Oilseed rape review Vigour is priority


for oilseed rape • Establish crops early for best results • Manage with nutrient and regulators • Consider yield, gross output and disease


S


electing oilseed rape varieties that


estab-


lish quickly and out- grow pest and disease threats should be a priority this year, farmers are being told. From cabbage stem flea beetle in hotspot areas to slugs and pi- geons almost anywhere, oilseed rape often faces a tough start. It is a challenge made harder with the loss of neonicotinoid seed treat- ments – so getting crops drilled and away quickly is vital. Sowing vigorous varieties ear- ly can trigger worries about thick, forward canopies that can lodge later. But Hutchinsons nation- al seeds manager David Bouch says it is better to be in this situ- ation – and manage it with nutri- tion and growth regulators – than have poorly established crops. Semi-dwarf varieties, such as


DK Secret, could help mitigate these concers in early-drilling slots, says Mr Bouch. They ben- efit from the strong autumn vig- our of hybrids, but produce short- er, stiffer canopies less prone to


Choice of varieties


Architect • High-yielding hybrid with good gross output


• Resistant to Turnip Yellows Virus


• Stiff stems reduce lodging risk


• Winter hardy • Vigorous autumn and spring growth


• Pod shatter resistance • RL suggests lower gross output in north • Later flowering


24 ANGLIA FARMER • JULY 2018


Campus • Consistent • Gross output just 2% off top performers


• Conventional open- pollinated variety, so can home-save seed if desired


• Good all-round disease scores reduce risk


• Vigorous autumn establishment


• Suits early drilling • No major weaknesses


DK Expedient (east & west) • Exceptional autumn and spring vigour


• Good resistance to phoma and light leaf spot


• Pod shatter resistance • No major weaknesses


Anastasia (north) • Conventional variety that consistently performs well in northern areas


• Suits early drilling • High resistance to LLS (7) • Strong, stiff variety • Can be one of the first to sell out


lodging. Semi-dwarfs can also mean quicker harvesting.


Risk mitigation With unpredictable disease pressures – notably phoma and light leaf spot, Mr Bouch urges growers to select a mixed portfo- lio of varieties with different ag- ronomics to spread risk and po- tentially ease crop management through the season. “Light leaf spot has tradition- ally been the priority in the north, but we’ve seen it in the south of the UK too. So much depends on the season. In some years pho- ma is a bigger concern, so it pays to mitigate against this risk un- certainty by growing a range of varieties.” Yield, gross output and dis-


ease scores remain key factors when assessing varieties. But


“


It pays to mitigate against uncertainty by growing a mix of varieties.


Getting rape crops away early can help fend off pests and disease


Phoma and light leaf spot are a concern – David Bouch (left)


Mr Bouch says growers should also carefully consider autumn and spring vigour, drilling date, maturity and resistance to pests or diseases.


Erucic acid levels


The increasing popularity of her- bicide-tolerant Clearfield varie- ties could see more growers in- clude them in cropping plans – especially if European policy- makers proceed with proposals to tighten limits for erucic acid levels in oils and fats destined for the food industry.


This would see the current


erucic acid limit in “00” varie- ties cut from 5% to 2% and has prompted concerns that more growers may be penalised or have loads rejected. “The benefit to the final price you receive can far out- weigh any yield penalty associ- ated with growing a CL variety.” Major sources of erucic acid contamination are thought to in- clude volunteer High Erucic Acid Rape (HEAR) and weeds such as charlock, wild radish, and mus- tard. Better control of these is- sues using the Clearfield system could have important benefits for growers supplying food markets.


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