GENEVA - The Black Sea grain deal allowing seaborne exports from Ukraine will most likely be renewed, market sources say, but even a veto by Russia would not stop Ukrainian supplies reaching global markets - though at higher cost.

Turkey, Ukraine, Russia and the United Nations have been holding talks on ways to extend a deal brokered in July allowing the safe export of Ukrainian grain via the Black Sea, which is expiring on May 18.

Moscow has threatened to quit the deal over obstacles to its grain and fertilizer exports. The Kremlin said on Tuesday that questions still remained about Russia's part in the agreement, and that it would have to make a decision on whether to renew it.

Of about 20 senior Ukrainian and international traders and analysts polled by Reuters at the GrainCom conference in Geneva, a vast majority said they expected a renewal of the deal, though possibly with some delay.

However, "it doesn't matter whether it is renewed", Dan Basse, president of Chicago-based consultancy AgResource said on the sidelines of the gathering.

"With a lower crop this year, it can all go out west through eastern Europe. The problem is that it will cost 15% to 20% more," he added.

Nearly all the delegates polled at the conference said a much lower harvest expected this year had alleviated the pressure to export through Black Sea ports, and that alternative routes including rail, truck and exports via the Danube river would be able compensate.

"Do we need the corridor? I would say yes... But if we aren't going to have it, are we going to find a solution to export everything via the EU export corridor? I would say yes as well," Stefan Florescu, global head of wheat trading at CHS, the largest U.S agricultural cooperative, told the conference.

However, Nikolay Gorbachov, head of the Ukrainian Grain Association, warned that without the corridor export logistic prices would surge and cut farmers' margins so much that they would stop producing wheat and corn in big volumes.

Under the pact to create a safe shipping channel, Ukraine has been able to export some 30.25 million tonnes of agricultural products, of which 50% was corn and 28% wheat. Other commodities shipped include rapeseed, sunflower oil, sunflower meal and barley.

(Reporting by Sybille de La Hamaide; Editing by Jan Harvey)