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Vigour is Top Priority for Oilseed Rape Choices

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Selecting oilseed rape varieties that can establish quickly and outgrow pest and disease threats should be the priority when planning 2018/19 seed orders, according to leading agronomy firm Hutchinsons.

From cabbage stem flea beetle in hotspot areas of the southeast, to slugs and pigeons almost anywhere, oilseed rape often faces a tough start in the autumn. It is a challenge made harder with the loss of neonicotinoid seed treatments, so getting crops drilled and away quickly is vital, says the firm’s national seeds manager David Bouch.

He acknowledges that sowing vigorous varieties early often raises concerns about generating thick, forward canopies that are more prone to lodging later in the season, but insists it is far better to be in this situation, which can be be managed with nutrition and growth regulators, than have poor establishment.

Select OSR varieties on their ability to get up and away in the spring

Semi-dwarf varieties, such as DK Secret, could be one way of mitigating these concerns in early-drilling slots (e.g. beginning of August in southeast England), he suggests. They benefit from the strong autumn vigour of hybrids, but produce shorter, stiffer canopies that are less prone to lodging. Semi-dwarfs can also help reduce combining time, he notes.

Risk Mitigation

With unpredictable disease pressures, notably phoma and light leaf spot, Mr Bouch urges growers to select a mixed portfolio of varieties with different agronomics to spread risk and potentially ease crop management through the season.

“Light leaf spot has traditionally 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 phoma is a bigger concern, so it pays to mitigate against this risk uncertainty by growing a range of varieties.”

Yield/ gross output and disease scores remain key factors when assessing varieties, but alongside autumn and spring vigour, drilling date, maturity and resistance to pests or diseases should also be considered carefully.

Mr Bouch also highlights the increasing popularity of herbicide-tolerant Clearfield varieties and suggests more growers may include them in cropping plans if European policymakers 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” varieties cut from 5% to 2% and has prompted concerns that more growers may be penalised or have loads rejected.

Volunteer High Erucic Acid Rape (HEAR) and certain weeds (charlock, wild radish, and mustard) are thought to be major sources of erucic acid contamination, so better control of these issues through the Clearfield system could have important benefits for growers supplying food markets.

“The benefit to the final price you receive can far outweigh any yield penalty associated with growing a CL variety.”

Mr Bouch picks out some other varieties to consider, as summarised below:

Variety/ suitable region

Strengths

Weaknesses

Architect

(all regions)

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

Campus

(all regions)

Consistent in all regions

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 & 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