THE yield spread between spring linseed varieties (87-107) on the Descriptive List is larger than for oilseed rape. But with NIAB warning against reading too much into differences of less than 8%, it should pay to look to other characters to help choose suitable types.
The continued presence of 1990 introduction and top yielder Blue Chip (107) on the list when it no longer figures in the seed statistics proves the point, says Mr Kightley. "You cannot ignore it as it has had a very favourable run of seasons to do well. But we know it is late and that is not whats wanted. It has a big potential for serious lodging." Sharpes says only very limited amounts of seed remain.
Three varieties account for about 60% of the seed area – Barbara (102), Antares (97) and Flanders (91).
"Antares is clinging on to its popularity partly because it does not attract royalties. There are numerous maintainers so seed is relatively cheap. But it has also been tremendously reliable for establishment. But Barbara is higher yielding and very popular."
Growers putting earliness ahead of all other criteria should consider Flanders or possibly Norlin (90), both rated 7, suggests Mr Kightley. All other varieties, bar Mikael (97) on 6, merit scores of 5 or less.
"Of the two I would certainly go for Flanders. Norlin is early maturing but very late flowering." In dry years this can limit its seed filling potential, he explains.
Mikaels shortness, matched only by the lower yielding Abby (95), Linda (89) and Bolas (89), is attractive for easing harvest. "The beauty of it is that it is very easy to combine as you tend not to get any wrapping. Thats a problem that catches growers out every year."
Of the newer varieties, Zoltan (104) is an "improved Barbara" with slightly higher oil content. At 105 this years addition, Jupiter, has the yield edge to offset its slightly lower oil so making it of equal value to growers, says Mr Kightley.
Choice for the contract edible oil market is expanded with the addition of variety 989 which matches Windermere (96) for yield. But its oil content is 1.6% lower.
• Turn to page 42 for details of choices in peas and beans.