Variety choice could explain variation in oilseed rape yields

Performance in line with the five-year average hides wide variability in oilseed rape yields. Oilseed rape yields this summer have been highly variable, but several varieties have demonstrated remarkable consistency.

“Across the country yields have been reasonable, albeit with a few poor crops,” says Openfield national seeds and technical manager Lee Bennett.  “But while final performance is likely to mark a slight gain in overall output we have not seen the outstanding yields expected before harvest,” he adds.

The reasons for this, he believes, largely comes down to the growing season and variety choice.

“The crop sat with wet feet all winter with no or few frosts. It then got away early in the spring drawing on mineral nitrogen reserves to produce a large canopy before growers had opportunity to apply fertiliser. It is possible that the applied N went on too late in some cases.

Lee Bennett

Lee Bennett

“The forward nature of the crop continued into flowering starting and finishing early to leave an unusually long grain fill period which didn’t quite live up to its purpose, perhaps because the crop had exhausted its nutrient reserves,” he says.

The mild weather also favoured disease, which will have impaired performance in some cases.

“Varieties with only moderate disease scores have had a tough year. In particular, Verticillium wilt has spelled the end for a couple of varieties,” he says.

CONSISTENT VARIETIES

The less-than-perfect season may be partly responsible for the variable performance, but variety choice too has been a decisive factor, suggests Lee Bennett.

“Across eight trial sites and 30 varieties we have seen huge variability between varieties, but also within varieties. Only four varieties have been consistently good performers, but apart from one, they make up only a small percentage of the national crop.

“For several years and across all sites from Yorkshire to the Cotswolds and to East Anglia, our most dependable variety has been DK Extrovert and it is again this year with a gross output of between 4.8-5.8t/ha.

“Similarly, Trinity and Popular have both produced consistent performances which has been reflected in sales of commercial seed on farm,” he says.

A pleasant surprise has been the performance of V316OL, a high oleic, low linoleic variety and a candidate for the 2015-16 HGCA Recommended List.

“The yield penalties once associated with HOLL varieties are clearly behind us with the introduction of V316OL. At the Somerset, Cornwall, Wiltshire and Gloucestershire sites it out-performed all others with a gross output ranging from 4.5-5.9t/ha.”

The performance of V316OL mirrors that seen in official HGCA trials where it tops the East and West results list with a 2014 mean gross output of 116% of controls while Popular is second with a gross output of 110%.

 

About Openfield

·         Openfield is the UK’s leading farmer-owned grain marketing business handling around 4.6mt of grain every year.

·         Openfield is owned by 2700 farmers who commit grain to the business and also works with over 4000 others.

·         Openfield markets over 1mt of grain for the Openfield Network central storage member companies every year.

·         Openfield is also one of the largest suppliers of seed and fertilisers to UK farmers.

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