FARMERS are being warned to take account of the fact that seeds will be smaller than normal this year due to the drought during pod fill, when sowing this back-end.

They should go for bigger seeds where possible, particularly where there are establishment challenges, according to Clive Sutton, at DLF Seeds.

“Bolder seeds are proven to boost vigour at germination due to the extra energy they contain. This means crops can grow away from disease and pest challenges for more even establishment,” he said, pointing to trial results at the Saskatoon Research Centre, in Saskatchewan, Canada.

These had shown that leaf area, shoot weight and biomass of seedlings from large canola seeds were 1.3-2 times greater under controlled conditions than those from small seeds. In field conditions without insecticides, seedlings from small seeds had the highest flea beetle damage, poorest establishment, and lowest shoot weight, biomass and yield, said the report.

Seedlings from large seeds were more vigorous and tolerant to flea beetle damage and this was put down to a higher initial shoot biomass and higher growth rate.

“At the Cereals Event this year, Anglia Grain Services had a display of smaller seeded plants growing next to larger seeded ones and the difference was really noticeable,” pointed out Mr Sutton. “You could see the difference in rooting and both the cotyledons, and first leaves were markedly bigger.”

One advantage of using conventional varieties rather than hybrids is that it is relatively cheap and easy to increase seed rates to account for local weather and pest conditions, he added. " But, when farm saving seed, it is vital to get it properly dressed to obtain bold seeds with no admixture. It’s also worthwhile choosing varieties that naturally have larger seeds through their superior genetics – Broadway and Elevation, both new to the Recommended List this year, were specifically bred for large pods, seed content and seed size.”

DLF's conventional, Broadway, has so far being one of the star performers in the current harvest. With just one site left to be harvested, Elevation is top of the table, scoring 106% of the control mean seed yield – with impressive results from Scotland to the south coast.

Although only placed on the RL for the North, the variety has proven its suitability to be grown right across the country, with yields of 108% in both Fife and Hampshire. “It is also consistent, having had the highest gross output in northern trials in 2017, at 107.4%, and scoring well in the east-west trials, at 102%,” said Mr Sutton.

The variety benefits from good stem disease tolerance, which has helped against verticillium wilt and canker, which have been a particular problem this year. It also has bigger seeds and Mr Sutton added: “Plants with larger pods, bolder seeds and more seeds per pod have a natural advantage when it comes to yield. Every 1g extra in thousand seed weight at harvest gives you an extra 15-20% yield for the same seed number.”