The objective of this study was to investigate the effect of spring tillage on glyphosate-resistant giant ragweed emergence pattern. Giant ragweed emerged from late Mar. until early June and tillage had no effect on total seedling emergence and days required to reach 50% cumulative emergence (T₅₀); however, results differed between years.

Herein we describe a new method to rapidly determine the n-6/n-3 fatty acid ratios in cereal grains and forages (hydroponically-grown cereal sprouts and haylage) using ¹H nuclear magnetic resonance (NMR) spectroscopy. This NMR method was found to be consistent with more established but time-consuming gas chromatographic methods (R = 0.994).

Eight trials were conducted during 2012–2014 to determine the response of non-2,4-D resistant soybean to 2,4-D tank contamination at 2.1–168 g a.e. ha^-1. The predicted dose of 2,4-D to reduce yield 1%, 5%, 10%, 20% or 50% was 4.5, 22, 46, 97, and >168 g a.e. ha^-1, respectively.

Molecular markers reported to be linked to extreme resistance (ER) against Potato virus Y (PVY) were evaluated in potato germplasm. YES3-3A and YES3-3B, markers linked to Ry _sto, were detected in ‘Barbara’ and its three descendants that exhibit ER to PVY; RYSC3, a marker linked to Ry_adg, was detected in breeding clones NY121 and NY123. Assessment of RYSC3 as a marker for selection for Ry_adg-mediated ER validated its efficacy in identification of selections with ER to PVY.

Various preemergence (PRE), PRE followed by postemergence (POST), and POST weed control options for conventional soybean were evaluated. More than 90% control of selected weed species were observed for most treatments. However, weed interference in plots treated with S-metolachlor metribuzin or S-metolachlor metribuzin cloransulam-methyl resulted in reduced soybean yield.

Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume that has received renewed interest in western Canada because of its desirable forage characteristics. The objective of this review is to summarize previous studies on the agronomy, forage yield, nutritive value, seed characteristics, and diseases and pests of sainfoin. In addition, the review also focuses on the genetic diversity and registered cultivars of sainfoin and their potential use in temperate grasslands. Past studies have reported that sainfoin has a high nutritive value, and high voluntary intake and palatability to grazing animals. In western Canada, dry matter (DM) yield of sainfoin is 80%–95% that of alfalfa (Medicago sativa L.). Unlike other legumes such as alfalfa, sainfoin does not cause bloat in grazing animals due to the presence of condensed tannins. Sainfoin is suitable for monoculture or binary mixtures with either grasses or alfalfa. Genetic diversity studies revealed that sainfoin germplasm generally has high variation within populations. Genetic variation among plants provides an opportunity to develop improved cultivars with desirable characteristics. However, compared with the other forage legumes, sainfoin is still an underdeveloped forage crop with few cultivars being available in western Canada. New sainfoin cultivars with high DM yield and persistence under regional growing conditions are required.

This research examined the effect of pod elimination on growth and N₂ fixation ability in three annual Medicago species during drought stress and subsequent recovery. This study was carried out as a factorial experiment based on a completely randomized design with four replications. The treatments included annual Medicago species, presence or removal of the pod, and water stress at four levels: 100% (as a control), 80%, 60%, and 40% field capacity (FC) during the period of stress. The results showed that annual Medicago species can be considered as semi-drought tolerant species and their recovery ability from mild and moderate drought stress is relatively good. M. polymorpha performed better and showed higher recovery ability in comparison with other tested species. The results of this study showed that elimination of pods from annual Medicago species before sowing enhanced seedling performance under drought stress. However, the effect of pod elimination showed higher significance on growth parameters than nitrogen fixation. The information from this research would be useful for better understanding the physiological basis of changes in drought resistance, as well as targeted breeding programs, to improve the performance of annual Medicago species under conditions of limited or scarce water supply.

Predicting crop development stages is fundamental to many aspects of agronomy (e.g., pesticides and fertilizer applications). Temperature is the main factor affecting plant development and its impact on crop development is often measured using thermal-time. We compared different thermal-time models to identify the best model for simulating spring wheat development in western Canada. Models compared include (i) North-Dakota growing-degree-day (NDGDD), (ii) growing-degree-day base-temperature zero (GDD₀), (iii) growing-degree-day base-temperature five (GDD₅), (iv) beta-function (BF), and (v) modified-beta-function (MBF). We utilised agro-meteorological data collected across western Canada from 2009–2011. Results showed that accumulated heat units/daily growth rates from the different models correlated well with spring wheat phenology with R² ≥ 0.91 and P < 0.001. However, when the developed models were used to predict time (calendar-days) from planting to anthesis for cultivar AC-Barrie, the BF and MBF models performed poorly. Average predicted times from planting to anthesis by NDGDD, GDD₀, GDD₅, BF, and MBF models were 63, 63, 62, 65, and 64 d, respectively; while the actual observed time was 60 d. Root-mean-square error (RMSE) for NDGDD was 4 d, 5 d for GDD₀ and GDD₅, and 6 d for BF and MBF. These findings suggest that simple GDD-based models performed better than more complex BF-based models.

Sugar beet (Beta vulgaris L.) has a long history as an option for irrigated crop rotations in southern Alberta. A 12-yr (2000–2011) study compared conservation (CONS) and conventional (CONV) management for sugar beet in 4- to 6-yr rotations which also included dry bean (Phaseolus vulgaris L.), potato (Solanum tuberosum L.), and soft white spring wheat (Triticum aestivum L.). Oat (Avena sativa L.) and timothy (Phleum pratense L.) were included in the longest 6-yr rotation. Conservation management incorporated reduced tillage, cover crops, feedlot manure compost addition, and solid-seeded dry bean. Compared with a 4-yr CONV rotation (52.2 Mg ha^-1), sugar beet root yield (averaged over the second 6 yr of the study, 2006–2011) was significantly higher, by 11%, on 4- and 5-yr CONS rotations (57.7–57.9 Mg ha^-1), and by 8% on a 6-yr CONS rotation (56.1 Mg ha^-1). Sugar beet impurity parameters were significantly affected by rotation in, at most, 3 of 12 yr. However, averaged over the final 6 yr of the study (2006–2011), a significantly higher K concentration (impurity) was found with CONS (2108 mg kg^-1) vs. CONV (1958 mg kg^-1) management. Integrating CONS management practices into sugar beet rotations led to significant yield benefits while effects on sugar beet quality were minimal.

Nine field studies were conducted during 2011 to 2013 in Ontario to determine the effect of flumioxazin residues on winter wheat. For early- and mid-fall applied flumioxazin, there was no impact of the interval, 1, 2 or 4 weeks pre-plant (WPP), between flumioxazin application and winter wheat planting on injury, plant height, and yield. Injury was low, ranging from 0% to 4%, and was generally higher when flumioxazin was applied at 142.8 g ai ha^-1 compared with 35.7 or 71.4 g ai ha^-1. For late-fall applications, there was greater injury in the fall when flumioxazin was applied 2 WPP vs. 1 WPP. When combined over flumioxazin rates, winter wheat injury was 16% to 24% and 0% to 3% at 2 and 1 WPP, respectively. Injury increased when the rate increased from 35.7 to 142.8 g ai ha^-1. Flumioxazin applied at 142.8 g ai ha^-1 caused 1%, 5%, and 6% injury when applied 1 WPP and 32%, 53%, and 37% injury when applied 2 WPP at 1, 2, and 3 weeks after emergence in winter wheat, respectively. In all studies, flumioxazin applied at 35.7, 71.4 or 142.8 g ai ha^-1 applied at various application timings caused no adverse effect on winter wheat height and yield.

To investigate the mechanism by which laser irradiation enhances the chilling tolerance of wheat seedlings, seeds were exposed to different treatments, and biochemical parameters were measured. Compared with the control group, chilling stress (CS) led to an increase in the concentrations of malondialdehyde (MDA) and H₂O₂, and decreases in the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), peroxidase (POD), and nitric oxide synthase (NOS), and the concentrations of nitric oxide (NO) and protein. Treatment with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), sodium tungstate (ST), and NG-nitro-L-arginine methyl ester (L-NAME) followed by CS resulted in further increases in the concentrations of MDA and H₂O₂ and further decreases in the other parameters. However, treatment with PTIO, ST, and L-NAME followed by laser irradiation had the opposite effects on these parameters. When the seeds were treated with PTIO, ST, and L-NAME followed by laser and CS, the concentrations of MDA and H₂O₂ were significantly lower and the other parameters were higher than in the PTIO, ST, and L-NAME plus CS groups. These results suggest that CO₂ laser irradiation enhances the chilling tolerance of wheat seedlings by stimulating endogenous NO synthesis.

Simple sequence repeat (SSR) markers can be applied to genotyping projects at low cost with inexpensive equipment. The objective of this study was to develop SSR markers from the publically-available genome sequence of Brassica rapa and provide the physical position of these markers on the chromosomes for use in breeding and research. To assess the utility of these new markers, a subset of 60 markers were used to genotype 43 accessions of B. rapa. Fifty-five markers from the 10 chromosome scaffolds produced a total of 730 amplicons, which were then used to perform a phylogenetic analysis of the accessions, illustrating their utility in distinguishing between a wide range of germplasm. In agreement with similar studies of genetic diversity, our markers separated accessions into distinct genetic pools including Chinese cabbage, Chinese winter oilseed, European winter oilseed, Canadian spring oilseed, pak-choi, turnip, and yellow sarson. The results further illustrate the presence of a high level of genetic diversity in B. rapa, and demonstrate the potential of these SSR markers for use in breeding and research.

Natural nitrogen isotope abundance (δ¹⁵N) has been suggested as a potential indicator for discriminating organic vegetables from their conventional counterparts. However, little is known about the δ¹⁵N characteristic of cauliflower (Brassica oleracea L. var. botrytis) under organic production and how the application of chemical fertilizers could affect this characteristic. In this study, δ¹⁵N characteristics of cauliflower (including the intra-plant δ¹⁵N characteristic) and soil under different fertilization treatments were investigated under field conditions. Five treatments were laid out: control, chemical fertilizers (F4M0), organic fertilizer (F0M4), and chemical fertilizer in combination with organic fertilizer at the ratio of 3:1 (F3M1) and 1:3 (F1M3). Results showed that plant δ¹⁵N was positively correlated with fertilizer δ¹⁵N and plant root/flower was more sensitive to changes of fertilizer δ¹⁵N and soil δ¹⁵N than leaf/stem. Distribution of δ¹⁵N in different plant parts (especially in flower and leaf) was significantly changed when organic fertilizers were partially or totally substituted by chemical fertilizers, suggesting a comparison of flower δ¹⁵N and leaf δ¹⁵N might be applicable for the organic identification of marketed cauliflowers. Our results provide fundamental data for the soil- and fertilizer-specific crop δ¹⁵N database and indicate that the intra-plant δ¹⁵N characteristic could be helpful for organic cauliflower identification.

The objectives of this study were to determine the effects of degree and duration of water stress on growth and seed production of glyphosate-resistant (GR) giant ragweed. The degree of water stress included giant ragweed response to 100%, 75%, 50%, 25%, and 12.5% of field capacity. The highest growth index (588 cm³) was achieved at 75% of field capacity with plants typically ≥125 cm tall and ≥57 leaves plant^-1. Giant ragweed seed production was ≥55, 35, 20, and 5 seeds plant^-1 at ≥75%, 50%, 25%, and 12.5% of field capacity, respectively. The study of duration of water stress included the response of giant ragweed to withholding water for 2, 4, 6, 8, and 10 d following 100% of field capacity. Water stress of 4 d or longer reduced giant ragweed plant height ≥20%, root and shoot biomass ≥66%, number of leaves ≥36%, growth index ≥54%, and seed production by 36% compared with 2 d of water stress. Results from this study indicate that giant ragweed can survive and produce seeds at 12.5% of field capacity or 10 d of water stress.

Flax is an important oilseed crop with industrial, animal, and human nutrition uses. Breeding programs for linseed and fibre flax were initiated in Canada in the early 1900s. A total of 82 flax cultivars have been registered in Canada since 1910, including 24 cultivars introduced from foreign countries and 58 cultivars developed by Canadian breeders. This study collated pedigree data of Canadian flax cultivars and quantified their genetic base via pedigree analysis and coefficient of parentage (CP). A fairly high mean CP of 0.14 was observed between all registered cultivars; this value was even higher (0.23) when only the 46 cultivars released from 1981–2015 were considered. The registered cultivars traced back to 46 ancestors; 72% originated from foreign countries and contributed 83% of the genetic base of all cultivars, illustrating the dominant role played by foreign germplasm in the genetic improvement of Canadian flax. The top 11 ancestors contributed 70%–93% of the genetic base of modern flax cultivars released in the last three decades and formed the core gene pool of Canadian flax cultivars. The genetic base of Canadian cultivars is relatively narrow, although it has gradually expanded, especially in the last two decades. Broadening the genetic base through the introduction of new exotic germplasm is needed to invigorate the gene pool of Canadian flax breeding programs.

The understanding of plant nutrient uptake and dynamics is a necessary step to develop site-specific, economically viable, and environmentally responsible management practices. A field study on canola (Brassica napus L.), treated with preplant and sidedress nitrogen (N) applications under ample phosphorus (P) supply conditions, was conducted to determine seasonal plant dry matter (DM) and N and P uptake patterns. We found that periodic DM measured at 20% flowering (FL), from FL to 50% pods reaching maximum size (FL-RI), and from RI to physiological maturity (RI-PM) contributed to 30%, 57%, and 14% of total DM, respectively. Yields ranged from 111 to 447 g m^-2 with a sharp decline in 2012 induced by heat and drought. The crop took up about 58%–71% of total plant N by FL, whereas up to 42% of total plant P was assembled during the RI-PM. Canola seed accounted for 60%–66% of total plant N and 59%–63% of total plant P. Accumulation of DM and N post-FL, and of P during RI-PM could explain 69%, 43%, and 55%, respectively, variations in yield, seed N, and seed P. Our data indicated that plant P uptake under adequate P supply conditions in canola was largely enhanced by N application.

Green manure crops may have a role to play in the development of sustainable agricultural systems in the semiarid northern Great Plains of North America. This study determined the benefits of different green manure crops, seeding dates, and termination methods on soil nitrogen, phosphorus, and moisture, as well as the performance of durum wheat following green manures the following year. Field experiments were conducted at Swift Current, Saskatchewan, from 2006 to 2009. Three green manure crops [forage pea (Pisum sativum L.), chickling vetch (Lathyrus sativus L.), and black lentil (Lens culinaris Medik.)] were seeded in May, June, and July, and terminated at full bloom using glyphosate, rototilling or by frost. Other treatments included summerfallow and stubble of selected crops harvested for grain or silage. Different green manure crops, seeding dates or termination methods had similar effects on soil moisture, available N, and exchangeable P at termination or the following spring. These effects of green manure management on soil residual characteristics were comparable to those observed under summerfallow, but higher than those on grain or silage stubble. Therefore, green manure is a viable alternative to summerfallowing and could be seeded any time during the growing season. If seeded late, green manure could be terminated by frost, thus saving on costs.

Taraxacum Kok-saghyz (L.E. Rodin) (TKS) is a natural source of rubber. There is a rising interest in TKS establishment as a new crop in Ontario. Trials were conducted at Simcoe and Guelph, Ontario between 2013 and 2014 to explore the possibility of establishing TKS plants from seed in fields in Ontario. The effects of seeding depth, watering regimes, polymer, and covering mulch on the recruitment of TKS were explored. It was found that TKS displays very low field recruitment levels regardless of treatment. KNO₃ did not have any significant effect on TKS seed germination. Seedling emergence was greatest when seeds were placed on the soil surface and decreased with increasing seeding depth. Two years of field experiments highlighted that TKS seedlings recruit better in moderate conditions when the temperature is optimum for TKS germination (warm but not hot, <25 °C). TKS seedlings recruited better at Simcoe (with a sandy soil type) than at Guelph (with a loamy soil type). Overall, however, field recruitment from seed was low (15% at best) and these results suggest that establishing TKS from seed in Ontario fields remains a challenge.

Leaf spots (LS) of wheat continue to be widespread in western Canada. Most registered cultivars do not have a good level of resistance, thus it is important to evaluate the impact of agronomic practices. This study examined LS severity of spring wheat in a cropping sequence trial under conservation tillage, and compared it to results from two other agronomic trials conducted under different environmental conditions in the same area two decades earlier. In the present study, wheat grown after fallow generally had lower LS severity than wheat grown after another wheat crop, regardless of the sequence, with wheat grown after non-cereals (crop or green manure) having among the lowest disease levels. In most cases there were no differences in disease within phases of each sequence. Grain yield was highest in wheat grown after fallow or green manure than in wheat grown after another wheat, regardless of the sequence. Some of these results were different than those reported from studies conducted before, under conventional or conservation tillage, in particular in regards to disease levels after a fallow year, and the frequency of Pyrenophora tritici-repentis and Phaeosphaeria nodorum. Climatic conditions in the years of the present study (2010–2013) were different than when the previous studies were conducted (1993–1996), especially in regards to temperatures over the previous fall/winter and precipitation in the growing season, which were all higher in the most recent period. How these differences might have affected the survival and reproduction of the LS pathogens, and disease development, are discussed.

Artificial light in growth chambers typically has a higher red to far-red (R:FR) ratio compared with natural light. This higher ratio may delay flowering and reduce plant height in some long-day plants. Modification of light spectral quality to lower than the critical threshold of R:FR for a given plant species can have important implications with respect to plant structural and physiological traits. The objective of this study was to accelerate lentil (Lens culinaris) flower induction in growth chambers re-fitted with T5 fluorescent bulbs, using supplemental FR bulbs to re-balance the R:FR ratio. Lentil cultivars CDC Greenland and CDC Maxim were grown under three light sources differing in R:FR, namely light emitting diodes (LED; R:FR = 3.09), T5 fluorescent bulbs (R:FR = 5.6), and T5 supplemented with near far-red bulbs (R:FR = 3.1). All three light sources provided 500 µmol m^-2 s^-1 of photosynthetic photon flux (PPF). Lentil floral induction was significantly affected by the R:FR ratio. Plants grown under R:FR ratios of 3.1 or less flowered 10–11 d earlier than plants grown under an R:FR ratio of 5.6. Both cultivars had the same response to R:FR ratio in terms of days to flowering and flowering rate.

AAC Elie hard red spring wheat (Triticum aestivum L.) has grain yield and time to maturity within the range of the checks. AAC Elie has an awned spike, a low lodging score indicative of strong straw, and a short plant stature typical of a semidwarf. These traits were comparable to the check Carberry. AAC Elie expressed resistance to prevalent races of leaf and stem rust, and intermediate resistance to fusarium head blight, yellow rust, common bunt, and loose smut. Compared with the five Canada Western Red Spring checks, AAC Elie has improved flour yield, and lower flower ash. AAC Elie is eligible for grades of Canada Western Red Spring.