Plant establishment

Investigating Tolerance of Canola Genotypes to Heat and Drought Stresses, and Root Traits Estimation by Electrical Capacitance

Principal investigator:

Bao-Luo Ma, AAFC Ottawa

Purpose:

To better understand the physiological
mechanisms of tolerance to heat and drought stresses
in canola genotypes.

Progress:

Drip irrigation systems were shown to increase seed yield by 39 per cent, seed oil content by 4.3 per cent and root capacitance by 66 per cent as compared with the rain-fed practice in a drought-prone year (2016). Measurable differences were found between the genotypes under drought conditions, indicating the feasibility of utilizing root capacitance measurements to quantify canola tolerance to drought stress. A related study found that seed yield and root capacitance were both significantly higher with early planting dates. As well, root capacitance showed strong and positive relationships with seed yield and seed oil content, implying that the electrical capacitance measurements can be used to estimate root morphological traits and potentially predict canola seed yield and seed quality. In addition, an improved non-destructive method was developed for measuring canola root size, and a new method to assess root characteristics and crop lodging was also evaluated.

Canola Sustainability – Risk Mitigation

Principal investigator:

Neil Harker, AAFC Lacombe

Purpose:

To determine if the risks of growing canola more frequently in rotations can be mitigated by inputs that are higher than normal (fertilizer, seed) or unusual practices (enhanced seed treatment or chaff removal).

Progress:

The greatest yields were recorded when canola was grown only once in three years at a normal fertility regime (a peas-wheat-canola rotation). The canola-
wheat-canola rotation yielded similarly. While continuous canola with 50 per cent more fertilizer and 50 per cent more seed yielded similarly to the peas-wheat-canola rotation, extra fertilizer and seed costs would likely make the former treatment less economically viable and more risky from a weed, disease and insect pest point of view. Therefore the cheapest and most consistent method of achieving optimal canola yields is to ensure that there is diversity in the crop rotation sequence.

Canola Rotation Studies

Principal investigator:

Claude Caldwell, Dalhousie University

Purpose:

To gain a better understanding of how canola can fit into existing cropping systems in Eastern Canada, this four-year study was conducted at three locations in Nova Scotia, Ontario and Québec and was based on an established rotation experiment.

Progress:

Crop yields and plant height at harvest were significantly influenced by the crop sequence. Canola yields were greatest when grown after corn and lowest when grown canola on canola. Soybean and wheat yields were also greatest when grown after corn and lowest (for both) when grown after wheat. Although not significant, corn yielded highest when grown after soybean and lowest when grown after wheat.

Fertility management

Variable N fertility management of canola at the field scale, based on analysis of yield maps and spatial and statistical variability of soil test N and P

Principal investigator:

Alan Moulin, AAFC Brandon

Purpose:

To examine the impact of variable rate nitrogen fertility programs on canola yield in areas with consistently high production. It also investigates the economic return and efficiency of fertilizer use, the relationship between canola yield and the variability of canola yield and soil-test nitrogen and phosphorus, and the variability related to soil-test recommendations, among other factors.

Progress:

This study was originally designed for combined analysis of data from 24 sites over three growing seasons and was extended to include sites in the 2017 growing season as well. Preliminary results showed considerable variability in the soil and crop data collected from sites, significant differences in yield monitor data between farms, and significant contrasts between a nitrogen rate of 0 and rates of 50, 100 and 150 per cent of soil-test recommendations for several farms in partition analysis. Preliminary findings from 2016 show that spring soil-test P averaged for all fields was similar to previous years, and showed a trend to higher P in lower-producing zones.

Integrated pest management

Characterization and development of new resistant sources for sustainable management of clubroot in Canola

Principal investigator:

Gary Peng, AAFC Saskatoon

Purpose:

This project, which builds on previously identified clubroot resistance (CR) genotypes, discovers new CR genes with novel traits, develops markers closely linked to these CR genes (to assist CR breeding) and investigates resistance mechanisms by different CR genes for better deployment of these CR genes.

Progress:

In addition to publishing four peer-reviewed papers in 2016, the collaborative efforts of AAFC Saskatoon, University of Alberta and University of Manitoba carried out genetic mapping of additional CR Brassica rapa lines. This resulted in the discovery of two new CR genes that have promise against pathotype 5x and further work made it possible to successfully generate B. napus carrying both of the CR genes. Utilizing sequencing technology, researchers also figured out a way to transfer different clubroot resistance genes from B. rapa into canola through marker-assisted selection. CR genes at different locations on the chromosome may have similar resistance modes of actions and this study has proved the value of separating CR genes or gene combinations based on their modes of action against different pathotypes.

Management of clubroot in a dynamic environment

Principal investigators:

Sheau-Fang Hwang, Alberta Agriculture and Forestry, and Steven Strelkov,
University of Alberta

Purpose:

The aim is to develop effective and economical techniques to eradicate localized clubroot infestations using soil fumigants, to assess the impact of cropping rotations which include clubroot-resistant (CR) canola cultivars and to optimize practices for disinfecting agricultural and industrial equipment that has been contaminated with clubroot-infected plant material and/or soil containing spores.

Progress:

Vapam fumigant application was found to reduce clubroot severity at 40-80 mL/m2. Some residual toxicity to the plants was noted at higher dosage rates. Vapam treatment was most effective when sealed under plastic for 12 days, but sufficient ventilation time (1-2 weeks) must be allowed afterwards before seeding to avoid residual toxicity. Disease severity tended to decline when CR cultivars were rotated, but alternating non-hosts, resistant cultivars or fallow with susceptible cultivars did not reduce disease, nor did growing the same CR cultivar over repeated cycles. Although resistance breakdown is an ongoing challenge to clubroot management, differentiation between cultivars in the degree of resistance breakdown will provide opportunities for the study of how host and pathogen genetics interact.

Clubroot surveillance and epidemiology

Principal investigator:

Stephen Strelkov, University of Alberta

Purpose:

To utilize clubroot surveillance to track incidence and predict the spread of clubroot, identify potential issues, monitor populations for pathotype shifts, and evaluate clubroot resistance in fields, which can support all other clubroot-related research and management activities.

Progress:

The 2016 survey of 570 commercial canola crops in 40 counties and municipalities in central and southern Alberta revealed 68 new fields with clubroot (Plasmodiophora brassicae Woronin) infestation. Disease severity ranged from mild to severe, with an average index of disease of <10 per cent in 45 crops, 10-60 per cent in 20 crops, and >60 per cent in three crops. The three cases of severe clubroot were found in susceptible hybrids. The grand total of clubroot-infested fields confirmed in Alberta since surveys began in 2003 is now up to 2,443. While most of the 289 new cases were found on susceptible canola hybrids or hybrids of unknown resistance, 42 fields planted to clubroot-resistant hybrids had symptoms of the disease.

Development of Pest Management Decision-making Protocols for the Swede Midge in Canola

Principal investigator:

Rebecca H. Hallett, University of Guelph

Purpose:

To evaluate efficacy and timing of insecticide applications, the use of pheromone-based action thresholds and to develop decision-making protocols for the timing of insecticide applications in order to reduce swede midge damage in spring canola.

Progress:

The application of regression analyses to the pooled data from trials conducted on grower fields (in 2013-2015) has helped to explain the relationship between swede midge pressure (represented by male midge counts in pheromone traps) and yield. These analyses, combined with results of previously reported lab studies, have led to the recognition that yield impacts to canola may result from lower swede midge pressure than previously thought, indicating that a lower action threshold may be needed for canola than has been evaluated to date.

The environmental footprint of canola and canola-based products

Principal investigator:

Vern Baron, AAFC Lacombe

Purpose:

To estimate farm-gate canola carbon footprints in each soil zone and the greenhouse gas intensity for canola production using best management practices in a high-yielding, high-input region.

Progress:

Canola production had an economic advantage over barley, considering five-year average production costs and gross revenues produced net revenues of $302 per hectare for barley and $783 for canola. Carbon is gained during the growing season and lost outside of the growing season, during dormancy and at harvest (removed in the form of grain). Carbon yield in grain was greater in early-planted canola than late-planted canola. Carbon dioxide (CO₂) emissions from farming activities were largely from manufacturing farm inputs (78 per cent) and diesel fuel used in farm operations (19 per cent). Nitrous oxide emission was 51 per cent greater for early-planted canola than early planted barley due to higher amounts of N fertilizer used and higher contribution of N (from residue) to the soil for canola (vs barley). Therefore, the average carbon balance for all crops and planting dates was negative. The amount of carbon assimilated in net production by the crop environment offset the emissions from nitrous oxide and CO₂ from farming operations and activities but did not when the amount of carbon removed from fields in grain was accounted for.

Operational models to forecast canola growth stage, sclerotinia risk, and yield in Western Canada

Principal investigator:

Rishi Burlakoti, Weather Innovations

Purpose:

To develop models and deploy forecasting tools for canola growth stage, sclerotinia stem rot risk and canola yield on a near real-time basis.

Progress:

Three years of small-plot trials and field-scale trials were utilized to create canola growth-stage predictions for short-, mid-, and long-season cultivars with accumulated physiological day (P-day) thresholds. Sclerotinia biology and disease knowledge combined with a previously developed sclerotinia stem rot (SSR) checklist made it possible to develop a SSR score card and model (with weather and agronomic parameters as input variables). The score card was validated using field data and the SSR model will be refined using field data to be collected during the 2017 cropping season. A custom webpage (canoladst.ca) is being used to collect and record field trial data as well as deploy and validate model prototypes. When completed, this SSR risk model will provide site-specific advisories for growth-stage predictions and sclerotinia stem rot risk in Manitoba, Saskatchewan and Alberta to help producers with fungicide treatment decisions and agronomic activities.