After several challenging years, OSR is becoming a crop easily overlooked by many growers but with a potentially much reduced threat of CSFB, strong rotational benefits and the best genetics ever at their disposal, is it time for a rethink?
While OSR has been a risky choice in the rotation in recent years, it's still a farmer's favourite with indications of a rising level of confidence in the crop, believes Agrii arable seed specialist David Leaper.
Many growers like what OSR offers in terms it being a broad-leaved crop, its earliness of harvest and the fact that it helps them get a timely wheat crop in behind it, but there are many other benefits, he says.
"That early harvest also helps with managing summer workloads and you can ship it off farm fairly early leaving storage for your wheat, plus it's a crop we're all familiar with and there is a considerable amount of OSR knowledge out there.
"But it's been a risky option of late due to increasingly challenging weather and the rise in cabbage stem flea beetles (CSFB) problems following the neo-nicotinoid ban. It's front-loaded nature, from an investment point of view, doesn't help either.
"We've found there is no one solution to the problem, so schemes like the industry's 'Reboot' initiative is really helping focus on priorities and Agrii's eight point OSR plan has always been popular with our customers.
"Risk-share schemes, where growers can get all or part of money back on seed if the crop fails in the autumn, have also helped but they are only a partial solution as they do not cover the larval stage the following spring."
Diminishing threat
The CSFB threat is now diminishing, however, as less of the crop is grown and rotations lengthen from a historical one in every three years to often one in seven in the rotation now, he points out.
"We definitely haven't seen as much CSFB on-farm this last year as previous years and we are probably starting to see the benefits of the life cycle of the pest dissipating across the reduced acreage.
"Whereas before we could have seen 60 - 80 larvae per plant, it's now down to two or three, often in the petioles and this is no longer causing the catastrophic populations we have seen. In truth, it is probably a sustainable level we can live with.
"Many growers were certainly reassured last year when they did not see the same levels of adult beetles in the harvested crop as they had previously."
David Leaper, therefore, advises growers to keep open minded mind and be prepared to be opportunistic when it comes to the crop this year.
"If fields are cleared, they are ready to go and if there is moisture in the soil, then I would choose a strong, fast growing variety and be prepared to give it a go.
"Numerous trials have shown early developing varieties that are able to cope with difficult establishment conditions and grow away quickly in the autumn cope best with CSFB. Good vigour in the spring also helps avoid problems at the larval stage.
"This is very much the case with lower levels of CSFB on plants that we are seeing now. A well-developed plant with a big crown and large leaves covering the ground is also very effective at minimising damage from pigeons, too."
Ironically, as the UK OSR area reaches its lowest point for some years, varieties are at their absolute best, with growers increasingly focused on consistency of performance rather than the last decimal point of performance, he points out.
"The breeders have put a phenomenal amount of work into stacking traits, bringing all these different diseases resistances together and improving physical properties such as standing."
Crop resilience key
Sarah Hawthorne of breeders DSV, says resilience of varieties has been a key breeding priority for many years with the company's post neo-nicotinoid (PNN) initiative underlining this.
"PNN put the emphasis on what was needed in a variety to mitigate against the loss of neo-nicotinoids with much of this around the all-important vigour, plant architecture and ability to grow through pest and disease threats.
"Such properties underpin much of our current OSR range with hybrid breeding absolutely at the heart of this, as it allows us to develop stronger varieties, more able to thrive in challenging conditions than we could with conventional breeding.
“Our trials have in fact shown DSV hybrids consistently produce 15% more root mass than conventional varieties and not only does this help anchor plants, it gives them much greater resistance to abiotic stress and leads to higher GAI and improved photosynthetic potential."
The company continues to invest in advanced oilseed rape genetics to build real-world resilience with its latest Phoma Blocker, CRE1 enhanced clubroot protection and Powerful Pods clear indications of this, she points out
"DSV's Phoma Blocker trait, for example, features a resistance mechanism for phoma stem canker completely new to Europe and is already featured in our new varieties Cognac and Dompteur with other varieties currently going through UK testing.
"The technology adds a much-required additional layer of security for the future by the addition of LepR1 or RlmS to the widely used Rlm7 resistance.
"Whilst LepR1 by itself has been shown to have the best resistance to the most common phoma strains in field trials across Europe, we believe it is most effective when used in conjunction with other disease resistance traits.
"DSV now uniquely has varieties featuring all three different phoma resistance mechanisms - Rlm7, RlmS and now LepR1 - that can be rotated in the field to minimise major breakdown of any one type of resistance."
Improved field performance
In recent years, DSV's clubroot protection has also played an important role in keeping spread of the disease in check and also protecting yields for growers, she adds.
"DSV has been particularly successful in this area with varieties such as DSV Crocodile CR offering good protection without yields being compromised, which has usually been the case before such varieties were introduced.
"We have now introduced a new clubroot resistance mechanism called CRE1 (Clubroot Resistance Enhanced 1) with a broader protection against more pathotypes and this is already available in the new DSV variety Cromputer CR."
New oilseed rape genetics have also been developed by DSV to improve harvest performance by building on traditional pod shatter characteristics, she explains.
"Our latest RL addition DSV Dolphin is the first of a new generation of hybrid varieties specifically developed to combine a key set of genetic traits to protect them against adverse weather conditions later in the season.
"All of these developments add to the future viability of oilseed rape and allow growers to have greater faith in the crop and its ability to deliver high margins."