Poor OSR pod set sparks unease

29 June 2001



Poor OSR pod set sparks unease

By Andrew Swallow

REPORTS of poor pod-set in Gemini oilseed rape are prompting questions about the varietys pollination success this year.

Near total yield loss is expected in a number of crops of the varietal association hybrid. The full extent of the problem across the UK is not yet known.

Breeder CPB Twyford blames sulphur deficiency, but others question the flowering co-ordination of the component lines.

“Sulphur deficiency will affect the fertilisation and pollination even if the crop does not show visual symptoms,” says CPB Twyford director Theo Labuda.

In the 50 plus crops checked so far by CPB there is a huge range in symptoms, he says.

“Some crops are fantastic, others have a loss of pods but not to the extent we would expect to see any yield loss.

In a number of crops the podding is absolutely awful. In most cases that is where sulphur was not applied, or applied too late.”

But Masstocks David Neale believes that pollination problems go beyond sulphur deficiency.

“i have seen one field of Pronto which is fabulous, and next to it Gemini that has bare branches.”

Both had received the same inputs, so sulphur shortage is unlikely to be the cause, he says.

Reports of late flushes of flowering in some Gemini crops suggest trouble with the synchronisation of flowering between the male sterile line and the pollinator, Artus, he adds.

Mr Labuda says that can be ruled out. But he acknowledges that there are question marks over the establishment or survival of the pollinator in some crops.

NIAB reports that, even if lack of pollination does result in fewer pods and seed set, yield may not suffer due to compensation in seed size.

CPB Twyford says concerned growers should contact their agronomist or seed merchant in the first instance.

• Welsh GM worries block hybrid seeds, FWi, 18 June, 2001
• Call for three-year OSR variety tests, FWi, 24 May, 2001
• High yields from petal-free OSR, FWi, 18 June, 2001