Canadian Journal of Plant Science

The coinciding increase in genomics resources for weedy plant species and herbicide resistance evolution has led to a rapid expansion of our understanding of the relationship between genomic structural variation and herbicide resistance mechanisms. Since the first discovery of EPSPS copy number variation conferring glyphosate resistance in Amaranthus palmeri, we have seen rapid convergent evolution of the same herbicide-resistance mechanism in eleven diverse weed species by a variety of unique structural variant generating mechanisms. These mechanisms include extrachromosomal circular DNA replication, unequal crossing over, and subtelomeric duplication. More recently, target-site duplication has been found to cause resistance for other herbicides with different modes of action including acetyl-CoA carboxylase (ACCase) inhibitors and glutamine synthetase inhibitors. Additionally, the first transposon-generated structural variants which confer herbicide resistances are beginning to be discovered. This review summarizes our current understanding of structural variation in agronomic weed genomes as it relates to herbicide resistance and emphasizes necessary future research to clarify the size, nature, and mechanisms that give rise to genomic structural variation. While we limit our review to herbicide resistance traits, this work also highlights the importance of structural variation as a critical component of total genetic diversity and its importance for the rapid evolution of novel traits.

In this study, we investigated the differences in soil physical and chemical properties as well as kiwifruit yield, between rain-shelter cultivation (BY) and open-field cultivation (CK) in Southwest China from 2020 to 2021. The results indicated that the BY treatment significantly improved the nutrient supply capacity of the soil and increased fruit yield. Compared with CK, soil moisture, bulk density, pH, total nitrogen, total phosphorus, total potassium, and organic matter content were lower under the BY treatment, whereas soil conductivity, available nitrogen, available phosphorus and available potassium were significantly higher. Principal component analysis (PCA) revealed significant differences in the soil physical and chemical properties between the two cultivation methods at each sampling period. Correlation analysis between yield and soil physical and chemical properties showed that except for pH, all indicators were highly correlated with yield (R2>0.87**). The BY treatment significantly increased yield by enhancing soil contents such as soil available nitrogen, phosphorus, and potassium, while reducing water content and bulk density. However, owing to the increase in soil electrical conductivity, there is a potential risk of salinization. To mitigate this, it is essential to supplement the soil with total nitrogen, total phosphorus, total potassium, and organic matter to maintain soil health.

Winter climate conditions, especially extremely low temperatures, constrain the production of fruit trees and other perennial crop species in Canada. Significant decreases in cold extremes under climate change may result in changes in plant hardiness zones and the distribution of crop species across the country. Climate warming might also bring changes to climate conditions that affect fall hardening, loss of cold hardiness due to winter thaws, and spring frost damages. Using the most up-to-date climate projections, we provide projected changes in the risks of damages to fruit trees during winter based on five agroclimatic indices and changes to the United States Department of Agriculture (USDA) plant hardiness zones based on long-term averages of annual extreme minimum air temperatures in the near-term (2030s, 2020-2049), mid-term (2050s, 2040-2069), and distant future (2070s, 2060-2089). Our results suggest that climate change might be beneficial for fruit trees across Canada with 1) improved fall hardening because of more time to acquire cold hardiness due to delayed first fall frost and 2) decreased winter coldness with increases in annual minimal temperatures and decreases in the accumulation of cold degree-days below-15°C. The risks of loss of cold hardiness due to winter thaws will increase slightly while the risks of spring frost damages to buds will be largely unchanged. Under a warmer distant

Ferula assa-foetida L., a perennial crop of the Apiaceae family has internal physical seed dormancy which inhibits its germination ability. Hence, to improve germination capacity and overcome seed dormancy, the present study was conducted using six accessions for assessing seed viability using 1% Tetrazolium test three times every 6 months and grown under three different temperature treatments (5°, 15°, and 25°C) during 2018-19 and 2019-20. These accessions were also grown under six different potting mixtures to optimize the best media for its survivability under field conditions. Share Abstract Ferula assa-foetida L., a perennial crop of the Apiaceae family has internal physical seed dormancy which inhibits its germination ability. Hence, to improve germination capacity and overcome seed dormancy, the present study was conducted using six accessions for assessing seed viability using 1% Tetrazolium test three times every 6 months and grown under three different temperature treatments (5°, 15°, and 25°C) during 2018-19 and 2019-20. These accessions were also grown under six different potting mixtures to optimize the best media for its survivability under field conditions. Results from the tetrazolium test indicated an average seed viability of 73.03% and showed a ~5 percent reduction during 2018-20. From germination tests, a chilling treatment of 5°C was found most effective for breaking dormancy. Besides, the seedlings grown under different potting mixtures showed that media mixtures in the combination of soil, sand, farmyard manure, and cocopeat were most appropriate for better germination stand. However, further studies are required to explain the agro-practices to cultivate this endangered plant at field capacity. It was also observed that genotypes EC966538 and EC968470 were best performers for overall germination as well as seedling survival parameters and could be used as base population in future selection and improvement breeding programs.

Pea-based intercrops provide nitrogen (N) benefits and often improve land productivity through functional diversification. However, their impact on grain quality and soil health remains unclear. We conducted a two-year (2021 and 2022) intercrop study at Swift Current and Melfort, Saskatchewan, assessing productivity, grain quality, and soil water-extractable organic carbon (WEOC) and water-extractable dissolved N (WEDN). Nine treatments included pea-oat (PO) intercrops with three N rates (0, ¼, and ½ of full recommended N rate for oat monocrop), pea-canola (PC) intercrops with three N rates (0, ¼, and ½ of full recommended N rate for canola monocrop), and three monocrops (pea, oat, and canola). Pea monocrop received no N fertilizer, while oat and canola monocrops received the full recommended N rate. In intercrops, pea was seeded at 2/3 and the companion crop at 1/2 of their recommended rates. Pea-oat intercrops consistently produced higher energy-based yields than PC intercrops. Intercrops outperformed monocrops at Melfort but not at Swift Current. Intercropping reduced canola protein content by 6-9% and oat protein content by 6-8%, compared to monocrops. Pea-oat intercrops increased WEOC level by 5-9% compared to monocrops. Pea- canola intercrops resulted in 10% higher WEDN than PO intercrops, attributed to a higher pea plant stand in PC. Nitrogen fertilizer rates in intercrops did not affect yields or soil labile C and N. The results showed that applying N fertilizers to pea-based intercrops did not improve productivity, but seeding rate ratio in intercrops should be finetuned based on crop competitiveness to improve overall performance.

AAC Planet is a semi-leafless and powdery mildew (caused by Erysiphe pisi Syd.) resistant field pea (Pisum sativum L.) variety developed at Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, Lacombe, Alberta, Canada. It has high yielding potential, late maturity, tall plant height with good lodging resistance, medium seed size, round seed shape, and low seed coat breakage. It has maturity of 100 days, and thousand-seed weight of 221 g with seed protein content of 24.6%. AAC Planet has a lodging score of 3.2 on the scale of 1–9. It is moderately susceptible to mycosphaerella blight (caused by Mycosphaerella pinodes) and fusarium root rot (caused by Fusarium avenaceum and F. solani).

Participatory plant breeding (PPB) has the potential to be an alternative to a centralized breeding model for niche markets that are historically underserved. Our objectives were to evaluate the performance of two parental cultivars from a Canadian PPB program: a modern spring wheat (Triticum aestivum L.) cultivar (5602HR) and a landrace (Red Fife) - with the progeny of the cross when selected by two farmers located 1800 km apart (denoted Farm1 and Farm2) and evaluate progeny differences from each other under organic conditions. Red Fife was 18 cm taller, matured 5 days later, had greater lodging susceptibility, greater seed mass, and 3.5% lower protein concentration than 5602HR. Farmer genotypes were similar to 5602HR in protein concentration and lodging severity, and similar to Red Fife in plant height (14 cm taller than 5602HR) and seed mass. Farmer genotypes did not yield differently from either parent. Farmer genotypes did not differ from each other in most parameters measured, however, Farm1 had greater lodging resistance under high fertility conditions than Farm2 despite similar plant height. This research provides a proof of concept for the role that farmer selectors can play in selecting for positive traits for organic production and provide insight into organic farmers’ preferences. The research also demonstrated that using an older landrace (ie., Red Fife) allowed positive features such as tall stature to be incorporated into the resulting progeny.

AAC McMurphy is a semi-leafless, yellow cotyledonary field pea (Pisum sativum L.) cultivar developed at Agriculture and Agri-Food Canada Lacombe Research and Development Centre, Lacombe, Alberta, Canada. It has a maturity of 90 days, one-thousand-seed weight of 246 g, and a lodging score of 2.9 on the scale of 1–9. The seed crude protein content of AAC McMurphy is 24.2%. AAC McMurphy is resistant to powdery mildew (caused by Erysiphe pisi) and moderately susceptible to mycosphaerella blight (caused by Mycosphaerella pinodes) and fusarium root rot (caused by Fusarium avenaceum).

Buckwheat (Fagopyrum esculentum Moench) is a common cover crop typically grown for its rapid establishment and superior weed suppression. One challenge of incorporating buckwheat into crop rotations, however, is its short generation time, which requires in-season management to prevent viable seed production and volunteers in subsequent crops. Mixing buckwheat at reduced seeding rates with other cover crop species is one way for producers to reduce volunteer potential; however, this may compromise weed suppression. To investigate mechanisms behind buckwheat weed suppression and how using buckwheat in mixtures can affect suppression, we collected a series of morphological measurements in buckwheat monocultures and in three, two-way and four, three-way cover crop species mixtures and modeled their response over the growing season. We found that while buckwheat height and relative growth rate were unaffected with increasing species richness, there was a significant reduction in maximum leaf area index (3.75 vs. 2.85 vs. 2.82 cm2 cm-2) in mixture. Buckwheat monocultures provided superior season-long weed suppression compared to mixtures (85% vs. 53% vs. 50%). Principal component analysis showed that increased height and leaf area index values were associated with greater weed suppression. The link between reduced leaf area index and weed suppression in mixtures compared to buckwheat monocultures suggests that the rapid leaf development and canopy cover associated with buckwheat is a key mechanism behind weed suppression. In practice, producers should expect a dilution effect and weed suppression to be compromised when the buckwheat seeding rate is reduced in mixtures.

For temperate climate, there is little information on the effects cover crops grown in fall (CCs) on the nitrogen (N) supply for next year's sugar beet (SB). Four field trials were conducted on silty soils to establish the CC N effect (Neff) compared to bare fallow separately for the periods sowing-summer and summer-autumn harvest. Biomass characteristics of radish (Raphanus sativus L.), spring vetch (Vicia sativa L.), saia oat (Avena strigosa Schreb.), and winter rye (Secale cereale L.) CCs before winter, soil mineral nitrogen in spring (SMN), and SB N accumulation and sugar yield (SY) were measured. In the period sowing-summer, characterized by a high SB N demand, Neff of overwintering, high biomass yielding rye CC was negative up to –50 kg N ha⁻¹ at three site/years and varied around zero for the other CCs except vetch, for which Neff was positive. At SB autumn-harvest, Neff was negative up to –100 kg N ha⁻¹ except for vetch in one trial. SY was lowest after rye CC. Regression analyses indicated a negative impact of CC biomass, C:N ratio and the difference in SMN between fallow (high SMN) and CCs (low SMN) on Neff. To conclude, if CCs yield a high amount of biomass surviving until spring and thus remove SMN from the soil which otherwise remains available for SB, early season mineralization of CC biomass N can be too low to ensure a N supply sufficient for maximum SB yield. Choosing leguminous CCs or early termination of CCs might alleviate this constraint.

Lentils are a good dietary source of essential minerals for the proper functioning of the human body. We evaluated 34 cultivars and elite lentil lines representing the breadth of the Canadian breeding program. Trials were established in 10 site-years across Saskatchewan. Concentrations of 27 minerals were quantified with an inductive coupled argon plasma emission spectrometer in whole and dehulled lentil seeds. Lithium (Li), vanadium (V), chromium (Cr), cobalt (Co), arsenic (As), silver (Ag), cadmium (Cd), tin (Sn), lanthanum (La), mercury (Hg), and lead (Pb) had concentrations below the quantification limit and were excluded from further analysis. The effects of site year, tissue type (whole and dehulled), and lentil genotypes were analyzed using a mixed model. Mineral concentrations of iron (Fe), zinc (Zn), magnesium (Mg), sodium (Na), potassium (K), phosphorus (P), sulfur (S), manganese (Mn), copper (Cu), molybdenum (Mo), boron (B), nickel (Ni), selenium (Se), aluminum (Al), and barium (Ba) was different among genotypes and across environments. Most minerals except Cu had significantly different concentrations between whole and dehulled seeds. Ca, Fe, Mg, Mn, B, Al, and Ba were more concentrated in whole seeds, while K, S, and Ni were higher in dehulled seeds. Among the 34 genotypes, CDC Impala had the highest Fe, Zn, K, P, S, and Cu concentrations. Lentil genotypes with a higher composition of several minerals could be a starting point for enhancing mineral composition in lentils.

The performance of cropping systems is a function of crop and management practice interaction in a given growing environment. However, the critical factors affecting productivity remains unclear under varying climate conditions. We conducted a 5 year study at six sites in western Canada to identify the critical factors affecting the productivity, standardized as protein-based yield (PBY), and quantify the relationships between yield and critical factors. We tested six crop rotations, including conventional system (Control), pulse- or oilseed-intensified system (Intensified), diversified system (Diversified), market-driven system (Market-driven), high-risk and potentially high reward system (High-risk), and soil-health enhanced system (Soil-health). The importance index and structural equation modeling were used to identify key factors and explore the underlying relationships among them. Results showed that Market-driven and Diversified rotations outperformed the Control by 2%–6% in PBY, while Soil-health and High-risk yielded 23%–26% lower than the Control. Relative to the Control, all rotations showed an increase trend in PBY over time, with Diversified rotations increasing 13%–28% faster than Market-driven and Intensified rotations. Precipitation and nitrogen (N) management are the primary factors affecting cropping system productivity, explaining 25% and 21% yield variations, respectively. Structural equation modeling analysis revealed that precipitation had a significant indirect effect on yield through affecting biological N fixation of pulse crops, in addition to a significant direct effect. Increasing pulse frequency and rotation complexity mitigated PBY loss by 10%–24% during low rainfall seasons. We recommend integrating pulse crops into cropping systems to enhance N management and mitigate yield loss in low precipitation regions.

Plant mitochondrial (mt) genomes enable better understanding of cellular processes and phylogenetic relationships. Tea-scented China rose ‘Hume's Blush Tea-scented China’ is the ancestor of the modern hybrid tea rose and has had an important and lasting influence on the breeding of the modern horticultural rose, but a comprehensive description of its mt genome is not yet available. In this study, mature leaves were used to determine the sequence of the rose mt genome. The mt genome of ‘Hume's Blush Tea-scented China’ is a circular sequence 277 730 bp in length and includes 30 protein-coding genes, 19 tRNA genes, and 3 rRNA genes. We analyzed repeat sequences, codon preferences, and RNA editing processes. In addition, we detected the transfer of 25 chloroplast genes to the mt genome, indicating intracellular genes transferred frequently from chloroplasts to mitochondria in ‘Hume's Blush Tea-scented China’. The phylogenetic analysis of the ‘Hume's Blush Tea-scented China’ mt genome and those of 26 other plant groups reflects its taxonomic status. The Ka/Ks of most genes was less than 1, indicating that most coding genes underwent negative selection, while pi was greater than 0.01, confirming highly diverse genetic variation. This work lays a foundation for future investigation of genetic variation in ‘Hume's Blush Tea-scented China’.

Winter canola production in eastern Canada is a growing segment of the Canadian canola industry. Crop establishment and survival overwinter have been identified as two of the major challenges associated with the production of winter canola. Environmental conditions can interact with agronomic practices, including seeding date, plant population density, fertility, and residue management, to influence stand establishment in autumn and overwinter survival. The objective of the current research was to evaluate the impact and interaction of preceding crop residue and tillage practices on the establishment, overwinter survival, and yield of winter canola in southern Ontario. Winter canola was seeded following either winter wheat or soybean and using conventional, no-till, or strip-till practices. Over the course of the 3 years of study, the annual decline in winter canola plant population density was influenced by the type of tillage practice used but not by the preceding crop. The overwinter decrease in plant population density was largest in no-till, followed by strip-till, and finally conventional tillage. At physiological maturity, winter canola yields in reduced tillage practices (i.e., no-till and strip-till) were equivalent to those achieved utilizing conventional tillage practices. When grain yields were standardized as a function of the spring plant population density, the highest and lowest yield per plant coincided with the lowest and highest plant population densities and were observed in strip-till (14.2 g plant⁻¹⁾ and no-till (9.1 g plant⁻¹), respectively. Results of this research have established that winter canola can be successfully produced in Ontario utilizing a range of tillage practices.

From the early days of agricultural production in the 1800s through to the present day, farmers, agronomists, and other motivated people have worked to improve crop production through pest management and surveillance, selection of crop genotypes and agronomic innovations such as reduced and zero-tillage. These essential contributions also helped raise awareness of the practical problems that farmers have faced, of the potential solutions to those problems, and the problems that remain to be solved. In many cases, farmers have organized their efforts to support research to address agricultural challenges through commodity organizations who actively fund research, raise awareness of science, and encourage participation in activities such as pest monitoring and on-farm research trials. This review highlights some of the important contributions of Canadian community scientists. The future of a biovigilance approach to crop production depends on the continued participation of agricultural community members.

Ascochyta blight, caused by Ascochyta rabiei, is a serious constraint to chickpea production, managed primarily via foliar fungicides and genetic resistance. Imidazolinone (IMI) herbicides, used for in-crop weed management, can injure susceptible chickpea cultivars and so increase ascochyta risk. The impact of IMI application on susceptible and tolerant cultivars was assessed in combination with blight management options (starting fungicide application prior to symptom development, two versus four fungicide applications, genetic resistance) in small plot trials in Saskatchewan in 2019, 2021, and 2022. Two kabuli-type chickpea cultivars (CDC Orion, CDC Orkney) and two desi-types (CDC Vanguard, CDC Cory) were grown with or without IMI herbicide. CDC Orion and CDC Vanguard were susceptible to IMI herbicides, CDC Orkney and CDC Cory were tolerant. The severity of ascochyta blight (0–9 scale) was very low in 2019 and 2021 (1.3 in 2019, 0.5 in 2021) and generally did not differ among treatments. In 2022, the desi cultivars had less disease at the end of the season than kabuli cultivars (mean 3.1 vs. 4.3). In 2022, two applications of fungicide (starting before or after symptoms appeared) reduced severity relative to the control (3.5 vs. 4.6). Four applications did not provide additional reduction. IMI herbicides resulted in <15% injury on IMI-susceptible and none on IMI-tolerant cultivars. Waiting for ascochyta symptoms, rated 1, to apply fungicide was just as effective as applying fungicide before symptom development. Fungicides provide yield and disease management benefits when disease is moderate, but not when weather is hot and dry.

AAC Hassler (PT496) is an early maturing, high yielding, awned, and hollow stemmed Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) cultivar suited to growing conditions in the northern Canadian Prairies. AAC Hassler yielded 8% more than Glenn, 6% more than Parata, and 6% more than Carberry in the Parkland Wheat Registration Trials (2019–2021). AAC Hassler matured 4 days earlier than Carberry and had similar maturity as Parata. AAC Hassler had similar height to Glenn and the lodging score was similar to Parata. The test weight of AAC Hassler was 2% lower than the mean of the checks and the thousand kernel weight was similar to Glenn. AAC Hassler had protein content 0.1% higher than Carberry. AAC Hassler expressed an intermediate resistant reaction to Fusarium head blight (FHB; Fusarium graminearum Schwabe). AAC Hassler was moderately resistant to the prevalent races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn) and moderately susceptible to common bunt (Tilletia caries (DC) Tul. & C. Tul.). It was resistant to prevalent races of leaf rust (Puccinia triticina Erikss.) and stripe rust (Puccinia striiformis Westend). AAC Hassler was susceptible to orange wheat blossom midge (Sitodiplosis mosellana Géhin). AAC Hassler was registered under the CWRS class.

AAC Dutton (BW1094) is a hollow-stemmed, awned, and high yielding Canada Western Red Spring (CWRS) wheat cultivar suited to the growing conditions of Western Canada. AAC Dutton was 1% higher yielding than AAC Viewfield, the highest yielding check in the Central Bread Wheat Cooperative registration trials (2019–2021). Within the same test, AAC Dutton was 10% higher yielding than Carberry. AAC Dutton matured 1 day earlier than Glenn, Carberry, and AAC Viewfield and less than a day later than Unity: Unity being the earliest maturing check in the registration trial. AAC Dutton was 10 cm shorter than Unity with lodging score lower than the mean of the checks. The test weight of AAC Dutton was similar to Unity while the 1000-kernel weight was higher than AAC Viewfield. The grain protein content of AAC Dutton was lower than all the checks. AAC Dutton had a moderately resistant reaction to Fusarium head blight (Fusarium graminearum Schwabe) and stripe rust (Puccinia striiformis Westend). AAC Dutton had optimal resistance to leaf rust (Puccinia triticina Erikss.), stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn), common bunt (Tilletia caries [DC] Tul. & C. Tul.), and to orange blossom wheat midge (Sitodiplosis mosellana Géhin). AAC Dutton was registered under the CWRS class.

AAC Stockton is a hulled two-row spring general purpose barley (Hordeum vulgare L.) cultivar widely adapted to western Canada. It was developed from the cross TR11219/CDC Kindersley made in 2012, and it was evaluated in the Western Cooperative Two-row Barley Registration Test (2020–2021) before being registered in 2023. AAC Stockton will offer a good production choice for barley growers across the Prairies due to its grain yield potential, lodging resistance, and improved Fusarium head blight resistance.

AAC Darby (PT495) is an early maturing, high yielding, awned and hollow stemmed Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) cultivar suited to the growing conditions in the northern Canadian Prairies. AAC Darby was higher yielding than all the check varieties in the Parkland Wheat Cooperative (Park C) registration trials (2018–2020). AAC Darby was 6% higher yielding than Parata and 5% higher yielding than Carberry. AAC Darby matured 5 days earlier than Carberry and 1 day earlier than Parata. AAC Darby was similar in height to Glenn at 2 cm taller. The lodging score for AAC Darby was similar to the mean of the checks. The test weight of AAC Darby was similar to Carberry and the 1000-kernel weight was similar to Glenn and higher than Parata. AAC Darby had protein content only 0.07% lower than Carberry. AAC Darby expressed an intermediate resistant reaction to Fusarium head blight (FHB; Fusarium graminearum Schwabe). AAC Darby was moderately resistant to the prevalent races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn) and moderately susceptible to common bunt [Tilletia caries (DC) Tul. & C. Tul.]. It was resistant to prevalent races of leaf rust (Puccinia triticina Erikss.) and stripe rust (Puccinia striiformis Westend). AAC Darby was resistant to orange wheat blossom midge (OBWM) (Sitodiplosis mosellana Géhin). AAC Darby was registered under the CWRS class.

Soybean (Glycine max (L.) Merr.) production in Manitoba has increased substantially over the last 20 years, raising questions about phosphorus (P) fertilization in this region. Between 2013 and 2015, a study was conducted across 28 sites in Manitoba to evaluate the effect of P fertilizer rate and placement on soybean plant stand and seed yield. Treatments were 22.5, 45, and 90 kg P2O5 ha⁻¹ applied as monoammonium phosphate, seed-placed, side-banded or broadcast, plus an unfertilized control treatment. Plant stand reduction due to seed-placed fertilizer toxicity was observed at five of 28 site-years, typically at the rate of 90 kg P2O5 ha⁻¹. Stand reduction was most frequent on medium- to coarse-textured soils, dry soils or when seeding equipment had low seedbed utilization. Seed yield was reduced at two site-years due to seed placing 90 kg P2O5 ha⁻¹, which reduced plant stands below the recommended threshold of 247 000 plants ha⁻¹. Phosphorus fertilization did not increase seed yield, regardless of P rate, P placement, or Olsen soil test P level, except for one site-year where 45 and 90 kg P2O5 ha⁻¹ increased seed yield by 343 and 430 kg ha⁻¹, respectively. The extremely infrequent response to P fertilizer in combination with the high rate of P removal indicates that soybeans can use soil P reservoirs that are less available to other crops. Nevertheless, soybean growers in Manitoba should consider strategies for applying supplemental P to soybean or other crops in their rotation to maintain P fertility in soil.

Three multiyear studies were conducted in Manitoba, Canada to evaluate the effect of nitrogen (N) fertilizer rate (ranging from 0 to 225 or 0 to 240 kg N ha⁻¹) and its interactions with timing of N application (preplant, split application), cultivar (Russet Burbank (RB), Glacier Fryer (GF), Umatilla Russet (UR)), and moisture regime (irrigated, nonirrigated) on the yield and net revenue (NR) of potato (Solanum tuberosum L.). Based on soil test N, all sites were expected to be N-responsive, with soil test N at most sites ranging from 24 to 45 kg NO3-N ha⁻¹ to 60 cm and measuring 70 and 117 kg NO3-N ha⁻¹ to 60 cm at the remaining two sites. Linear and quadratic coefficients of N and irrigation were significant for yield and NR. However, the NR curves for N inputs were relatively flat, and the NRs were only slightly less than the optimal NR within the vicinity of the optimum. Split N applications performed similarly to preplant N, and GF performed better than RB or UR; however, GF optimal economic N rates were about 55% higher than the optimal economic N rates of RB and UR cultivars. Optimal economic N rate for the best potato practices ranged from 157 to 216 kg N ha⁻¹, depending on the studies; or averaging at about 188 kg N ha⁻¹. Adoption of these best N management practices will improve profitability and N use efficiency in potato production and reduce negative environmental impacts.

In Saskatchewan, red clover (Trifolium pratense L.) is often grown for seed production. However, there is no recognized or data supported seeding rate for seed production of red clover in Saskatchwan. The objectives of this study were to identify an optimal seeding rate for seed production and biological nitrogen fixation (BNF) and to examine their relationships under semi-arid conditions. This experiment was conducted under field conditions using six different seeding rates (0.5, 2.5, 4.5, 6.5, 8.5, and 10.5 kg ha⁻¹) at Melfort and Clavet, SK in 2018 and 2019, and seed yield, biomass, plant density, and BNF were measured. In our study, red clover was able to compensate for the range of seeding rates between 2.5 and 10.5 kg ha⁻¹ without seed yield loss and BNF reduction, whereas biomass production and BNF were higher at 4.5 kg ha⁻¹ seeding rate than in 0.5 kg ha⁻¹ at Melfort, but no seeding rate effects were found at Clavet. Regardless of location, biomass was always positively correlated with BNF. However, no association was found between seed yield and BNF. Our results suggest that 4.5 kg ha⁻¹ is ideal for seed production, BNF and biomass production of red clover in Saskatchewan.

AAC GN963 is a high yielding great northern dry bean (Phaseolus vulgaris L.) cultivar with an upright, indeterminate bush (Type II) growth habit, early maturity, and a large seed size. Lodging resistance of AAC GN963 is slight improvement compared to AAC Whitehorse, a great northern bean cultivar with predominant commercial acres under irrigation in southern Alberta. The canning and cooking quality attributes of AAC GN963 were similar to the check cultivars AAC Whitehorse and Resolute. AAC GN963 is well suited for commercial production under irrigation in Alberta and Saskatchewan.