Plant breeding could offer solutions to some of the challenges facing oilseed rape growers. Teresa Rush reports on one business’ approach.
Without doubt oilseed rape is a crop in need of some solutions. Establishment challenges, mounting pest and disease problems, environmental issues linked to pesticides, price volatility, climate change effects – the list seems to keep on growing.
Not surprisingly perhaps, given the combined pressures of resistance, legislation and development costs in the agchem sector, many are looking to plant breeding to deliver solutions – and it appears to be rising to the challenge.
DSV is currently working on a range of technical solutions aimed at improving the durability and consistency of oilseed rape production.
These include companion cropping – already familiar to some growers in the UK – alternative spraying technologies and grass undersowing.
Cropping oilseed rape in a mix with lentils, clover or beans, for example, can deliver a number of benefits but there are also drawbacks, says DSV.
The benefits include introduction of N into the system and a reduction in use of mineral N fertilisers. Companion plants can have weed-suppressing effects and may permit a reduction in herbicide use. They can also have a pest-repelling effect, as well as positive effects on soil structure.
There are, however, some downsides, including effect of companion plants on OSR drilling date, cost, restriction on herbicide use and crop competition.
Dr Doring said: “You need to sow 10 days before your normal [OSR] sowing date to give the companion varieties time to establish. But this can be an issue for oilseed rape; there is a risk of stem elongation before winter due to higher competition and so a higher risk of winter kill.
“You need to match varieties and crop conditions.”
DSV, along with other companies in Germany, is investigating the use of dropleg sprayers to reduce the risk of insecticide spray residues in pollen.
The technique, which enables crop protection products to be applied below the flowering canopy, has particular relevance where insecticides are applied during flowering for cabbage seed weevil control along with sclerotinia fungicides.
Trials are said to have shown positive results in terms of limiting weevil damage and controlling sclerotinia, with no negative impact on yield compared with spray application via a conventional nozzle. There are, however, time and cost considerations, said Dr Doring.
Grass undersowing of oilseed rape is being investigated as a means of limiting nitrogen losses to water.
The grass is spring-sown and could be applied in mixture with slurry, said Dr Doring.
“In water-sensitive areas the integration of a cover crop after rape or rape with an undersown grass crop can be an efficient way to reduce nitrate leaching, especially in autumn and winter,” he said.
The technique is not, however, yet in commercial use and there are issues with following herbicide use – propyzamide (Kerb) – for example, which need to be addressed.
At a technical briefing in Germany recently, DSV international oilseed rape manager Alexander Doring explained how the company, which has been breeding oilseed rape since the late-1960s, is adapting its breeding efforts in response to the challenges of modern oilseed rape production.
DSV is calling its approach PNN – ‘post neonicotinoids’. PNN has two pillars: changes to breeding strategy with a focus on achieving improvements in plant architecture, pest and disease resistance and crop profit and technical approaches – seeking new agronomy and engineering solutions.
Within its breeding strategy, the company has identified four key plant attributes: ‘primary response’ (speed of establishment), optimum pod presentation, performance stability and solar capture, which it sees as key to better oilseed rape varieties.
Varieties with superior primary response characteristics will respond almost instantly once drilled, said Dr Doring.
“This primary response is specifically developed to make the plant establish quickly, driving down a strong taproot so the plant can keep growing through the critical early stages as well as laying down the foundations for optimal yield later.
“This powerful growth habit also helps the crop grow through early pest and disease attack.”
DSV’s first PNN variety, the hybrid winter oilseed rape Dariot, is currently a 2017/18 candidate variety in AHDB Recommended List trials in the UK.
The second attribute is optimum pod presentation, which said DSV, is about enabling a plant to produce the optimum number of pods, even in poor conditions.
“A key attribute of PNN varieties is reduced apical dominance,’ said Dr Doring, “which means more energy and nutrients go into flower and pod production than outright plant growth.”
Performance stability focuses on delivering consistent performance across a wide range of current growing conditions. The aim is also to equip varieties with the ability to cope with the wider range of climatic conditions anticipated in the future, which in Europe is predicted to mean higher rainfall in winter and less in summer.
And lastly, solar capture can be enhanced often through a proliferation of a large number of smaller leaves, without the risk of plants becoming too bulky.
“This PNN feature provides varieties such as Dariot with improved nitrogen efficiency,” maintained Dr Doring.