Canola is a member of the Brassica family of plants. Developed in the 1970s by Canadian plant scientists, canola has grown to become one of Canada’s most popular and profitable crops. About 40,000 farmers harvest 15.3 million acres of canola in the Canadian Prairies and Southern Ontario every year. Another two million acres are grown annually in the United States.
Canola plants experience growth throughout every stage of production, from planting to harvest. A deep understanding of each stage of development will help you better manage the crop from planting to harvest. Certain fertility decisions are only effective at specific stages of development, and factors like the climate and soil conditions can impact the evolution of growth. Thus, it is important to better understand canola’s growth stages and development cycle to better manage crop production while meeting your goals. Knowing what stage of growth your crops are in will also allow you to better manage their health, assess crop quality, and determine the best time to harvest.
Before canola production begins, the first step in the process is germination. After planting, canola seeds rapidly take up water in moist, oxygen-rich soil until they split, and root tips begin to emerge. This stage typically lasts 4-10 days depending on planting depth, soil temperature, and moisture. After germination, canola crops go through six stages of development, from seedling to ripening. First, the seed is split, and then leaves, stems, flowers, pods, and seeds are developed in a cycle. As the canola crop moves throughout the stages of production, the plant begins to bud and grow.
Each stage of the production process is influenced by soil conditions, weather conditions, and fertilizer and nutrient management decisions. From germination to seed production, the typical canola plant takes about three and a half months to complete the growth cycle.
Click through each of the MORE buttons below to learn more about each stage of canola development to help you make better management decisions this season.
CLOSE X
Heading
Copy
Stage 0 – Germination
Seeds rapidly take on water and must be in contact with moist soil in the presence of oxygen. Seeds swell with water, splitting the seed coat, and the root tip emerges. Canola is sensitive to soil salinity, and germination can be impaired in saline soils. Temperature will also affect seed germination. This stage lasts roughly four to 10 days, depending on planting depth, soil temperature, and moisture.
Stage 1 – Seedling
Seedling roots continue to develop, and leaf development begins. After emergence, the cotyledons open and supply the seedling with energy. The seedling is vulnerable to soil-borne pathogens and flea beetle injury. The canola plant growing point is between two cotyledons, where damage can kill the seedling. As the tap root system expands, secondary roots emerge from the taproot. The first true leaves appear about four to eight days after emergence.
Stage 2 – Rosette
First true leaves begin to expand forming the “rosette”, a cluster of leaves forming around the main stem with older leaves at the base and smaller, younger leaves at the center. The stem has not yet begun to elongate yet continues to grow thicker. Canola growth rate is dependent on sunlight exposure. This stage can be characterized by an increase in leaf area index.
Stage 3 – Bud/Bolting
Bolting (stem elongation) and flower bud development are triggered by lengthening daylight and rising temperatures. Flower buds become visible around the center of the rosette. Secondary branches form from buds and develop in the axils of the upper leaves. The canola plant reaches maximum leaf area index during this stage. Stem elongation overlaps with leaf and flower development. Most of the photosynthesis occurs in the leaves; loss of leaves means potential yield loss.
Stage 4 – Flowering
During flowering, the lowest buds in the main stem begin to open, continuing for 14-21 days. Three to five flowers or more will open per day and 40-55 percent of open flowers will develop pods. During this stage, heat and moisture stress and nutrient deficiencies can cause flowers to abort resulting in potential yield loss. Full plant height is reached at peak flowering.
Stage 5 – Seed Development
Seed development occurs during mid-flowering. The location of the pod will determine the nutrient access and seed size, and number of seeds per pod. During the first couple weeks of seed development, the seed coats expand until the seed is almost full size. Plant stress during this stage can cause pod abortion. When seed expansion is complete, plants will be more resistant to pod and yield loss.
Stage 6 – Ripening
Ripening begins when the petals fall from the last flower and plant leaves begin to yellow. Seeds begin to fill about 35-45 days after flowering begins. When they are fully mature, seeds are yellow. Seeds in the last formed pods are in the last stages of filling when 30-40 percent of the seeds on the main stem of a plant have changed seed coat color. During this stage, the crop is considered ripe and is ready to be swathed when 30-40 percent of the seeds on the main stem have turned brown. If growers are using a contact herbicide to desiccate, the recommended application timing is when 60-70 percent of the seed has turned brown, more than the typical swathing stage.
