While varietal traits such as vigour, yield and disease resistance are rightly high on the agenda when assessing and choosing OSR varieties, oil content is often overlooked. However oil bonuses are becoming increasingly important in the profitability of winter OSR and should be one of the starting points when choosing a new variety, he says.

“At 1.5% of the “double low” contract price for every 1% over 40% oil, oil bonuses on £270/tonne base price can still bring in an extra £96.7/ha at 4t/ha for a crop over the 46% level.”

“Oil content is a stable trait in a variety so is a fairly guaranteed return and the overall premium only increases with yield, so its money in the bank.

“There are few if any ways to boost the oil content of a variety agronomically. On the other hand late-flowering applications of foliar nitrogen can reduce oil content but this is generally off-set by higher seed yields.“

The 14 most popular ‘double low’ varieties, which account for about 70% of national planting, vary quite widely in their oil contents and therefore potential oil bonus, Mr Leaper notes.

“Looking at the AHDB oil bonus official trials data, Charger which is one of the top ten varieties in terms of seed yield at 107% of the controls, does not do so well on oil bonus for only offering 43.9% oil content and a resulting bonus of £85/ha.

“Campus, although a poorer yielder at 104% of the controls, does a bit better with an oil content of 45.3% bringing in a bonus of £112/ha, which means that there is not actually much difference between the varieties in terms of gross output.”

“The conventional variety Nikita at 108% seed yield has one of the highest oil contents on the recommended list at 45.6% and therefore tops the AHDB official trials for both the east/west and north regions for oil bonus payment, bringing in an extra £129/ha and £118/ha, respectively.

This makes a big difference to the overall gross output of the variety and puts it right at the top in terms of profitability.

“It has been recognised for many years that oil contents are generally lower as you go further north, which is why Nikita has a slightly lower bonus in the north than in the east/west – but it’s still the top variety on the RL countrywide.”