24 July 1998


AS in cereals, lodging looks set to have a strong impact on winter oilseed rape choice for sowing this year, says NIAB oilseeds specialist Simon Kightley.

Some varieties have shown markedly less resistance to lodging than their ratings predicted, he says. But this partly reflects the growth stage some early flowering types were at when Easter snows and heavy rain hit.

With three hybrids, five fully recommended and eight provisionally recommended conventional types, growers have plenty to choose from.

"People are going to be very keen on standing ability," says Mr Kightley. Until eventually succumbing to one of the worst crop flattening spells for several years, three varieties stood out in trials this season – Apex, Lipton and Lightning. Newcomer Madrigal is another which stayed upright better than its current rating suggests.

It is by no means stiff stemmed, but a certain amount of leaning to produce matted canopies can be an advantage because varieties remaining upright are more vulnerable to pod shatter, he points out.

And some of the ratings for lodging resistance and stem stiffness are bound to change as a result of this seasons experiences.

Overall yield potential, however, cannot be ignored. Apex, in particular, now fully recommended only for the central and southern regions, is slipping. "Its yield is now 8% adrift of the best conventional variety and 13% behind the top hybrid."

That hybrid, fully restored Pronto, stands slightly better than its stablemate Artus, is earlier and has better oil content. "Growers should consider a substantial area of it," suggests Mr Kightley.

Concern about pollination reliability of varietal associations in commercial crops continues to make NIAB cautious about Synergy, but he acknowledges trial yields have been generally high and on a par with fully restored Artus.

Yields of Madrigal, Licrown and Boston – the other new provisional recommendation this year – show conventional varieties still have plenty to offer. "Madrigal is only 5% below the best hybrid," he notes. Licrown is only a couple of points lower. Bostons exceptionally high oil content, the best on the list at 44.8%, puts it slightly ahead of Licrown in value.

Top rated variety with full recommendation is Capitol. But with the poorest listed combination of lodging resistance and stem stiffness, that accolade is confined to the central, south-east and south-west. A very vigorous variety it is best managed using the reduced seed rate advised by breeder Cargill, says Mr Kightley.

Only Alpine is fully recommended for the whole of the UK. With combined lodging resistance and stem stiffness second only to Apex and the now outclassed Express, it is just a point behind Capitol for yield, he notes.

The earliness of Gazelle and Commanche make them particularly appealing to northern growers despite potentially lower output.

Provisionally recommended Herald and Lipton are on a par for yield. But the latter withstood this seasons bad weather better and has higher oil content and slightly more resistance to light leaf spot.

Contact is a point adrift on yield but is early with good resistance to stem canker and above average oil content. "But it was one of the earliest flowering varieties this season and lodged during the Easter storms at some sites, so its lodging score of 7 will be under review."

Lightning and Meteor are provisionally recommended for the central, south-west and south-east only.

Lightning, relatively late and so unsuitable for the north, stood up well this year and could see its lodging resistance score of 7 raised. Its lateness may even be an asset in the south to help spread harvest workloads, Mr Kightley suggests. "It also has the lowest glucosinolate content on the current list.

"Meteor lodged badly at several sites this season and early results must be watched to see how this has affected its performance."

Besides Express, Amber and Falcon are also becoming outclassed.

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