^® forms, when all broadcast in spring, all side-banded in fall, or with late fall broadcasting, performed poorly. An exception to the poor fall-application results was the SuperU^® treatments, which produced similar yield to the highest-yielding treatments. The results suggest that split applications of N might be most efficient for yield and protein optimization when combined with an enhanced efficiency urea product, particularly with urease or urease nitrification inhibitors, and if the majority of N is applied in spring.

Recent canola acreage and production in western Canada have reached record high levels. Field experiments were conducted from 2014 to 2016 on land previously seeded to continuous canola for 6 yr at three Canadian Prairie sites. We determined that more intensive seed inputs, fertilizer, fungicide, tillage, or chaff removal could increase continuous canola yields compared with a “standard practice” (SP) treatment or match yields compared with canola in rotation. Recommended or 50% higher fertility levels alone or in combination with a higher seeding rate, tillage, chaff removal, or additional fungicide were applied to the same plots in three successive years to determine effects after 1, 2, and 3 yr of treatment imposition. In continuous canola, blackleg incidence and severity were both reduced by fungicide treatment. In rotations where canola was preceded by wheat, blackleg incidence and severity were much lower than in continuous canola. None of the treatments improved continuous canola yields compared with SP after a single year of treatment imposition. In subsequent years, canola yield increases compared with SP usually occurred as a result of additional fertilizer, seed, or fungicide. In the final year, canola yield loss due to continuous canola was largely rescued by additional seed and fertilizer. Without additional inputs, and when preceded by a different crop, canola yields averaged 11% greater than the average of all continuous canola treatments. High fertility regimes generally reduced oil content and increased protein content relative to standard fertility in continuous canola or relative to canola preceded by wheat.

Transplanting of micropropagated blackberry plugs in the field during late summer and early fall is a common nursery practice for commercial blackberry production. During this field transition, blackberry plants generally experience different stresses in addition to transplanting shock coupled with sudden exposure to low night temperatures in the fall. Improving the stress resilience of field-transplanted blackberry plants by recruiting plant endogenous protective metabolic responses has significant merit. Therefore, the aim of this study was to improve stress resilience of newly transplanted ‘Chester Thornless’ blackberry in the field during fall transition through stimulation of phenolic antioxidant and proline-linked metabolic responses by using bioprocessed chitosan oligosaccharide (COS) as an elicitor treatment. Fourteen-week-old blackberry plugs were transplanted in the field in late July and COS was sprayed weekly in the run-off for a 6-wk period after transplanting. Total soluble phenolic content, total antioxidant activity, total proline content, proline dehydrogenase, and succinate dehydrogenase enzyme activity of blackberry shoots were evaluated weekly during and 1 wk after COS application. Improvement in total soluble phenolic content and antioxidant activity based on 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging assay was observed in field-transplanted blackberry at 6 and 7 wk with COS elicitation treatment.

Low natural light levels during the winter months are a major limiting factor for greenhouse production in northern regions. To determine the effects of supplemental lighting (SL) on winter greenhouse production of pea shoots, crop growth, yield, and quality were investigated under the treatments of supplemental photosynthetic photon flux density (PPFD) of 50, 80, 110, and 140 µmol m^-2 s^-1, all with a 16 h photoperiod, plus a no-SL control treatment, inside a Canadian greenhouse from December to March. Light-emitting diodes with a red to blue PPFD ratio of 4:1 and peak wavelengths at 665 and 440 nm were used for the lighting treatment. During the trial period, the average natural daily light integral (DLI) inside the greenhouse was 5.3 mol m^-2 d^-1 and the average daily temperature was around 13 °C. Compared with the no-SL control, SL of 50–140 µmol m^-2 s^-1 increased stem length and leaf number before the first harvest and promoted the cumulative yield (kg m^-2) of pea shoots throughout the five harvest times. The total yield (kg m^-2) of five harvests and weekly average stem extension rate were proportional to supplemental PPFD within the range of 0–140 µmol m^-2 s^-1; however, SL of 50–80 µmol m^-2 s^-1, corresponding to total (natural supplemental) DLI of 8.1–9.8 mol m^-2 d^-1, resulted in the best integrated quality based on the evaluation of individual fresh mass, soluble solids content, succulence, and firmness. Therefore, a total DLI ranging between 8.1 and 9.8 mol m^-2 d^-1 can be suggested as a target for winter greenhouse production of pea shoots under conditions similar to this trial.

Preharvest fruit drop (PFD) of apple (Malus domestica Borkh.) can cause significant losses resulting in up to 50% reduction in yield in some years. In a 2-yr study, ‘Honeycrisp’ trees were treated with six foliar treatments including 20 mg·L^-1 1-naphthaleneacetic acid (NAA) 2 wk before anticipated harvest (WBAH), 125 mg·L^-1 aminoethoxyvinylglycine hydrochloride (AVG) 4 WBAH, AVG plus NAA 2 WBAH, and repeat sprays of 200 mg·L^-1 B, and 2000 mg·L^-1 Mg applied 48–93 d after full bloom to evaluate their effect on PFD and fruit quality. Fruit drop associated with broken pedicels and physiological causes was monitored. During a year with ∼43% PFD on untreated control trees, AVG retained up to ∼35% and NAA retained up to ∼27% of the total fruit number, relative to the control trees. The combination of AVG plus NAA had similar PFD compared with AVG alone, while B and Mg were similar to the control. The proportion of PFD associated with broken pedicels was ∼5%. Aminoethoxyvinylglycine delayed starch degradation, ethylene evolution, and blush skin colour development of fruit. This study supports the use of AVG 4 WBAH and NAA 2 WBAH to manage ‘Honeycrisp’ PFD, which may offer economic advantages for growing quality apples. Foliar sprays of Mg or B failed to reduce PFD.

Five generally recognised as safe (GRAS) salts with antimicrobial activity were investigated for their potential use as bactericides for the control of lettuce varnish spot [Pseudomonas cichorii (Swingle) Stapp]. The phytotoxicity of salts was first assessed using greenhouse and in vitro assays. Greenhouse assays revealed that salts showed different levels of phytotoxicity. Potassium sorbate, sodium benzoate, and sodium carbonate at higher concentrations caused a noticeable decrease of growth along with foliar phytotoxicity symptoms while sodium metabisulfite and sodium bicarbonate caused exclusively foliar symptoms. Based on the phytotoxic doses 5% determined in vitro, salts can be ranked in ascending order of phytotoxicity as follows: sodium bicarbonate, potassium sorbate, sodium carbonate, sodium benzoate, and sodium metabisulfite. When applied at concentrations causing mild to moderate foliar symptoms of phytotoxicity and no noticeable effect on growth, salts did not significantly affect (p ≤ 0.01) survival of P. cichorii on lettuce leaf tissue and did not significantly reduce (p ≤ 0.01) varnish spot severity. Although sodium metabisulfite was applied at concentrations higher than the minimum inhibitory concentration and minimum bactericidal concentration, it did not affect P. cichorii survival on leaf tissue.

Golden paintbrush (Castilleja levisecta Greenm.) is a hemiparasitic herbaceous perennial native to the Pacific Northwest of North America and is considered critically imperilled with only 11 populations remaining in the wild. The main objective of this study was to develop ex situ and in situ conservation through micropropagation and field plantings. In vitro cultures were initiated using nodal explants from two plants raised from seeds collected from a natural population. Shoots were then multiplied on Murashige and Skoog basal medium with 2.0 µmol L^-1 6-benzylaminopurine (BA), 3.0 µmol L^-1 kinetin (Kn), 2.2 g L^-1 phytagel, and 3% sucrose. Explant position on source plants, culture vessel design, and application of different plant growth regulator levels for BA, Kn, and thiadiazuron (TDZ) were tested to optimize micropropagation protocols. Clones from the plants showed differences in plant height and number of nodes in response to various BA and TDZ concentrations. In vitro shoots were successfully rooted under ex vitro conditions using commercial rooting powder (0.8% indole-3-butyric acid) with an average of ∼17 roots per shoot and acclimatized in the greenhouse with 100% survival rate. Two-month-old plants were transferred to a Parks Canada restoration site at Fort Rodd Hill, Victoria, BC, with 7.5% survival. The use of micropropagation in combination with reintroduction efforts offers an excellent opportunity for conserving endangered plant biodiversity in vitro and facilitating in situ conservation efforts by providing plants for reintroduction.

Applying pig manure in excess of crop demand can result in nutrient loss to water bodies. We studied the effect of liquid and solid pig manures and their N- and P-based application rates on yield and nutrient uptake in annual and perennial cropping systems for 3 yr. The experiment had a split-plot design with five nutrient management treatments including liquid-N (annual N-based liquid pig manure), liquid-P (P-based liquid pig manure once every 5 yr), solid-N (annual N-based solid pig manure), solid-P (P-based solid pig manure once every 5 yr), and control (no manure). The liquid-P treatment showed high apparent nitrogen and phosphorus recovery (ANR and APR, respectively) in each cropping system and yields similar to that of the liquid-N treatment. The solid-N treatment had the smallest ANR in the perennial cropping system (9%–27%) and also the smallest APR in both cropping systems (typically <4%) possibly due to N deficiency and high P application rate. The current formula for estimating organic N mineralization overestimated the available N, particularly for solid pig manure, reducing crop yield. Based on the ANR obtained in this study, a more appropriate coefficient is 10%–15% of the organic N from solid pig manure for no-till perennial cropping systems.

A Just–Pope production function is employed to investigate the effects of historic weather changes on hard red spring wheat yield variability in Manitoba. Field-level data on wheat yield, proportion of wheat seeded area, and fertilizer inputs from the Manitoba Agricultural Services Corporation were employed to determine how temperature and precipitation affect mean wheat yield and production risk, and how projected climate scenarios impact yield variability in heterogeneous risk areas of Manitoba. Variety richness increases average yield and reduces yield variance while varieties protected by plant breeders’ rights increase yield variance. Phosphorus fertilizer is positively associated with average wheat yield while total precipitation is shown to negatively affect mean yield and positively impact yield variability. June precipitation matters while June and July temperatures negatively affect yield. Projected climate change is expected to increase yield variability in both the medium (2034–2050) and long term (2079–2095), both under low- and high-carbon scenarios with production variance effects differing across crop districts. Adaptation strategies may be required to mitigate yield risk effects of climate change resulting in late seeding decisions from increased spring precipitation.

AAC Bloomfield is a six-row spring feed barley (Hordeum vulgare L.) cultivar with high yield, high test weight, high seed weight, and good lodging resistance. It performed well in the Maritime Six-Row Barley Registration and Recommendation Test (2013–2016) before being registered in 2017. AAC Bloomfield was developed by the Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON. AAC Bloomfield is recommended for barley growing areas in the Maritime provinces.

AAC W1876 hard red spring wheat (Triticum aestivum L.) has grain yield and time to maturity within the range of the check cultivars: Katepwa, Laura, Lillian, Carberry, and CDC Kernen. AAC W1876 has an awned spike, a low lodging score indicative of strong straw, and a short plant stature typical of a semidwarf wheat. AAC W1876 expressed resistance to prevalent races of leaf rust, moderate resistance to stem rust, and intermediate resistance to Fusarium head blight, yellow rust, common bunt, and loose smut. Compared with the Canada Western Red Spring check cultivars, AAC W1876 had improved flour yield and lower flour ash. AAC W1876 is eligible for grades of Canada Western Red Spring.