The revival in world wheat prices this week reflects a weakening in longstanding rumours of an imminent splurge of Russian grain exports, besides the revived appetite among investors for commodities.

Comments by Vladimir Putin, the Russian prime minister, that "crop results must convince us that we fully satisfy our internal necessities" before the country lifts its export ban have muffled speculation of the release of cut-price wheat onto the world market.

"Rumours about potential Russian exports have settled down," Agritel, the Paris-based consultancy, said, citing Mr Putin's intervention.

A London trader told Agrimoney.com: "I have certainly not heard much about it this week. The market seems to have moved on, for now anyway."

Export rumours 

Last week, traders blamed a slide in grain prices was blamed in part to talk that up to 10m tonnes of Russian wheat exports were waiting to come onto the market as soon as the country's grain export ban is lifted at the end of next month.

Exports at that level would represent more than half Russia's annual pace of wheat shipments before drought devastated its harvest last year

However, many parts of western Russia escaped the worst of the drought, sparking talk of hefty grain stocks which need to be shifted to make room for the next harvest.

And SovEcon, the influential analysis group, has reported a build up in grain inventories by merchants awaiting the lifting of the curbs.

'Veritable tidal wave'

A major European commodities group reported on Friday that "what's really worrying traders is the fact that internal Russian prices are some $100 a tonne below world values at present", adding that the "estimates of the surpluses left to move are rising daily".

"One hardly dares to contemplate the effect of 10m tonnes descending on the world market in July," the briefing added.

"What's more, at about the same time, Romanian and Bulgarian new crop wheat will be coming on stream adding to a veritable tidal wave of cheap wheat emanating from the Black Sea."

In addition, merchants in Ukraine were also preparing to lift exports, following plans to replace export quotas with duties.

'Calm and balanced'

Mr Putin said that a decision on grain exports would be taken "calmly and in a balanced manner", with Russians needing to "be certain that our domestic needs are met completely" before shipments are permitted.

Shipment of 10m tonnes would require supplies from the forthcoming harvest, with the country forecast by the US Department of Agriculture to end next month with inventories of only 2.3m tonnes.

Some analysts have proposed that Russia - which has voiced a desire to repair its reputation with import customers forced to turn elsewhere by the export ban - might allow limited exports, of perhaps 2m-3m tonnes, through quotas from July.

Rabobank analysts said on Wednesday said they deemed an imminent return by Russia to shipments as "unlikely", given "production uncertainties", but added that "given normal weather... it is likely that exports resume, in some capacity, but more likely in the third or even fourth quarter" of 2011.