Cereal growers concerned that breeders may be coming up against a genetic barrier to yields just when the world needs them boosting most can take heart.

“Over 60 years yield improvement has continued on a pretty steady basis,” said NIAB statistician Ian Mackay. The average in the mid-1940s was about 2.5t/ha – today it was about 8t/ha, he said.

Presenting the interim results of a new analysis co-funded with BSPB, Dr Mackay showed how 90% of the increases in the yield of winter wheat and winter and spring barley in the past 25 years were down to breeding.

That contrasted with an earlier study which estimated that from 1947-1978 only about half the yield lifts in wheat, barley and oats came that way, the other half arising from better agronomy by way of fertilisers, pesticides and machinery.

The latest study used modern computer methods not available to the first, conducted by NIAB’s Valerie Silvey.

But a key finding in the latest work was that there was as much genetic variance showing up in today’s trials as in those of the earlier era.

“Because there’s as much variance entering the trials system today, it doesn’t seem to me that the fuel that’s driving improvement is running out,” said Dr Mackay.

Clearly, national yields had seemingly “plateaued” since the mid-1990s, but that could be due to many factors, not least the economic pressure on growers to cut costs and so not fully exploit the full genetic potential of new varieties, he acknowledged.

Inputs such as fungicides and fertilisers still had vital roles’ without them yields would be on average 2t/ha lower, he said.