Initial oilseed rape variety trials show a mixture of new and old performing well. Louise Impey reports
Highly variable yields and variety performance are being reported from HCCA’s Recommended List trials harvest results for the East and West region, which are now half way through completion.
Overall, yields are down on previous years at 4.5t/ha, which is a little lower than the four-year average of 4.7t/ha.
But they have ranged from 2.8t/ha up to 6.3t/ha, points out HGCA‘s Jim McVittie, showing how variable oilseed rape can be. “That’s why growers should look at the over-year mean results for any given variety. That’s the figure that matters.”
One site in particular has given some unusual results, he says. “The Lincolnshire site has proved to be low yielding, except where the semi-dwarf varieties are concerned. They’ve done strangely well there.”
The reasons for this aren’t clear yet, he admits. “We’re satisfied that they did achieve this level of performance, but we don’t know why. It’s out of balance with the other sites and may be due to the drought effect.”
It means that this year’s yield figures for some of the semi-dwarf varieties, most notably PR45D05, are influenced heavily by the one site.
“Again, use the over year results. The likes of DK-Sequoia, PR45D05 and DK-Secure are all within 2% of each other.”
In general, the semi-dwarfs are now getting within 4-5% of the best winter varieties, he adds. “It is difficult to compare the two types in a trials programme, but there has been a slow, steady increase in them on farm.”
Of the conventional types, Dr McVittie picks out three current choices – DK Cabernet, Fashion and Vision – as continuing to impress. “They’ve all performed well again, ranging from 106 to 103, putting them in the top six of the conventional choices.”
Three conventional candidates are also showing their promise at this stage, he adds. “Sesame, which has always looked good, has come back a bit this year to 106 and is the second highest yielding winter variety.”
The other two, Oracle and DK-Camella, have performed well in 2010, he notes. “Oracle is a very stiff variety which is now giving yields on a par with DK Cabernet. And DK Camella is maintaining its good yields.”
An old favourite, Es-Astrid, is also yielding well this year, says Dr McVittie. “That’s interesting because it has a particular strength in its canker resistance, but it hasn’t been a bad canker year.”
Of the hybrids, the current highest yielding winter variety on the Recommended List, PR46W21, is holding on to its top spot in 2010 with 107. “It looks as though it will head up the list for another year.”
In contrast, Flash and Dimension are slightly down, at 101 and 100 respectively. “In the case of Dimension, we’re now confirming where it stands, as this is its fifth year in trials. It had a very good year in 2006.”
Excalibur is performing very well this year at 104, he notes. “Growers will be pleased, as it represents 11% of the national crop. Their faith is being rewarded.”
Candidate hybrids which have done well include Palace, Rhino and Primus. “Palace and Primus are much as we expected, while Rhino is having a good year.”
His final mention is for Cracker, the candidate variety with club root resistance. “It’s yielded the same as Mendel in the east and west, but we’re expecting it to do better in the north.”
Growers should be encouraged by the results from DK-Cabernet, although there was no frost or pollen beetle damage seen to the variety in the RL trials, says Dr McVittie.
“There were fears about it earlier on in the season, so it’s reassuring to see that it has done well so far.”
He points out that varieties produce twice as many flowers as they need for optimum pods, which is why late frosts don’t always have a lasting effect.
“But it is the latest to mature, which has been creating harvest issues on some farms.”
Doug Pickup of Sentry Farming in North Norfolk agrees that it was the last of his winter rape varieties to desiccate and harvest, but has been pleased with the results.
“After a very drawn out flowering period, it’s done better than the others. It seems to have amazing powers of recovery and I’m sticking with it.”
• For the latest HGCA variety trials harvest results click here