SPRING oilseed rape growers really cannot afford to ignore the potential of provisionally-recommended hybrids, according to NIABs Simon Kightley.
Even allowing for the extra cost of seed the new types offer useful margins over conventional varieties making them well worth trying, he suggests. "Most of them combine early vigour, early maturity and high yields – the three key requirements in the spring crop." Imports mean there should plenty of seed this season, he adds.
Mr Kightleys only reservation is that the newer hybrids, Concept and the three Hyola varieties, have been trialled over only seasons. Conventional varieties like Maskot and Rebel, recommended in the 1998 list which replaces the purely descriptive list, have been tested for five years, he explains.
"We have had some pretty dry years recently and we want to see how the hybrids perform in the long run over different types of UK summers."
His concern over reliability of performance from varietal associations is far less for spring types than winter. The fact that pollination takes place in high summer suggests there should be less risk of poor seed set.
"Of the two varietal associations on the list, Concept looks the better all round and certainly had a very good trials year in 1997."
Of the fully-restored varieties, Hyola 38 is exceptionally early ripening. At the other end of the scale Triolo, Rebel, Licosmos and provisionally recommended Liaison, which at 22% occupied the biggest share of the seed area, are all relatively late. Earliest of the conventionals is Acrobat.
Best conventional yielder, by a whisker, is newly listed Canyon. But Mr Kightley calculates the top hybrids crop values should be £25-30/ha higher. "I understand the seed price of the hybrids will be in the order of £15/ha which still leaves a good extra margin."
Compared with other similarly yielding conventional types, Liaison just has the edge on oil content at 43.1%. But best of all for oil, including the hybrids, is fully recommended conventional Licosmos on 43.6%. "Superol is slightly down at 41.6%," notes Mr Kightley.
Other conventional names with a significant share of the seed area include Aries and the now outclassed Starlight, the variety which signalled the big surge in breeders improvements to the crop, he says.
Three varieties, Barbara, Antares and Flanders, continue to dominate the certified seed area with a 60% share between them and yield ratings respectively of 102, 96 and 95. But a trio of new names, Geria, Agristar and Flechette, offer potentially better yields (106, 105 & 103), as does last years addition to the descriptive list, Jupiter (105).
Geria is marginally ahead on output. "But after only three years trials I wouldnt want to make too much of that difference," says Mr Kightley. But of the three it is also the earliest, he notes.
"Flechette is on the late side which could be a bit of a worry for growers on heavy land."
Standing power of the three newcomers is effectively the reverse of their maturity scores.
The fourth newcomer Moonraker (96) is as short as Mikael (100), Abby (95) and Bolas (92). But as with peas shortness is not necessarily an advantage, especially on light drought-prone soils, notes Mr Kightley.
Windermere is the highest yielding linola outstripping the later Coniston by about 6% and having marginally better oil content. Variety 989 is almost on a par for yield but has nearly 2% less oil.
High-yielding hybrid rapes could make linseed appear less attractive as a spring break in the future.
Yield ratings of recommended oilseed rapes
100Aries, Marinka, Star
98Acrobat, Licosmos, Sprinter
Hybrid (varietal assoc):
Hybrid (fully restored):
107 Hyola 38
98 Mars, Melodi, Solar