Growers’ favourite, DK Extrovert was the best performing of the 35 varieties in 2015/16 Frontier trials at both Haywold in Yorkshire and Alford in east Lincolnshire under very different conditions and establishment regimes.
On Haywold’s free draining flinty clay loam from traditional plough-based establishment the variety’s treated seed yield of 5.78 t/ha was almost a tonne/ha ahead of the trial mean. Combined with the fourth highest oil content of the varieties tested, this produced a gross output of 120% of the trial mean at 6.22 t/ha. And this despite high autumn pressure from cabbage stem flea beetle.
A close second to DK Extrovert and the only other variety with a gross output of more than 6t/ha was V316OL, yielding 5.62t/ha at 46.2% oil. Also well within the top 10 performers was RL candidate, DK Exception with a gross output of 5.65t/ha.
With a seed yield of 5.77 t/ha, this emerging new hybrid was second only to DK Extrovert from min-till establishment on Alford’s much heavier ground. Here, the leading variety at 6.09 t/ha yielded over a tonne more than the trial mean, with oil levels yet to come in.
Drilling on both sites was at the end of the first week in September with nitrogen and SO3 applications of around 240 kg/ha and 100 kg/ha respectively and full fungicide programmes.
More than anything else, these results confirm the pre-eminent output ability DK Extrovert continues to show across a range of conditions and establishment regimes in trials as well as commercial practice. Despite the large number of new varieties coming forward these days, they suggest it will continue to remain a firm grower’s favourite for some time to come.