Canola variety by time of sowing, Binnu 2015 trial report

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This trial investigated better matching canola varieties in the northern agricultural region to sowing time to see if yields could be increased. This included comparing the response of common RoundupReady (RR) and triazine tolerant (TT) varieties to different times of sowing.


  • Early sowing is the key to maximising canola yield in the northern agricultural region.
  • All varieties yielded less when sown on 29 April compared to 14 April.
  • Yield loss was on average 43kg/ha per day between 14 April and 29 April sowing.
  • Using the highest yielding variety rather than trying to match variety maturity to sowing date was the best option.

Background and aim

In 2013 and 2014 dry winter conditions resulted in early sown canola crops becoming drought stressed. Some farmers and agronomists in the northern region reported better yields from later sowing dates. The question was asked, are we matching our canola varieties to sowing time as well as we can do?

The aims of the trial were to see if matching canola variety maturity to sowing time would increase yields and to compare the response of common RoundupReady (RR) and triazine tolerant (TT) varieties to different times of sowing.

Trial details

The trial was conducted at the Northern Agri Group Trial site north east of Binnu. Plots were 18m long by 1.54m wide. The trial was designed such that TT and RR plots were blocked. Within these blocks varieties were randomised. There were four replicates of each treatment. Measurements included plant density, plant biomass in late winter and also at plant maturity, seed yield and seed quality.


Treatments included 10 varieties (five TT and five RR) and two sowing times (TOS) (14 and 29 April).

The varieties included a range of season lengths: CB Telfer (very early), ATR Stingray (early), ATR Bonito (early/mid), Hyola 450TT (mid), Hyola 559TT (mid/late), Pioneer 43Y23 RR (early), Hyola 404RR (early/mid), GT41 (early/mid), GT50 (mid), Hyola 525 RT (mid).


Rainfall at the site exceeded the long term average for Binnu of 340mm (Table 1). 160.2mm of rain was received from January to 11 April, prior to sowing. The first time of sowing treatments were sown on soil moisture from over 40mm received from 7-11 April. The temperature at sowing was close to 30°C causing the soil to dry rapidly. Time of sowing two was sown on 29 April on marginal moisture. Long periods without rain occurred throughout winter: 12 April to 17 May (1.2mm), 19 May to 16 June (3.6mm) and 22 June to 20 July (1.6mm).

Table 1 2015 Rainfall at Binnu (mm)
Site Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Binnu 6.0 15.4 103.0 41.8 32.0 53.2 89.4 21.8 5.4 0.0 - - 373.4

Plant density was much lower than the targeted 20 plants/m2;. This occurred because the conditions at seeding and following seeding were hot and dry. Averaged over all treatments there were eight plants/m2. While establishment varied from 5-11 plants/m2 there was no statistically significant difference between plant density at TOS 1 and 2 or between varieties.

Table 2 Plant density (plants/m2)
TOS / Variety 43Y23 Bonito CB Telfer GT 41 GT 50 Hyola 404RR Hyola 450TT Hyola 525RT Hyola 559TT Stingray
1 9.0 7.7 7.2 7.0 7.4 7.9 8.1 8.4 7.2 5.0
2 8.7 9.4 9.5 5.5 6.7 7.5 10.9 9.5 10.1 8.4

When measured on 18 August dry matter production was significantly greater from the first time of sowing. Averaged over all varieties TOS 1 produced 145% of the biomass of TOS 2. The RR herbicide types produced on average 128% the biomass of the triazine herbicide tolerant varieties at this time. There was also a significant interaction between the herbicide tolerance type and the time of sowing. The RR plants responded more to the early sowing date than the TT types. This resulted in RR biomass production being significantly greater than TT at TOS 1 but not at TOS 2.

The overall yield of the trial was 1322kg/ha. Averaged across all varieties TOS 1 yielded 1647kg/ha compared to 997kg/ha for TOS 2. Hence delaying sowing by 15 days led to 650kg/ha less yield, equivalent to a loss of 43kg/ha/day. There was a variety response with the more recently released hybrids among the highest yielding varieties (Figure 1). There was no significant difference between herbicide type, with RR types yielding on average 1362 and TT types 1282. While there was some variation between the varieties in the amount of yield loss from the later sowing time (Figure 1) statistically the varieties could not be separated for response to sowing time, P = 0.112.

Yield was greater from mid-April than late April sowing as described in text.
Yield was greater from mid-April than late April sowing as described in text

Most varieties produced less oil in the seed from the 29 April sowing compared to the 14 April sowing but there were some exceptions and averaged across all varieties oil content was 44.5% at both sowing times. The varieties did differ in oil content; Hyola 404RR had a high oil content compared to many of the other varieties, which is consistent with previous observations. RR varieties had on average 0.4% more oil in the seed than TT varieties; however this was not statistically significant.

Seed weight was more responsive to the treatments imposed. TOS 1 seed was 114% the weight of TOS 2. There was significant variation among the varieties and the TT plant type had heavier seed than RR plant type.

Total seed costs were calculated using cost per kilo and the seeding rate, which was adjusted for seed size and germination percentage. The lowest cost seed was Telfer at $3/ha, it was assumed that seed of this older variety had been retained on farm. Seed cost of all the hybrid varieties was around $80-100/ha. There was a large range in gross margin from $648-158/ha. The newer hybrid varieties had the highest gross margin. It should be noted that the prices used in this analysis were five year averages; non-GM $523/tonne and GM $543/tonne. It was interesting to note that the newer TT hybrids were very competitive with the top RR varieties. It should also be noted that for all varieties except Telfer we assumed that new seed was brought. Using retained seed of open pollinated varieties; ATR Bonito, ATR Stingray and Telfer would increase gross margins.

Table 3 Seed cost ($/kg), total costs ($/ha), income ($/ha) and gross margin ($/ha)
Variety TOS Seed ($/kg) Seed total ($/ha) Total costs ($/ha) Income ($/ha) Gross margin ($/ha)
Hyola 559 TT 1 $24 $78 $475 $1123 $648
43Y23 1 $32 $94 $482 $1116 $634
Hyola 450 TT 1 $24 $86 $480 $1029 $549
Bonito 1 $13 $47 $435 $932 $497
Hyola 404 RR 1 $32 $83 $463 $949 $485
GT 50 1 $25 $81 $456 $838 $381
Hyola 525 RT 1 $34 $93 $482 $849 $367
Hyola 559 TT 2 $24 $78 $461 $803 $341
Stingray 1 $12 $37 $417 $736 $319
GT 41 1 $32 $103 $477 $752 $275
43Y23 2 $32 $94 $464 $696 $232
Telfer 1 $1 $3 $376 $600 $224
Hyola 404 RR 2 $32 $83 $450 $634 $184
Hyola 450 TT 2 $24 $86 $463 $629 $165
Hyola 525 RT 2 $34 $93 $470 $597 $126
Bonito 2 $13 $47 $419 $530 $111
Telfer 2 $1 $4 $368 $409 $41
GT 50 2 $25 $81 $440 $477 $37
Stingray 2 $12 $37 $401 $360 -$41
GT 41 2 $32 $103 $456 $298 -$158

This trial provides more evidence that early sowing is critical to maximise canola yield in the northern agricultural region. There was little difference between herbicide type and the response of varieties was similar to TOS. This indicates that using the highest yielding variety rather than trying to match variety season length to sowing date was the best option in this trial.


Thanks to Stephanie Boyce, Jo Walker and the Geraldton RSU for trial management and measurements and Nolan Harris and NAG for supplying the site. This trial (15GE44) is part of the Tactical Break Crop Agronomy project (DAW00227), co-funded by Department of Primary Industries and Regional Development and Grains Research and Development Corporation.

Contact information

Martin Harries
+61 (0)8 9956 8553
Mark Seymour
+61 (0)8 9083 1143