Objective:                  

To identify the optimum planting dates and varieties of winter canola to ensure winter survival and high yield potential in Northwest Montana

Personnel:                 

Clint Beiermann, Jessica Pavelka                

Summary:

Six varieties of winter canola were planted at three planting dates: August 15th, September 1st, and September 15th of 2021. They were irrigated in the establishment year to establish a stand, then received only rainfed moisture, and were harvested on August 16th of 2022 (Table 1).

Yield was affected by planting date and canola variety. Canola planted on August 15 and Sep 1 yielded 61.1 bu/A and 70.3 bu/A, respectively, outyielding canola planted September 15 at 41.0 bu/A. The highest yielding variety was Mercedes, planted on 1st planting date at 77.9 bu/A, with seven other varieties being statistically equivalent within the August 15th and September 1st planting dates (Table 2, Figure 2). Between the August 15th and September 1st planting dates, Photosyntech Quartz, Rubisco Mercedes, and Rubisco PluraxCL were all within the top yielding varieties (Table 2).

Oil content is generally high for all varieties planted in the study, with oil content values ranging from 45.2% up to 48.2%. Oil content was affected by variety and closely reflects seed yield, with Rubisco Mercedes having the highest oil content at 48.2% (Table 3).

Canola survival rate during the overwinter period was affected by planting date. Canola planted on August 15th experienced a 20% stand reduction while September 1st had a stand reduction of 31%. However, Canola planted on September 15th resulted in significantly poorer survival with a 78.8% stand reduction observed during the overwintering period (Table 4).

Based on two seasons of results, planting dates between August 15th to September 1st would be optimum to establish winter canola in northwestern Montana. Repeated years of research on this study will strengthen results.

 

Table 1. Management information
Seeding date: 8/20, 9/3, 9/21 Field Location: Y7
Julian date: 232, 246, 264 Harvest date: 8/16/2022
Seeding rate: 18.4 plants/ft2 Julian date: 228
Previous crop: Fallow Soil type: Silty Clay Loam
Herbicide: None Tillage: Conventional
Insecticide: Lambda-CY 5/24/22

Soil residual nutrient

(NO3-1, P, K lb/A):

 167-12-143-72S
Fungicide: None

Nutrient fertilizer applied

(N, P2O5, K20 lb/A):

 Applied Spring 2022 100-42-37-20S

 

Table 2. Agronomic performance of the winter canola varieties based on planting date
Planting Date Yield (bu/A) Variety Survival % Yield (bu/A)
    CP1022WC 94.8 58.7
    CP225WRR 82.5 50.8
15-Aug 61.1 CP320WRR 94.0 59.3
    Photosyntech Quartz 74.5 64.9
    Rubisco Mercedes 90.5 68.4
    Rubisco PluraxCL 83.0 64.4
    CP1022WC 77.5 64.3
    CP225WRR 79.3 62.0
1-Sep 70.3 CP320WRR 82.0 72.1
    Photosyntech Quartz 76.3 68.5
    Rubisco Mercedes 87.5 77.9
    Rubisco PluraxCL 80.8 76.8
    CP1022WC 6.3 7.9
    CP225WRR 21.0 50.7
15-Sep 41 CP320WRR 26.8 63.3
    Photosyntech Quartz 4.3 5.9
    Rubisco Mercedes 24.0 41.3
    Rubisco PluraxCL 33.0 76.9
CV 35.6   12.46 19.02
LSD 14.45   11.02 15.56
Mean 57.47   62.1 57.47
PR>F <.0001   0.003 <.0001

 

 

Table 3. Oil content by variety
Variety Oil (%)
Rubisco Mercedes 48.2
Rubisco PluraxCL 47.9
Photosyntech Quartz 47.5
CP1022WC 46.5
CP320WRR 45.3
CP225WRR 45.2
CV 2
Mean 46.7
PR>F <.0001

Bold = top performer;

Bolding denotes equal value to highest or earliest

value within a column based on LSD(0.05)

 

Table 4. Stand reduction by planting date
Treatment Fall Stand Spring Stand % Stand Reduction
  plants/m2 plants/m2  
15-Aug 132.6 103.9* a 20.00 b
1-Sep 143.6 96.6 a 31.00 b
15-Sep 124.3 26.0 b 78.82 a
*Treatments denoted by different letters are significantly different at α=0.05

 

Bar chart of winter canola yield by planting date

Figure 1. Winter canola yield by planting date