Mr Iwaniw, who will retire at the end of this week, said with AWB losing the single desk, no single entity now represented the industry.

"AWB developed some fantastic brand names, but who is going to promote that today? That's a real challenge for the industry," he told the Australian Grains Conference in Melbourne.

There were many important issues facing the industry, such as carbon trading, but "there is no single voice to talk about that".

Hand in hand with that was the greatly diminished role of the state grain farmer organisations, which was "very sad".

Under deregulation and privatisation, ABB Grain has become the dominant listed agribusiness company, but Mr Iwaniw said he regretted the demise of the single desk.

The single desk had benefited most farmers, although he acknowledged it was better for some.

The demise of the single desk had been largely caused by the industry itself, through early problems at the NSW Grains Board, culminating in the AWB Iraqi oil-for-food scandal.

Mr Iwaniw said deregulation had created a "challenging environment", with multiple buyers and potential exporters.

There had been a big increase in growers warehousing grain so growers now carried the price risk, and pools had become less popular as cash took on a bigger role.

But he said there would still be a role for niche markets.

Mr Iwaniw said price volatility had increased, and AWB's share of bulk exports had fallen from 100 per cent to about 20 per cent.

"Logistics is going to become very important. When people buy grain, they will have to take into account the difficulty in getting that product to market," he said, taking into account things such as the big penalties payable if chartered ships were not filled.

Mr Iwaniw said the scheme booklet detailing Viterra's takeover bid for ABB Grain should be made public either tomorrow or Friday.

People did not understand the complexities of mergers and acquisitions.

"Unlike a marriage, you can't get divorced," he said.