WOSR - a key crop for 2023 and the important varietal traits to look for!
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The profitability of crops has changed dramatically in the past year, with increased costs and increased commodity prices raising the stakes of growing any crop. Therefore, it is important to have a spread of crops that either drill earlier, grow at different stages or ripen at different times to help reduce risk on your farm.
In Seedtech, we have identified crops that offer growers an opportunity to save on nitrogen (N+ ADVANTAGE), and these crops need serious consideration this autumn and next spring. With that in mind, the case for growing winter oilseed rape (WOSR) in autumn 2022 is strong, and farmers need a good reason not to drill it.
In Ireland, we grow some of the highest yielding WOSR crops in the world (YIELD SECURE), and at current forward prices, WOSR is a very attractive crop (SUSTAINABLE CROP). There is also the added security of forward trading of oilseed rape which needs to be balanced with input prices and discussed with your merchant.
Finally, WOSR offers growers an opportunity to significantly save nitrogen in spring 2023 (see more on GAI and canopy management below) and brings all the benefits of a break crop.
Hybrid WOSR varieties, such as AURELIA, have really made growing this crop most reliable and profitable on-farm.
Key reasons to grow WOSR
It is profitable based on current forward prices
The only crop you can drill in August, so it gets a job done in good conditions
The only crop that can utilise the valuable nitrogen in autumn applied organic manures
Only crop to absorb and use the 25% of yearly sunshine that falls in August, September and October
Offers huge nitrogen savings in spring using GAI and canopy management
Leaves soil suitable for direct drilling a cereal after harvesting
Saving Nitrogen in spring 2023 using Canopy Management (N+ ADVANTAGE)
The system of canopy management works on the principle that a dense crop of rape contains more nitrogen (taken up over winter) than a thin crop. WOSR is the only autumn-sown crop that can take up nitrogen over the autumn and winter, adding it to sunshine and storing it (as green leaf and stem) to reduce fertiliser N in Spring 2023.
Remember - 25% of Ireland’s annual sunshine occurs in August to October and only WOSR can absorb this sunshine and make use of it the following spring.
The measurement is called the Green Area Index (GAI), and each score of GAI score = 50 kg N/ha (40 units per ac) is very valuable at current fertiliser prices.
The crop can be assessed (by eye, smartphone app or by weighing it) in springtime, and based on the GAI score, it is possible to save €100 per acre on the average crop of WOSR in spring.
Most WOSR crops reach a Green Area Index of 2 which can save 100 kg N/ha) using the Teagasc canopy management research.
Calculating GAI for spring applied nitrogen requirements in WOSR
Using GAI and canopy management with John Sprink Teagasc and Tim O'Donovan, Seedtech
Benefits of Winter Oilseed Rape and the financial benefits of using the GAI App (Green Area Index) to save on nitrogen in winter oilseed rape.
WOSR crop and the effect of radiation on N requirements
De-risking oilseed rape with modern varieties (YIELD SECURE)
Modern plant breeding has made great strides in WOSR varieties and has de-risked rape for growers and the whole industry.
Figure 1 Pod Shatter trait on left, no pod shatter on right
Prior to pod shatter resistance being bred into rape, rape was liable to suffer huge losses coming up to harvest. Breeders have worked hard to reduce the risk of pre-harvest losses and modern varieties such as AURELIA and LG AVIRON have excellent pod shatter genes (see figure 1)
While we all know about BYDV in barley, little is known here about Turnip Mosaic Virus in rape.
Recent testing of crops in Ireland has confirmed the presence of this virus and the best way to secure yield is to grow a resistant variety (see figure 2)
AURELIA and LG AVIRON are both resistant to this virus so another thing less to worry about. This virus is spread by the same aphid that spread beet yellows so the presence of one virus is often an indication of the other.
Lastly, we know a delayed harvest can really upset oilseed rape drilling plans. However, LG AVIRON is a real option to drill late and certainly is suitable to be drilled up to mid-September in southern sites*
Where charlock and other brassica weeds are an issue, Clearfield rape varieties offer a fantastic solution. These Clearfield are varieties like BEATRIX CL are tolerant to a herbicide (Cleranda) that will kill charlock and other brassica weeds (and non-Clearfield oilseed rape varieties). See pictures of a Clearfield rape variety and how good the Cleranda is to control charlock and other brassica weeds, photo taken 4 weeks apart.
*Consult your IASIS registered agronomist for specific drilling advice for your situation
Figure 2 WOSR leaf with Turnip Yellows virus symptoms
Figure 3 Brassica weeds before Cleranda applied
Figure 4 Brassica weed-free crop
Trait-stacking in hybrid oilseed rape. What genetic traits are important when choosing a winter oilseed rape variety?
Seedtech prioritise the selection of WOSR hybrid varieties with excellent disease resistance traits - light leaf spot (LLS), TuYV and pod shatter resistance.
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The three key varietal attributes needed for a reliable and profitable WOSR crop on farm are:
1. Disease resistance (Aurelia: score 8; highest Light Leaf Spot (LLS) resistance on DAFM RL 2022)
2. Excellent Lodging Resistance (Aurelia: score 8 on DAFM RL 2022)
3. Pod shatter resistance traits (Aurelia: score 8; Seedtech Trials 2021)
Liam Wilkinson, LG discusses what genetic traits are important when choosing which variety to sow this autumn
LLS resistance helps prevent yield-robbing and early spring infection
LLS is the most yield robbing disease in Ireland (especially in Cork and southern counties) as our wet winters rapidly spread the spores through the canopy.
The current advice is spray at first sign of disease (previously this advice was spray when 25% of plants were infected at beginning of stem extension). Fungicides are best applied before infection, which is almost impossible to achieve practically, as infection often occurs from autumn right throughout winter and into spring.
Having a variety with good LLS resistance (such as AURELIA; 8 on DAFM 2022 list) helps reduce and slow down infection cycles, buying you time from autumn fungicides until fungicides can be applied again in the spring.
During grain fill (in May and June), LLS lesions can be seen on the stems and branches of varieties with weaker LLS resistance. At this stage LLS reduces the efficiency of moving water and nutrients to the developing grains and variety resistance is an important characteristic.
Figure 5 LLS lesion visible in April 2022
Figure 6 Close up of LLS lesion ‘salt grains’
Figure 5 Image showing LLS in WOSR stem with AURELIA on left, competitor on right
Figure 6 Close up of LLS lesion on competitor
Aurelia Agronomy Characteristics
Extremely high yielding in DAFM trials 2019, 2020 & 2021
Best Light Leaf Spot (LLS) resistance on DAFM Rec List 2022 (8) - helps prevent yield-robbing and early spring infection
Has super pod shatter resistance
Excellent stem stiffness and harvest security
Rapid autumn growth and hybrid vigor
Has Turnip Mosaic Virus (TuYV) resistance
See more on Aurelia WOSR here
Aurelia is a fully loaded hybrid variety with an outstanding package of genetic traits. Aurelia is an exceptional, very high-yielding hybrid winter oilseed rape variety which shows a consistent performance.
Seedtech's Oilseed Rape Aurelia offers a great package with excellent disease resistance, Light Leaf Spot (LLS), TuYV, and pod shatter resistance.
What are the tangible benefits of sowing oilseed rape and in particular Aurelia WOSR with Clive Cole
Getting the most from WOSR
Modern hybrids can be drilled up to mid-September in good conditions.
Drill 50 seeds/m2 (70 seeds/m2 in September).
Hybrid vigor helps plant establish rapidly and recover from Autumn losses/grazing.
Choose a variety with good Light Leaf Spot resistance on DAFM 2022 list - helps prevent yield-robbing early Spring infection and later infection on stems.
Use GAI canopy management where opportunities arise to save nitrogen.
