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Genetic improvements are bringing better disease resistance to oilseed rape varities – helping to make the crop easier to grow. How better genetics are improving oilseed rape

• Disease resistance delivers results

• Higher yields and stronger growth

• Benefits throughout whole season

Genetic improvements are bringing better disease resistance to oilseed rape varities – helping to make the crop easier to grow.

Improved genetics are focusing on keeping rape stems healthy – creating varieties with better resistance to phoma, light leaf spot and verticillium, says Chris Guest, managing director of LS Plant Breeding (LSPB).

“Phoma resistance has taken a major step forward,” says Mr Guest.

Progress includes the launch of RlmS – a new genetic trait by LSPB – in 2021. Four LSPB varieties with the RlmS trait – Murray, Vegas, Flemming and Respect – are on the AHDB Recommended List (RL) with seed available to growers now.

Different background

“They provide an important complementary resistance to Rlm7, which has been the mainstay for some years,” explains Mr Guest. “RlmS has a different genetic background – an adult stem-based resistance – unlike Rlm7, which acts on the cotyledons.

RlmS resistance is also associated with strong overall plant health, adds Mr Guest. The gene has good stem resistance – an additional benefit against late season disease, he says.

“We will bring further varieties with RlmS resistance – some already in trials and others in the pipeline – to complement Rlm7 and give longevity of phoma resistance to growers.”

Autumn trash

Light leaf spot infection comes from autumn trash. After a latent period of two to three months, it is most damaging in the spring, producing stem and pod infection with most sources quoting a significant potential yield loss of about 1t/ha.

There are three major gene resistances. Each has a different mechanism to stop initial infections, to stop conidial production and cycling and to reduce overall growth.

Recommended list ratings have shown a steady upward trend with LSPB Turing at the top of the RL for the UK in both East/West and North regions.

Turing scores 7 for light leaf spot, closely followed by Vegas  (8) and Murray in the East/West region (7), explains Mr Guest.

“There is a strong correlation between yield and light leaf spot resistance – and as such this should be a key focus for growers thinking of oilseed rape for harvest 2024.”

Significant impact

Verticillium also has a significant impact on yield with loss figures of 12-24% quoted in one AHDB study. But LSPB trials suggest yield losses may be even greater than is currently recognised – as seen during harvest 2021 and harvest 2022.

Results from a single location should be viewed with caution. But they suggest Turing, Murray and Fleming have verticillium resistance,  yielding some 6.4t/ha – some 10% more than less resistant varities.